Why was German Sloped Armor so late?

[@MilitaryHistoryVisualized]

Get our books here: militaryhistorygroup.com

[@darthcalanil5333]

the link takes to a Cloudflare error screen

[@joe6167]

It might be worth your time to look through Battleship New Jersey's channel, as they have made a number of videos on the implementation of welding into the construction of the ship, and the transition from riveting to welding. As welding was still an experimental process at that time they might have gone overboard with it, and all throughout the ship you can see how all the welds between the armour plates use a unique "scalloped" design, I guess to get as much surface area as possible, as opposed to a welding in a straight line. Perhaps the Germans were trying increase the surface area of the welds with the interlocking plates?

[@SlinkyTWF]

Is it possible that the interlocking of the plates could have been done as an aid to properly fitting and aligning the armor to make the assembly and welding easier and more consistent? I don't what the difference would have been in the factories regarding how the workers fitted the plates in position prior to welding.

[@TheRezro]

Short answer. It was unnecessary. Germans achieve this effect through tactic and proper angling against the target. While having profit of larger internal space. T-34 is heavily overrated and its angled armour was more due to poor quality of Soviet tank crews. Germans start using this effect more with they late tanks (if you ignore that King Tiger have horrible shot trap), where need of space was not so crucial anymore.

[@pierQRzt180]

uh the library grew a lot, before there were good works but not of my interest, now it is different!

[@bami2]

Germany forgot to buy the WW2 season pass and the sloped armor DLC was only available to non-premium players in '44

[@piellamp]

Gotta hate pay to win wars

[@RT-mm8rq]

Sloped armor or not a small fast and stealthly premium ( pay to win) light tank or TD comes on the battlefield that some how bounces hits from large calibers guns, is armed with a rapid fire small caliber cannon OR a large rocket that always seems to kill your crew, track you or set your tank on fire.

[@UnfollowYourDreams]

Understandable, these "service-based" monetarization models suck.

[@ФедяКрюков-в6ь]

They paid for armored cars DLC though

[@ФедяКрюков-в6ь]

​​@@UnfollowYourDreams"War is a pay-to-win game" (c) Giovanni Trivulzio, famous wargame designer of late Middle Ages

[@brennus57]

Thank you for this perspective. I've been puzzled that so many people fixate on the idea that the concept of sloped armor began with the T-34. You can see sloped armor on the ironclads CSN Virginia, Arkansas and Albemarle. Also thousands of examples in medieval tournament armor. This principle had been understood and applied for centuries.

[@karlheinzvonkroemann2217]

Can't argue with that one!

[@ФедяКрюков-в6ь]

The concept of a fort made of wagons is known at least since the first Indo-European nomads begun spreading throughout the Eurasia, but people fixate on the idea of wagenburg being invented by the czech hussites. Why? Because they were the first ones to make it into a system and employ such tactics with significant results against an opponent deemed to be superior in all aspects previously. The same goes to T-34. Germans didn't have all the bright ideas in the world, whatever the wehraboos are imagening to themselves while jerking off on panzers

[@pex_the_unalivedrunk6785]

Leonardo DaVinci tank concept also had sloped armor

[@ФедяКрюков-в6ь]

@@pex_the_unalivedrunk6785 gErMaN tAnKs hAvE sLopEd aRmoR aT tHe nOsE tOo!!1

[@dwarow2508]

Only that no other tank made sloped armor so effective and efficient as the T34 prior to that point. That is why it is celebrated so much. And evidently the principle had not been understood and applied for centuries when the T34 applying it basically seemed like a miracle to the Germans

[@oskar6661]

When people think Germany didn't "understand" sloped armour...I always wonder, 'Where do you think their engineers got their degrees?'. Sloped surfaces are basic physics/geometry/material sciences '101' level stuff.

[@SkunkdMonk]

Somehow German's completely missed the medieval armor period apparently lol

[@nightshade4186]

Yes it's Pythagoras law

Also, after WW1 Germany had many restriction on what they can and cannot do militarily. Soviet Russia helped educate German military in their war academies. And USSR and Germany where allies it the beggining of the war from 1939 to 1941. So Germans knew very vell what Russians where doing.

[@KuK137]

And yet somehow these geniuses never applied it anywhere in tank design producing complete trash design one after another until Russians made them laughing stock with T-34. Go figure...

[@KuK137]

@ Bullshit, if they were allies, nazis wouldn't send arms and men to countries attacking the soviets and soviets would help them with fighting somewhere. Pull the other one, yes I know russophobic revisionists produce endless nonsense today but there was no alliance, mild neutrality at best. And funnily enough soviet designs went completely ignored and laughed by nazis (because these dumb slavs can't produce anything better than us, right?) until they saw T-34 in action and collectively browned their pants...

[@silmarian]

“I was [certain] at one point and then I started to ask too many questions.” I think we’ve all been there. Sometimes the more information one has the less clear the answer becomes. I appreciate you being upfront about that.

[@timob3490]

Also welding had just been adopted for major industrial production. So welding processes were there but structural design had not really been adapted to the process. The interlocking plates are a really good example. They only chose to do so because the structural integrity would be better this way because they did not manufacture full weld penetration on the armour plates. This was a compromise on integrity and welding. The plates support themselves somewhat better by interlocking. But it makes welding even harder. You can tell by the poor weld surface and layers on these joints.

[@UnfollowYourDreams]

True. Interlocking increases the length and complexity of the weldseem, which was arguably the weakest part of armor back then.

[@carstenlichy-bittendorf3902]

Right, but the interlock keeps the plates better in position. This especially when welding plates in complex angles by less professional staff. So the interlock might simply have been a need for manufacturing. Just a thought - not a fact

[@Tuning3434]

@timob3490 True, but most of the welding was used in structural steel, not armour steel. I don't think this is the reason why it is used in armoured components, but in sheetmetal products those battlements are used (usually cause it is a 'free' functionality in a laser cutting process) to both position the individual plates, reduce the amount of weld (not the case in the armour) and to limit deformation due shrinkage of the welded area, actually, the weld shrinkage (in a proper quality weld that doesn't crack!) pulls plates in a stronger connection. I wonder if it was an attempt to limit welding jigs, by having the plates interlock closer together themselves? It feels a bit ungerman lack of Handwerkskunst, but it doesn't really show up til Germany really wants to ramp up production.

[@MarcosElMalo2]

Some of the welds look terrible with inadequate penetration. It looks not so much like welds but like they were stitching the plates together with small diameter filler. The weld on the M-10 looks sloppy but adequate. We can’t tell from a video of painted surfaces, but I imagine that the plates had been bonded into a single plate. I find it hard to believe that the Germans didn’t understand the welding process, so I wonder in the “joinery” was to compensate for a shortage of skilled workers on certain production lines. It would have been funny if the used dovetail joints. 😅 Supposedly stronger than finger joints.

[@gore0ru]

@@carstenlichy-bittendorf3902 - A novice welder will not weld such complex joints well.

[@pugnate666]

From an engineering view I want to mention 3 different effects of interlocking plates: 1. Your welding surface is bigger. Welds are a weak point, therefore you want to spread the load over a larger surface. 2. Shear forces between two plates are put onto the much stronger "teeth". (E.g. side view of a shell hitting the front of a panther. The frontal plate is forced inward and up by the impact. The interlocking on the sides of the plate works directly against these forces. 3. Welds handle load in different directions differently well. So interlocks change the direction at which forces act on the weld. (E.g. Frontal view of a shell hitting a panthers' upper plate: Again the plate is forced up and into the tank. A flat weld between upper and lower plate will just get pulled apart and open like a zipper. At interlocks, the weld experiences shear forces, which it can handle better and prevent the whole weld opening up as one.) Thanks for the video about this interesting topic!

[@pRahvi0]

Considering welding was quite a new technology and yet to mature, the welds of the time were or at least could often be weaker than after the war. I'd imagine once the welding techniques developed and welds became more reliable and better understood, the need for complicated joints was no longer there (thus interlocking disappeared from use), but it might well have been at the time they were used.

[@mordentus]

Large metal plates warp during welding. To prevent this, one needs to either build massive supporting framework or interlock the plates

[@Punisher9419]

All the German tanks still has slopped armour, it just wasn't slopped everywhere because of space problems. Even the front plate of the Tiger was slopped backwards a little 10 degrees I think.

[@_ArsNova]

Yes, exactly this. The Panzer III, IV, Tiger, all had sloped armor, just at very shallow angles. Sloping armor is always tradeoff between extra effective thickness, and decreasing interior volume and crew ergonomics. Soviet tanks are infamous for their atrocious crew ergonomics and coffin-like interiors for a reason.

[@TallDude73]

@@_ArsNova Agreed, I thought sloped vs. shallow-sloped armor was just a design and engineering choice. Sloped armor means more metal (the hypothenuse of the triangle) which weighs more (unless made thinner, in which case you lose the benefits somewhat) and covers a larger volume inside the tank. Not all of that volume is useful, and will be used mainly for the driver's and bow gunner's legs.

[@mrdojob]

The problem with sloped armour is that it doesn't actually help as much as people think. Sure you can tilt an armored plate 45 degrees, but in doing so you have to make the plate itself bigger to cover the same space as an unsloped plate. Sloping also creates a lot of space inefficiencies. You can cram more into an After 8 mint box than a Toblerone box.

[@aleksazunjic9672]

@@TallDude73 Slopped armor allows ricochets and this is its major advantage over straight armor of similar thickness. Disadvantage is that you have less space inside, i.e. you have cramped tanks (well known fault of Soviet tank design) .

[@_ArsNova]

@@mrdojob People also forget that sloped armor is only useful as long as it's sloped. It is rendered worthless if you happen to be caught in a position where that angle is nullified, such as while the tank itself is on an angled slope, or is being fired on from higher ground.

[@grizwoldphantasia5005]

Keep on asking questions, they are interesting. Answers are better, but you can't have answers without questions first.

[@danielstickney2400]

This type of keyed joint is commonly referred to as a "box joint" in English. You may wish to contact the Australian Armor Museum for their opinions about keyed armor joints, their restoration shop has actually welded blown-up German armored vehicles back together. They observed minimal and inconsistent use of armor grade stainless steel welding rods in the late production Stug 3 they are currently restoring, no doubt due to late war shortages,.

[@MarcosElMalo2]

I am very curious about the weld penetration the Germans were achieving (or failing to achieve). And I further wonder if this was caused by material shortages (as you suggest), skilled worker shortages, or welding technology lagging plate thickness. If box joints were supposed to improve structural integrity, why not go further and use dovetails? 😂

[@ianslaby5703]

@@MarcosElMalo2 the box joint is already inefficient compared to a straight line weld. Think about the fact that this would further increase the length of the weld and make the fitting of the armor plate even more difficult than a box joint no doubt does. Man hours are expensive, this might have been a compromise solution.

[@kilianortmann9979]

Sloped armor is not a magic bullet (pun intended), a sloped plate will have more effective thickness, but it needs to be longer to cover the same frontal height. Those two effects will exactly offset, the main advantage of sloped armor comes from normalization effects, simpler production of thinner plates and better surface to volume ratio, when designed correctly. For modern APDSFS projectiles with a large degree of positive normalization, sloped homogeneous armor can be worse than a flat plate. Especially in a WW2 context there are definite advantages, but also tradeoffs.

[@quantum340]

Yes! Thank you! It always drove me nuts to hear that 'sloped armor increases effective thickness for the armor without increasing its actual thickness, so you save weight' when simple geometry shows the increase in length of the armor plate would cancel out any supposed weight loss.

[@thrall1342]

This, 100% I have been writing this for some time as well ... angling a plate doesn't save weight by itself. The weight saving come from decreased surface area you need to cover and less internal volume.

[@quantum340]

But can you explain these 'normalization effects'? What are these and how does it affect flat and sloped armor?

[@kilianortmann9979]

@@quantum340 If a projectile hit's a plate of armor at an angle, it gets deflected. For a normal upwards sloped plate, most basic bullets get deflected upwards, like a ball. They don't penetrate the line of sight thickness, they need to penetrate a longer way, leading to increased effectiveness of sloped armor, this is de-normalization. Specialized armor piercing caps will "bite" into the armor, deform and turn the rest of the projectile downwards.The projectile will now only need to penetrate a shorter distance, closer to the plates actual thickness. This is normalization (the projectile turns towards the normal [perpendicular] to the plate) and this makes sloped armor less effective. Modern armor piercing projectiles and especially APFSDS have positive normalization. Example of WW2 era de-normalization kzbin.info/www/bejne/m6vJYZWOYpqFZqM Example of APFSDS normalization kzbin.info/www/bejne/ZqWQh5xqqtOHgrM

[@piotrmalewski8178]

That's why T-34 was supposed to made of high hardness steel to make advantage of the armour angle to deflect shells, but it had side effect of internal cracks hurthing the crew on hit, and Soviets had trouble maintaining any production standard in the first place.

[@russwoodward8251]

In manufacturing, interlocking plate would make the jig necessary for hull assembly, simpler, as the locking tabs would insure alignment in two directions. Since these plates were heavy heavy heavy, simplifying the jig would be a goal of any factory engineer for sure. The Soviets may have tried it for the same reason. To simplify alignment for assembly. Thanks Bernhard!

[@_ArsNova]

My eyes almost roll a full 360 degrees any time I see someone talk about sloped armor as if it began with the T-34. The Germans had been sloping tank armor since WWI with the A7V. The literal first "tank" concept in Leonardo Da Vinci's drawings from 1487 had sloped armor!

[@Blox117]

so what you are saying is that leonardo da vinci was russian?

[@josephahner3031]

Da Vinci's tank didn't have sloped armor for the purpose of increasing protection, but because of how the armor would be constructed, bound at the top.

[@_ArsNova]

@@josephahner3031 Perhaps, but even back then people understood that cannonballs and other projectiles were more easily deflected by angled surfaces.

[@oskar6661]

Fun fact, Leonardo Da Vinci's tank could withstand a 76.2mm ZiS-3 AT gun at distances of between 600+ meters.

[@gore0ru]

@@Blox117 - Or German LOL

[@pavelslama5543]

Vehicle designers of that time had only a vague knowledge of the effects of shell denormalization, and how to instigate or mitigate it. Their thinking of the efficiency of armor boiled down to mostly sine of the angle from horizontal. What it means is that they said "80mm at 40 degrees from horizontal? That´s just about 125mm. That´s not good enough." Meanwhile the reality is that almost no shell was stable enough in order to "bite" into that angle without major deviation upwards. Modern simulations suggest that Panther II with its 100mm thick front armor would be almost impenetrable even to the mighty Soviet 122mm gun.

[@nattygsbord]

125mm is good enough. It is very good. Tiger I was considered almost impossible to knock out and it "only" had 100mm front armor. So personally would I consider 70mm armor with say a 50 degrees slope (or more) to be good enough for a medium tank. Having thicker armor than that would only be wasteful in my opinion and bring extra weigth, slow down the tank, make the tank too heavy to the front, having too much armor at the front so weight have to be saved by cutting down side armor and making the tank weaker and vulnerable to hits from the sides, rear and top. So I think your suggestion is a bad idea. And then it also depends on the type of tank. Hetzer would I consider to be extremely well protected. Its small and easy to hide. And the enemy cannot shot at you if he does not know that you are there. And when he discovers you, then he will have a diffucult time hitting a small target like the Hetzer. And Hetzer in a hull down position its even harder to see and to hit. And if you manage to hit it, then will you probably only hit it where the armor is the strongest - the frontal top of the hull. And there will the thick armor with a sharp sloping give pretty good protection, even against pretty large caliber guns at longer ranges. So its a pretty cost-effective use of armor the Germans had with this little vehicle.

[@sergeyboychuck8872]

reality harsh, IS-2/3 had zero problems with their 122 mm against Tiger's.

[@sergeyboychuck8872]

@@nattygsbord you just described T-34/85. my congratulations!😁

[@nattygsbord]

@@sergeyboychuck8872 T-34 and M4 Sherman did have sloped armor and somewhat okayish thickness. So I think they were better designs than the German tanks that either had crappy armor or was too frontally heavy. I guess low quality steel in the russian tanks made their frontal armor not so fully effective as their american counterpart. And bad tank crews and poor ergonomics and other shortcomings could probably explain much of the high soviet tank losses. But the general idea was sound. It had frontal armor of the right thickness. And it had a gun of almost the same calibre as a Tiger I and inside a medium tank.

[@nattygsbord]

@@sergeyboychuck8872 But you are comparing apples with oranges I think. Tiger I was an old design. It was very good at its job facing tanks made before its introduction in august 1942. But it was never really meant to be invincible against tanks made after that. And the Soviets also deliberatly armed their tanks with the only guns they had that had been proven effective against the Tiger - such as the 85mm Anti-aircraft gun they put in the turret of T-34. And the 122mm gun they gave IS2. And the 152mm gun on SU-152 and ISU-152. No tank could survive a hit from those guns. Just like no tank today can survive a direct hit from a 155mm or 152mm artillery piece. But it would be stupid to say that armor protection does work because it cannot survive direct hits from high calibre guns.

[@RJ-vb7gh]

I'm not sure this makes any sense to me, but as a young man I knew a "tank escort" for the German Army (the guy who walks along side tanks into combat), He served from the beginning of the war to the fall of Paris. Mainly he escorted tiger tanks on the Russian front until losing a kidney and being assigned to guard a tiger during the fall of Paris, where the tank overheated and he got captured still escorting it. So here's the weird part... he told me that the way the Tiger was designed to deflect shells straight upwards. And he claims that's exactly what they did in his actual experience on the Russian Front. He mentioned that Tiger crews preferred to assault or defend from the high ground. and he also added that most Tiger gunners could hit a moving jeep at 1000 meters. While I have to agree that it's unlikely that incoming shells would ever come at a tank straight on I don't quite understand why incoming shells would always ricochet straight upwards. Lastly, at least through quite of a the war, German tankers weren't too concerned with Russian tanks or most other Russian munitions that they were encountering. For the most part they felt that they could outrange the Russians and survive incoming hits. I wish I remembered more of that conversation, but that was nearly 50 years ago.... Perhaps for WW 2 buffs in general, I'll add a couple of fun trivia that he told me: On the offensive towards Moscow the tank guards were usually tasked with capturing meals. For the most part this involved capturing Russian soldiers and confiscating their food. They might capture up to 60 Russians in a morning forage and he said, the Russians didn't necessarily have bullets, but they always had good food. He went on to tell me that things went terribly wrong when the quality of the Russian Food declined and the Russians suddenly became flush with resources and ammo. In his mind the Russians had somehow built a great factory that produced everything they needed and cost Germany the war. He didn't speak Russian or English, but he memorized the name of the factory and he wrote it on the barn wall in pencil.... it read...."Made in USA" which he pronounced as one word in German and I didn't get it until he wrote it. I of course translated the word for him and we both walked away from the conversation having learned something. It's been 50 years and I thought I might share this little story before it's lost to history.

[@keithbosch37]

"Madeinusa", thanks for sharing this.

[@stage6fan475]

Thanks a lot for sharing this.

[@2Pzp]

Great history! 50 years ago? How did you meet him?

[@RJ-vb7gh]

@@2Pzp I spent a summer living on his farm in Germany as a kid. He was my mom's first husband's step brother. He didn't have a son, so he spent time with me teaching me about farming and every once in the while sharing his WW 2 experiences with me. He was a quiet and contemplative man who liked to work with his hands and with animals. He made it all the way to Moscow and ended his military career in Paris. Along the way he earned an Iron Cross with decorations and I suppose is now one of the many that were heroes for a time and have since been lost to history.

[@RJ-vb7gh]

@ZaHandle Yup. It's easy for a 21st century English speaker to understand, but can you even imagine how confusing and terrifying it was to a German soldier who grew up a farm boy and neither spoke English nor Russian and only had Nazi propaganda and one clue "Made in USA" to help him understand why his life and the war was going to shite.

[@billyponsonby]

Very interesting. Not all research arrives at a neat, interlocking conclusion.

[@mikecanaday1631]

American examination of German armor, specifically a PzKpfw III gave a low opinion of the choice of welding rod, but a high opinion of the armor plate.

[@MrEolicus]

Thank you for being honest. When one speaks plainly about what one knows and one knows not, a new plethora of information is conveyed. It also messes with your intellects in a good way... certainty is a transient state. That fact is often forgotten. Great channel! Cheers.

[@vladimpaler3498]

Another thing to consider with the interlocking plates is that you get more weld length and it is split across both plates. A simple butt joint leaves the plates subject to flexing along the weld length, while interlocking provides more rigidity. Might help keep welds from failing when a shell hits and flexes it.

[@karoltakisobie6638]

From welder's perspective: straight welds are faster and worker doesn't need a lot of experience to make a good weld. Interlocking plates present a challenge because on one hand welder can do his job in such a way that will prevent material/ weld stress ( comparing to straight weld). On other hand interlocking joints will take much more time, effort and weld quality will be often questionable. Look at pictures of knocked out tanks. Very often it's the welds that let go,not armored plates. Want to make welder's life hard? Design welds like those of Churchill tank ( as observed on example in Borden Base Ontario, Canada). What a nightmare.

[@MarcosElMalo2]

And if it’s the welds blowing out, that means their welders aren’t getting full penetration.

[@causewaykayak]

This is a channel with great integrity.

[@damagingthebrand7387]

As long as you do not hit his seams.

[@unknown0soldier]

This video left me with more questions than answers. And I think that's cool, so thank you!

[@MilitaryHistoryVisualized]

Thanks! Same here :)

[@shiftymcgee4183]

Love the progression of this video as more information comes to light👍

[@ThePerfectRed]

One important aspect of straight box armour is that you can use the inside surfaces much more efficiently to mount equipment, and it generally gives more room to the inside.

[@ianslaby5703]

Interlocking armor plates is an interesting but separate topic from sloped armor, because clearly you can do one without doing the other. About the positives and negatives of interlocking armor plates: first off, as you mentioned, thick tank armor is hard to cut (especially with the precision necessary to create interlocking), cutting it into this shape will take more time because the length of material you need to cut is longer than a straight line, the same problem appears with welding. Obviously these are two very expensive, material and time consuming processes, I think that they probably had a reason for them. I think the main benefit to interlocking the plates like this is impact resistance. Welds are generally more brittle than the slabs of armor that they join, when they get hit, they sometimes crack, even more rarely, the entire weld cracks and the structural integrity of the hull is compromised without a full penetration of the armor. I think that this is what they wanted to deal with. If a weld like the one on the Tiger II is impacted, part of the weld might crack, but the crack will only travel down the weld in a straight line, once the crack has to make a 90 degree turn to follow the weld, a lot of the energy will dissipate. This makes the weld tougher even though Germany did not have the best welding technology as you mentioned. This is of course all speculation on my part based on my limited knowledge of armor manufacture, welding, material science and other topics. If I got something wrong please tell me!

[@lisandromc78]

Hah! Yesterday I was looking at the pictures I took at the Panzermuseum and wondering why the interlocking plates. Just a few hours later you come up with this video... 😲 Great work, Bernhard!

[@AJ-qn6gd]

SIRI is always listening 🤔🇬🇧

[@akk-nd3vj]

i remember reading from some book that boxy pz was cos sloping reduce space inside the tank

[@centsparta4280]

Hi, The German tanks adopted interlocking armor because the steel quality was much lower. The German steel had a much higher carbon content which made the welds subject to cracking along the weld seams. the Interlocking was a way to reduce the weld stress on the joints.

[@MilitaryHistoryVisualized]

Source?

[@Pihnes]

The interlocking welds/steel plates can also be found in warships like the Iowa class New Jersey. Basically, by increasing the surface you'll get a stronger weld.

[@MarcosElMalo2]

That’s not how welding works. It’s very different than wood joinery. In welding, you are bonding two pieces into one solid piece. The weld needs to penetrate the thickness of the metal and you need the proper amperage going through the electrode/filler rod. You are fusing metal together. In a wood joint, increasing the surface gives you more glue surface. That’s what you’re thinking of. The interlocking plates you saw more likely were to aid in more rapid construction-it would allow more rapid positioning of the plates before they were welded.

[@kirotheavenger60]

​@@MarcosElMalo2a longer weld means the two metals are joined together over a larger surface, increasing strength The mechanism might be a little different to glue, but in this regard it's no different

[@jonassackarndt1174]

I really liked the video and highly appreciate your honesty on the level of understanding you have. I was a little bit surprised to see the first part of the video and i think it is rather interesting to think about the connecting mechanisms of armor plates. I personally think it were the drivers vision and the crews and engineers being used to the layout. It is not completely neglecting sloping, it just tries to minimize the size of the visory hatch. Also it might have been an influence that the tank would effectively become a little shorter. As soon as more communication was inteoduced and also no more direct vision was required it was possible to drive without that weakspot. I really wonder if the big hatches of sloped vehicles or the vertically closing hatches of german tanks were seen as a weakspot by the soldiers of that time or as a necessary thing because driving blindly was seen as more dangerous than having a thin weakspot.

[@MannoMax]

As somebody that has to assemble large heavy parts for my day job I have another idea as to why the mortises were there: Ease of assembly. Moving large, heavy, armor plates into exact position for welding is way easier if you had those notches as a guide. This would also explain why germans did this on the "heavies", but not on the 3s and 4s, and why none of the allies really used it. If you're doing well prepared mass production of a tank, you can build welding fixtures that quickly position the plates, regardless of notches, but if youre building them at a lower volume, its easier to cut the plates with notches, instead of building an entire fixture before you can start production

[@andrewflindall9048]

Interlocking (as my original post appears to have disappeared) was an economic measure. Major joints were not plain butt joints. The machining required to rebate joints was expensive in terms of time and tools. Interlocked joints could be gas cut relatively quickly and cheaply. Jigs were still needed for assembly as tolerances were much looser, becoming shocking in some cases later on (joints needing to be packed/shimmed before welding). Chapter and verse: Final Report - Welding Design of German Tank Hulls and Turrets 1948

Der Disclaimer zu Beginn…mit nettem Augenzwinkern zu unseren Behörden mit den „richtigen Prioritäten“ 👍👍👍

[@adoramus]

Thank you. Great channel and great video.

[@paulkurilecz4209]

One thought about the use of interlocking plates in welded construction. Even before the development of fracture mechanics, it was well known that welds were more brittle than the material that was joined by the weld. Perhaps this interlocking joint design was meant to limit the extent of a weld failure due to impact from a shell.

[@SwordGuardian]

It takes a smart person to assume their right, but to learn more and admit they are unsure. I can always trust this channel to present information in a thought-out and honest way, without letting bias get in the way. And to be fair, the different possibilities presented in this video don't necessarily exclude each other, and more likely, both the structural integrity of welds and the need changes in needs of vision ports contributed to the use of slopped armor.

[@Anymouse6980]

I am a new viewer of your channel. I have seen your with the Chieftain. Great presentation with facts and interpretations, and indicating when your statement is an opinion. Keep the good work. I appreciate your views based on access to German source material. Thanks

[@jan-eric-schacht]

Writing this before having seen the video. Look at the turret of the Panzer I and you will see sloped armor. There was sloped armor right from the beginning. Maybe not as much as later, but others didn't have much sloped armor as well. Look e.g. at the british tanks including all the Vickers copies... Also with the early recon cars like SdKfz 222 you find sloped armor.

[@joechudleigh94]

My mate is an engineer, he builds and designs trailers. He always uses interlocking where he can. He told me that it provides good strength and shock absorption and stress is distributed equally

[@MarcosElMalo2]

Ask him about welds.

[@joechudleigh94]

@@MarcosElMalo2 Yeah sorry thats what I meant interlocking puts less stress on the welds and distributes pressure evenly. funny enough where the welds have broken (his designing a new trailer for farming) is were the parts cant interlock.

[@justinbrown691]

I think you have it right. Boxy was easy and it worked given their welding abilities. Evidently, this equation changed for them fire power increased. Really interesting video and topic in general.

[@jckluckhohn]

Learned something today thank you

That’s the problem with history, it’s so often raised more questions than it answers. Great video as always 👍🏻

[@robm4834]

Interlocking plates would be able to be assembled and left for welding. Meanwhile the crane can move to next part built tank n place next interlocking armor plate, again n again. Freeing up crane and ensuring plates are in correctly and workers safety. Also by 1943 skilled workers were harder to find , thus interlocking plates may balance structural integrity as weld quality had been reduced.

[@gerhardris]

Thanks for a great informative video adressing problems I also asked myself why noone answered them. I love the way you simply state what you know don't yet know and find out later. The hallmark of a trustworthy source. As a former Leopard 1 driver I too noticed the interlocking teeth way of armour wasn't continued. Albeit the phylosophy changed I guess after having lost the war to many Shermans etc. Indeed also what you mention welding techiques and steel quality come into play. As do periscopes we called episcopes due to only mirrors and no optic lenses. I also thought it might have been the room and weight considerations. Sloped armour costs a lot of space inside. The smaller the tank and relative old engines are larger and more awkward old tanks especially British ones had lumps of steel.plate to get it all to fit. So I guess it was a mix of many factors that come into play. Cost, availebility etc. So, the jury is still out on a new line for many video's of choices. And of course talented and less talented engineers or traditions in industry. Anyway, keep up the good work.❤ 16:32 What

[@ERIK-457]

I imagine that interlocking welded plate armor both spreads the stress on a longer weld line, and also the geometry itself also helps to lock the plates in place more strongly also aiding to keep the whole thing together and not relying purely on the welds, i think this was specially important for the germans at that time since their steel lacked components to increade flexibility and reduce overhardness, so with harder plates interlocking is also more effective, but also needed so the plates dont crack at the welding lines or so that the welding lines are stronger

[@nathanpowell195]

Videos that show the process and challenges of reaching rigorous conclusions are better than videos that present everything as settled and tidy

I recently just cought a massiv error in one of my videos before blasting it out to the world :) The devil really is in the details and unfortunatly most of the time differences arent as clear cut as we simple man would like them to be :) Nice Video

[@CAP198462]

The point about the driver’s direct vision hatch was interesting, I hadn’t noticed that before. It’s also amusing how similar the interlocking plates look to Lego bricks.

[@anotherneo231]

thanks for this honest information

[@marcdunord]

making dovetails for surfaces that meet at non-right angles requires much more complicated machining than for surfaces that meet at right angles (like in conan's german game show channel)

[@exharkhun5605]

The interlocking armor has to do with the surface area of the weld. It became necessary as the armor plates became thicker. Depending on the welding technology, and this was hugely different between countries back then, you weld only at the surface of the joint between plates. The interlocking creates more connecting area to weld, and thus stronger weld's. You don't need the interlocking (as much) if there's structural framework underneath or if only one of the plates extremely thick. It's main purpose can also be during construction, to hold something in place so a good weld can be made. That's why you may see it pop up situationally. After the war the hugely thick armor plates disappeared, or were created in different ways. Welding techniques also changed and improved.

[@vladimirpecherskiy1910]

Exactly.

[@ven7165]

What I had assumed was Germany's tanks were designed for a war that used weaker guns and designed at a time when tanks were novel and so what could/should or could/should not be done with a tank was in question, as well as the fact that a box-like design was easier to design and manufacture.

[@patrickvolk7031]

One of the obvious (maybe oblivious) things to me about sloped armor is it increases the surface area of the armor you need. For heavy designs, and maybe due to efficiencies, the Germans opted for thicker as opposed to bigger. It may also be that when the shell was AP-C, the hardness was expected to defeat the shell. When it got to KEPs or shaped-charge rounds, it concentrated the force enough to defeat hardened armor, and deflection of the penetration path was more a thing. As far as why sloped on early vehicles, bullets on thin armor would dent it, and cause bullet spall up the face. The US was casting hull parts by the end of the war, getting rid of the welds.

[@michaelguerin56]

Aah … the danger of asking questions, just as you start to think that you have the answer😁! Cheers from NZ🇳🇿.

[@utzius8003]

An interesting angle to view this through would be as to the reason the Soviets did not employ sloped armor on the KV-1 tank.

[@Juel92]

My guess is that the vision ports and crew comfort/effectivity was prioritized to the point where the engineers thought the slopes would be too much of a negative.

[@brealistic3542]

One of the first uses of sloped armor is in Leonardo da Vinci's proposed wooden tank. There is also a very interesting 1730+ period America sloped sided gun boat which is still at the bottom of Lake George NY. Site of the Battle of Fort William Henry, in the French and Indian war. Because of the lake's water conditions its still in almost like new shape.

[@Riceball01]

The thing about German tanks and sloped armor is that German tanks from the PzKpfw III up to the Tiger did have sloped armor, at least on the front of the hull. It's just that it's not set back at a very steep angle, but it is sloped and not sitting at 90 degree vertical. If you look tonkas like the Tiger from the side or a at slight angle, you'll see that the front plate where the bow MG and driver's view port are mounted are sloping back towards the top. And nose of a Tiger is completely sloped.

[@charlesfaure1189]

The T-34 was a horrible tank to have to fight in. The sloped armor on a relatively small vehicle was a major reason for that. The Germans went to sloped armor as their tanks got bigger (and therefore roomier for crew and ammo, etc.) Better armor protection isn't worth it if your crews can't fight the vehicle well.

[@typxxilps]

that is a really great one considering all the reasearch required !

[@nekomakhea9440]

You can see these jigsaw-like weld joints on warships too, USS New Jersey's youtube channel shows some of them used in battleship construction. They mention that welding is a new technology at the time, and they use a mixture of rivets and zig-zag welds because welding isn't a tried and trusted technology yet.

[@anthony3968]

The interlocking of the armor allowed for welding of only one side without loss of strength. The Sherman was welded on the inside and out side of the plates for strength. Dove tailing the plates eliminated the need for the extra Welding.

[@xt6wagon]

FT17 loved sloped armor even if it was barely armored. Another reason for the step is no one had a hull MG that worked on sloped armor early on.

[@xXxTripleHxXx]

The stepped hull is also beneficial for maintenance as it allows for easy access to the transmission. Back in the day the drivetrain was not combined into a dense package that can be lifted out as a single piece instead the components were spaced out more to ease maintenance. The reason why rear engine front transmission was done Is so that both could be placed in a smaller space than what would have been needed if you wanted to put them into a single compartment without compromising maintenance.

[@georgepatton93]

My guess, If you have good steel quality, you can get some good armor, slope armor is just A factor, not THE factor, not to mention slope armor can limit the space inside your tank if not designed properly

[@xxw379k]

Interesting to hear about the backstory to the Volvo 240 series.

[@DirtyHairy1]

It takes ballz to say "I don't know" in an educational video.

[@SM-xc4rl]

Betreffend der verzahnten Panzerplatten. Ich war mit meinem Großvater mal im Museum und fragte ihn nach diesen "Zähnen", sah für mich als Kind so aus. Er erklärte mir, diese Verzahnung erleichterte die Herstellung der Wanne, denn die sehr schweren Panzerplatten mussten so nicht per Kran gehalten werden, während sie verschweißt wurden. Nachdem der Kran die Platten so abgelegt hatten, dass sie ineinander gegriffen haben, konnte der Kran anderen Tätigkeiten nachgehen. Es könnte natürlich weitere Gründe geben, aber die Erklärung erschien mir plausibel. Leider kann ich ihn heute nicht mehr fragen.

[@johnvlahidis_google]

your coment is better than 16+ minutes of this crappy video thank u!

[@krakken120]

the tiger is sloped, they just doctrine it different to be at an angle in engagement instead of spearheading head on

[@sebastianb5036]

Didn't the Tiger Handbook advise to angle the tank towards the enemy? By doing this you basically neutralize the disadvantage while still maintaining the benefits.

[@MilitaryHistoryVisualized]

That is horizontal angling, sloped armor is vertical.

[@JohnR22926]

I would really consider that halftrack to be "armored". That metal plating is designed to protect from small arms and shrapnel, and imo the sloping is incidental to the shape of the vehicle.

[@ianmarsden6276]

Very good video, very informative. Perhaps an additional reason is that sloping the armour reduces the internal space for crew ergonomics, ammunition storage, equipment etc. Therefore if you want a tank that has the same internal space as a flat plated tank then the overall size of a sloped armour tank must increase making it easier to hit and costing more per unit in materials and man hours to construct. The Soviets got around this issue in the early T34s by having small and uncomfortable tank crews.

[@PitFriend1]

One reason I’ve also heard why the Germans (and also the British) held off using sloped armor for their tanks for as long was the mounting for the hull machinegun. The ball mounts they used didn’t work well with a frontal slope which is why both German and British early war tanks had the flat front plate. The Germans still had problems with this even with the early Panthers, instead of a ball mount those tanks had a “letter box” slot for the gun to shoot from. They did figure it out as later Panthers and King Tigers had ball mounts. Even the Soviets had problems with this, if you look at the T-34 the hull machinegun has a large bulge out of the slope so the gun can be mounted flat. Only the Americans seem to have figured it out with the ball mounts with the one in the M4 Sherman with its sloped front armor. I have no idea if that is indeed the case but it does make some sense.

[@josephahner3031]

Sloping was first seen in late medieval castles soon after the development of cannons. It was first applied to tanks in practice WW1 but in theory even the Da Vinci tank had it. Though the Da Vinci tank was designed that way for structural reasons rather than for enhanced protection.

[@ChaosWolf3]

My initial response based just on my own visual interpretations and basic understanding would be that it was related to aspects of the interiors. So the driver vision ports do make sense. One thing that has to be considered is that, while the sloped armor all around the T-34 tanks were good for protection, these sloped also limit interior space considerably, which has a negative impact on ammo stowage, crew comfort, crew capacity (sloped T-34 turrets feature a 2 man crew instead of the usual 3), and other factors that can affect crew performance. I expect this to be one of the reasons that the Sherman had sloped frontal armor, but flat sides and that the side armor being the primary stowage of ammunition in the early war days was no coincidence. I don't think there's one reason alone why Germany used box like designs until later, I think there are multiple, very complex reasons. From production to interior space and function as well as crew comfort and even compatibility (tall people were harder to fit into tanks), the list of reasons a box like design might be better is quite extensive.

[@EllenbergW]

As quite a few here have said already, sloping your armor to a significant degree also reduced the available interior space by a significant degree. Keep in mind, that even in a high intensity conflict, the time a tank is actually fighting is a small fraction of the tank being in the field. I would assume that having a tank-crew that is fit and ready to go when that fighting time actually comes around, is much more important than having a bit more protection - this might be one reason, the German tankers could deal with the (on paper) superior French tanks in 1940 and Soviet tanks in '41. Note: I think it was the chieftain who said in his review of the Pz III, that this was probably the best tank of the early war, because, among a few other things, it's excellent ergonomics.

[@chengong388]

Sloping increases effective thickness, but you also need a longer plate to cover the same height, which probably doesn’t weigh that much less than just a straight but tricker plate.

[@maryambintghassani2341]

You are forgetting that German doctrine for PZ III, IV and VI was to take an angled approach to the enemy guns, moving forward by alternating between 10am and 2pm positions. This means the frontal plates ARE angled from the perspective of an opponent at the 12 position. The utility of additional angling in a second plane is questionable in such a position.

[@gore0ru]

Didn't the Germans know that guns could be rotated?

[@maryambintghassani2341]

@@gore0ru I'm not sure what you mean. The entire point is the tank gun is rotated but the frontal armour remains oblique to the enemy.

[@СлаваПшеничный-д3й]

​@@maryambintghassani2341, yes but what about side armour?

[@maryambintghassani2341]

@@СлаваПшеничный-д3й A weakness, obviously, but as it would also be oblique to the enemy, it would also be less vulnerable than it appears.

[@geronimo5537]

I believe the interlocking armor is a product of the intelligence war between the various countries and germany. Where the germans were convinced this extra step was needed for some reason. Thus slowing and complicating their production of armored vehicles slightly. It makes the most sense given the idea has completely faded away almost directly after the war.

[@harrysibben7583]

With interlocking plates there is more surface area to weld. Which makes it a lot stronger.

[@toddellis8346]

I think in this, there are three different points which are getting caught up in the same topic, being: 1. Sloped armor 2. Heavier armor. 3. Effective welding of sensitive armor plate. the interlocking joins are not exclusively related to sloping armor but are more a factor relating to effectively joining the ever increasing thickness of armor. In the case of the deflected shot being turned away (action/reaction) there is also an increase in stress that must be effectively distributed through the welds . These gargantuan thickness plates cannot possibly be fully welded so the strength must be achieved by other means. Keep in mind any welded structure achieves the required strength not through the welds themselves but through correct weld placement and correct fit up before welding. With all that said, in my own opinion all the sloped side armor was largely a waste of effort, a pointy nose and vertical sides seems to have stood the test of time.

[@varvarith3090]

The concern with welds breaking might be related with the way USSR army dealt with tanks: While germans primarily used high velocity cannons with armour piercing ammunition, soviets mainly used mortars and 152mm artillery. When i looked on soviet destroyed tanks report the line "152mm direct hit, front armor plate blown off" was recurring so often, it was the first thing i remembered when watching this video.

[@JRSimoes]

First off great video as always!! I have always supported you guys by purchasing all your books. I have every one in English. Unfortunately my german is extremely rough and out of practice. I see some books that only have german versions. Any chance you guys are working on translations into English for those? Keep up the great work!

[@MilitaryHistoryVisualized]

Thank you! Stug is being slowly being translated.

[@adlerarmory8382]

It's interesting the production economy increased due to improvements in metal cutting and welding technology. I thought just the fewer parts and seams of the monocoque style build was always the reason. (ArtieJohnson-Very interesting.)

[@RobertDerusha]

I'd like to see how the hulls were set up in their jigs for welding. I could see it being easier to quickly and cheaply construc hulls without having to build complex forms to hold the plates in place. You cut the plates to size, then interlock them with gauge blocks as spacers then weld it up removing spacers as you go. Note the interlocking shows up on newer designs when more tanks are needed quickly and Armour is thickening. Just a thought.

[@Modellbauer403]

Why do not understand so many people that if you put more armour due to sloping in the way of an projectile, you need proportional more armour for the higher armour effectiveness?

[@boelwerkr]

In my opinion the interlocking was a result of war production, not so much of general concern of stability. Welding can result in much harder or softer, and brittle connections. To get the right hardness and elasticity a lot of factors have to be right. The welding rods have to be dry, they have to be the right alloy the flux have to be the right composition. The base material has to prepped right and needs to have the right temperature. If you allow a wide error margin in the welding rod production and handling you have to compensate elsewhere. They used the interlocking for that. The production of rods was stable and comparable cheap with not much rejects. Transport and storage was easy. The prep work wasn't complicated. That was saving a lot of non recyclable material and time. The more work in cutting was less expensive in the view of the organizers. It would also allow less experienced personal to work on these projects because the quality of the welds didn't need to be very high.

[@orkako]

Inclined armor was already used in the Middle Ages. Back then, the armor of knights was specially inclined so that the blows of spears and swords would slide down the armor. Subsequently, this art was applied to the construction of castles, where increasingly sloped walls were built to cope with increasingly accurate artillery weapons. Ships, too, gained sloping armor, although this was originally due to the imposed tax on the deck area, so the sloping sides resulted from the reduction of the deck. It turned out, however, that the inclined side not only allows the ship to pay less tax, but also to deflect cannon shells. The inclined armor continued in the first ironclad ships. First during the Crimean War (at that time such armor was used on floating barges) , and then during the Civil War on monitors Inclined armor can already be found among the first tanks, but there were technological problems to fully incline the tank's armor. The first problem was the visors, as mentioned in the film. The thicker the armor was, the more difficult it was to cut a proper hole. In addition, when cutting the hole, there was a risk of damaging the plate, which was already only suitable for remelting. Another problem was the complexity of the design, this lengthened the production process, production time and production cost. The thicker the armor plate, the more all these costs increased. The very process of fitting and welding the inclined armor plate was complicated. During WWI, inclined armor was not a big problem, as long as it did not exceed 45' of inclination. This was due to the fact that armor plates were riveted to a special framework. An angle less than 45' prevented riveting. It was possible to get around this by creating a more complex shape from more armor plates, but this increased cost, vehicle weight, production time and did not make the armor more resistant to hits at all. Quite the opposite. The revolution came after the war with the use of bent plates, but this worked well with plates no thicker than 15 mm. Bending thicker armor required creating wider bend arcs and special techniques for hardening steel. Even so, bent steel exhibited weakened ballistic capabilities. Even welding was not an immediate solution. Welding in the 1930s was still a fairly new technique and was not perfect. There was the problem of welding sheet metal at unusual angles, large thicknesses, and armor plates that were too heavy. The Americans developed the relevant technology only with later models of the Sherman (although they had already experimented with it with the M3 Lee There was, however, the problem of cracking welds to vibrations and stresses at that time. The Russians did not have to develop welding technology, as they received the appropriate technology from the US, as did the British. The Italians and Japanese received their welding technology quite late from the Germans and did not have time to implement it in series vehicles. The alternative to welding was cast armor. It was cheap and quick to produce, but less hard and, on top of that, without the right technology, emitted numerous fragments inside when hit. That's still not the end of the story, however, as sloped armor complicated access to the gearbox, and placing the gearbox at the rear would create numerous technological problems (the T-34 had huge problems with the gearbox. The last gear had to be put in by hitting the rod with a hammer, while the gearbox itself had a very short lifespan, so there were T-34s carrying a spare gearbox on the engine compartment vault.

[@jpl7909]

I think the notched plates is mainly due to manufacturing and material constraints. With the notches, they can fit plates together like puzzle pieces on the assembly line before they move on to get welded. There's no need to brace the plates in position, or drill the plates and use precious bolts. I'm guessing all machining and fasteners were in short supply. Simplifying the design by not having to try and wrestle with sloping affecting internal working volume and construction complexity, especially when using already extremely thick armor for the time, was probably seen as a good trade since they were already struggling to meet demand for vehicles. Once they saw the escalation in enemy guns and munitions, sloped armor is a relatively easy way to up-armor to meet that threat. It does seem like when you can do blitzkrieg, having hyper-optimized armor is of minor importance. Later, as the army is bogged down and tanks must soak up more punishment that can't be avoided by rapidly defeating defenders, pulling out all the tricks and optimizations becomes crucial.

[@marcelcoetzee7152]

Probably because they figured it would be easier to add more armor onto the flat designs. It didn't work with the Tiger 1 but Panzer 3 and 4 had quite a few armour thickness upgrades during the war i think. I don't think any German or Soviet designs up armored a sloped hull design during the war. It would probably be similar to the issue that happens when adding ERA to tank that wasn't designed for it.

[@paulschafers5983]

I would agree with your comment that they felt it unnecessary until allied firepower improved, such as T34/85 and Sherman Firefly

[@Hive-Mind-BBX]

Sloped armour is basically on every WW2 Armoured vehicle, however, it was rarely implemented into design intelligently to act as sloped armour. In fact, many of the vehicles with a lot of armour sloping in early WW2 were pre-war designs like the Soviet T-60 for example, which is a pre-war light tank design, but the front and rear armour is sloped. Additionally, most nations with tanks at the time of WW2's start, had at the very least made something with mostly sloped frontal armour.

[@techforge-Nate]

Square armour like the Panzer 3/4/Tiger can still be angled by positioning the tank and shooting over one of the front track wheels. If you have pike nose, or sloped armour that is angled for frontal deflection, if you are caught from the 45 degree angle to the hull, these plates are more or less flat. Early German tank doctrine also had more emphasis on mobility than protection against tank guns, which meant the square designs were adequate for that doctrine, while also remaining feasible for production as Germany were coming from a very low technical and industrial base compared to their opponents in the post Versailles treaty era.

[@user-glg20]

I like your accent. It reminds me Arnie's "Get to the choppa! Now !!!" 😀

[@jeremystrain1574]

Interlocking will reduce some stress on the weld.normal seam from side all pressure will be on weld.interlocking could get by with less weld at cost of more material preparation.

[@busterdee8228]

Interlocking might tend to support plates in place during welding, tying up heavy fabrication equipment less. As to flat plate, it seems to me that you don't have to worry so much about shot traps or chaotic deflection. Trying to hit a turret ring would seem to be more challenging.

[@markir9]

I recall reading (can't remember the book) that **one** reason the Germans didn't use sloped armour was hull and turret space for crew flexibility and situational awareness. German tank tactics stressed teamwork (of tanks and crew) and this served them well despite their tanks being under armoured and under gunned at the start of the war. Contrast to French and British designs with thick armour but typically single man turrets. Similarly the T-34 was very cramped (single man turret and Crisper suspension reducing the hull space even more (the T-34/85 changed the turret and was a devastating improvement).

[@andrewklang809]

13:50 That transition from the FT-17 to the M3 Medium Grant/Lee puts a lot into perspective about just how much things had changed during the 1930s. While the FT-17/18 were WWI designs known to be outdated by WW2, they were still among the most numerous tanks available to the French in 1940, as well as Yugoslavia and Romania. Back then, a twenty-year old tank design wasn't anything to dismiss, and I say that knowing full well that 50+ year old tank designs are still being used in Ukraine today. Still, the teeny-tiny FT-17 versus the unwieldy-yet-solid M3 Medium shows that a tank from the 1910s that was born of cutting-edge innovation and a rushed design based mostly on already-disproved design notes on 1930s armor were still light years apart, with no war between them. The FT-17 was functional, but useless in a 1940s war. The M3 Medium was at least three times the size, and clumsy, and outdated at birth, but worked so well it was still in the front lines (in Burma and maybe New Guinea) in 1945. Two designs, barely twenty years apart. But you put them next to each other, they don't look like they could have ever been used in the same conflict. But they were. And neither was ever considered anything more than "good enough".

[@RichardCorongiu]

Just a suggestion...the interlocking loooks like a practical assembly idea. Just plonk this plate here...stuff in a spacer for welding gap...weld away...not much training , measuring, thinking ....without being there intimate ..thats posible ? If you had assembly drawings this would establish each asemblg step.

[@philosophyinthelight]

I believe it was a matter of metallurgy (in addition to other considerations such as increasing gun calibers on both sides). For example, the Tiger 1 and Mark IV armor had extremely high nickel and tungsten content with case-hardened faces that could shatter any Allied round...thus preventing penetration...with a milder steal core that absorbed the impact. Whereas the King Tiger and Panther factories could no longer obtain such high quality plates due to shortages of imported raw materials, and time constraints and the need for higher production, made multi-layer tempering impracticle...and therefore they had to switch to single-layer hardened but thicker armour that required sloping in lue of the earlier "samurai sword" multi-layered hardness tempering. This later armour (1943 on) was so thick and heavy that interlocking helped prevent shattering. In other words...German armour got thicker and sloped because the quality of the metal diminished as the war progressed...and the Panther often cracked at the seams after a few hits even with interlocking plates…