Basic Carbide Codes, Feeds & Speeds for the Mini Lathe - Rob's Garage

Read this description here for 2 important updates to this video.
Join me on a 30 minute dive into my lathe cutting tools, insert codes, manufacturer codes, feeds& speeds and surface finish, all because I wanted to get some replacement carbide inserts for my lathe tools. I have simplified the process of finding additional varieties of inserts, what makes them different, and also just enough about feeds and speeds to know that you're doing things correctly. This is not a tutorial, but there is plenty to learn in here for a novice as you can watch me learning on the fly. There is some machining past the end of the video if you stick around.
Update #1
The smearing effect in certain cases was the result of using a bad/unknown piece of metal rod. One of the commenters below suggested this and he is correct. When I use a fresh free cutting steel, I no longer get this effect.
Update #2
I continue to use the carbide inserts now because the finish with fresh steel is excellent and is also improved by using the deeper cuts and higher speeds that I discovered to be suitable in this video.

[@Ducati900SS]

Check the description for a couple of updates to the outcomes of this video.

[@cpcoark]

Very good job of explaining these codes. Your video filled in a few gaps I had on the manufacturer's coding.

[@Ducati900SS]

Thanks Al, glad it was helpful!

[@timcook3539]

Highly recommend grabbing a copy of the engineers black book. Lots of reference charts to help navigate the insane complexity of carbide insert codes

[@Ducati900SS]

Thanks Tim! I've put one in my cart just now.. not cheap but is on sale :)

[@adhawk5632]

I did the same deep dive awhile ago, its worth it. It all makes sense in the end. Ive got the same lathe, this is great info. Dro's help heaps for this too, it changed the way i turn and face(and thread)👍👌🇦🇺

[@Ducati900SS]

Can't wait for the DRO.. !!

[@ww321]

I finally broke down and purchased a Diamond tool holder. It's the one I use the most now. Thanks for doing this great video based off your research . 👍

[@Ducati900SS]

heheh good one :) I'm still using the insert tools as well. After making this video I did the deep and fast cuts that the data I looked at suggested I should make, and the finish is excellent. Another important point someone else made is that the material I was using here might have been something junky and he was right. Soon as I used a fresh rod of free cutting steel, that smearing effect went away. Still going slow for parting though.

[@ww321]

@Ducati900SS oh I'm a fellow Ducati owner. Mine was bought as a basket case. 2000 748cc biposto . It was converted over to monoposto and they crashed it on the track. That seized the crank so I put a 1995 916cc in it. Fun stuff. I have a couple videos on it.

[@Ducati900SS]

Done.. subscribed and I'll go watch some videos while I'm working at my desk here :) @@ww321

[@ColinSpencer]

Thanks very much for a very clear informative video that de-mystifies some of the things I have found difficult to understand.

[@Ducati900SS]

And thank you for the feedback Colin!

[@bustednuckles2]

THANK YOU, FROM THE BOTTOM OF MY HEART!!! Like you, I am a relative novice and my eyes glazed over when trying to figure out all those codes, plus the feeds and speeds. I am saving this video in my favorites and am going to be referencing it and re-watching it many, many times in the future. Once again I can't thank you enough for deciding to tough it out and research these two topics, the inserts especially. Without a doubt you get a thumbs up and a subscription from me!

[@Ducati900SS]

Thanks knuckles! That is exactly why I did this and made the video. The main change I've made to my work since making this is that, with the insert tool, I will happily cut up to 1mm deep and at the 1250rpm limit of first gear (can't be bothered changing gears) and the cuts turn out very nice, better than in the video. Parting is still done slowly though. The other thing to note is that the material matters a lot. Another commenter pointed out that the unknown steel rod I was using could be causing the smearing and that turned out to be true. So now I'm careful to use a good quality known piece of rod for anything important. Anyhow.. I've subscribed to you as well!

[@StoryOfJames.]

I came for the bandsaw help but these lathe videos are fascinating!

[@deezworkshop]

Great video, I too am a master at the "Feels and Speeds" technique. This is a topic I definitely need to spend more time on. Subscribed!

[@Ducati900SS]

Thanks Deez... good to see you here :) That's a big fancy new mill you got there!

[@deezworkshop]

@@Ducati900SS Loving this new Mill so far. 🙂

[@dennissdigitaldump8619]

As for depth of cut, it's either deep enough the radius is all in, or you hit the groove in the insert, which matches your mathematical explanation. It's intuitive once you see the insert & it's geometry.

[@Ducati900SS]

Yes definitely. I've been kicking myself that I didn't do some additional deep and fast test cuts in this video after working out the feeds and speeds. Now I'm happy to do 1mm cuts at 1250rpm with these inserts and the finish is better than all of the tests in this video. Another commenter also pointed out that the steel rod I was using could have been crappy metal and he was right. I used an unknown rod for the tests here but when I tried later with a fresh free machining rod, it no longer caused that smearing effect. So at this point I'm sticking with the inserts as it is going very well, and I'm still too lazy to spend time playing with the HSS :)

[@trottermalone379]

Excellent video - useful information, thorough, well organized and presented! Question, any push-back from our Italian friends about using their logo???

[@Ducati900SS]

Thanks trott! What was the logo? oh... do you mean as the channel name? Hadn't thought about that... um pretty sure it's fine :)

[@user-oq7xg8jo5g]

Thanks for all the research you did Rob. Really helpful

[@Ducati900SS]

Thanks Jimbo - Much appreciated!

[@ChannelVideoTest]

I have the Optimum 2406 lathe, which should be identical to yours, just a bit longer. After some experimentation, I now exclusively use finishing inserts. The maximum capability of our small machines, in steel, aligns perfectly with the optimal conditions for finishing inserts. Roughing or even general purpose inserts often exceed the capability of small/benchtop lathes wich results in a poor surface finish and more wear. My main tool, a DCMT 070202 insert, has a specified cutting depth (ap) of 0.2mm - 1.5mm and a feed rate (f) of 0.05mm/rev - 0.2mm/rev. I use this insert for both roughing, with an ap of 1mm and a feed rate of 0.1mm/rev, and for finishing with an ap of 0.2mm using manual feed, so slower than 0.1mm/rev. I use isopropanol as lubricant. With this combination, the machine achieves even better surface finishes in steel than when using HSS.

[@adhawk5632]

Isopropanol seems to be a popular lubricant for non-ferrous metals too. I've got mainly CCMT and DCMT inserts, in 02 but no TCMT yet for the lathe, I'm still learning about all this, its my first lathe and tooling setup. 👍👌🇦🇺

[@myworkshop2]

Interesting video, well done.

[@Ducati900SS]

Hey Gazz, thank you!

[@FalcoGeorge]

Great Video Rob. Thanks. I’m just starting out myself in the same country. All this helps a lot.

[@Ducati900SS]

Thanks George! Make sure you subscribe.. I've just checked and all this work has only given me a single extra subscriber...It's going to make years to hit that 1000 at this rate, and there's only 14 to go! But otherwise, keep in touch and let me know how you get on.

[@GingerNingerGames]

Looks like I've got the same set of insert tools too. I was just working on a piece and experimented with upping the spindle speed and playing with the depth of cut, I arrived on 1250RPM and about a 1mm roughing cut. I feed the roughing cut by hand so I can manually break the chips because they're very stringy, but I do a final pass with the power feed at the same depth and the finish is good enough that I'm happy with it. I'll have to try that bit with the point straight out, looks like it does a very good job of breaking the chips itself, I'm currently using the tool with the edge square the the holder, I do need the square edge though, but for roughing the tip out bit will work well if it breaks chips the same.

[@Ducati900SS]

I tend to use that one where the edge is just a little more than square with the holder, mainly because I don't need to change tools for facing. I haven't actually checked to see if the chips change when the angle changes like that. I've been less worried about chips than I was at the start, after I realised that it's more about convenience and perhaps some safety as well. I should consider it more though.

[@dennissdigitaldump8619]

I had a friend give me a Seimens tool catalog. It had many pages explaining inserts like this. And they list ISO first as most of the machines are imports.

[@Ducati900SS]

I'm much more on the ball about this now too. I should have guessed straight away that that ANSI inserts chart was the wrong one. Took me 3 visits to realize it!

[@tomeyssen9674]

Thank you for this. The ansi/iso thing has often driven me crazy. I often wonder if the variations in mild steel are also due to compound flexing in relation to the carbide nose radiues and sharpness. Thanks again.

[@Ducati900SS]

Hi Tom. I think Carbide definitely does more of a scoop whereas steel sort of shaves the metal off. Carbide would seem to need an extra push to get started, which may cause flex at that point. The compounds definitely flex within the dovetail. Because of this I've since added some extra gib screws to my compound , both to adjust the slide and also to lock it up when needed. I'm not 100% sold on needing total rigidity at all times, but at least it gives me a little extra. I'd need more experience with different steels to know more. I've basically got some junkyard steel rod and some brand new free cutting rod here, and I failed to use the new rod in this video. I didn't think it would be different until someone commented below. Then I tried it and it was. Since then, using fresh steel and high speeds (900-1250) with my little carbide tools has worked out well, except for parting which I still do very slowly.

[@bin_chicken80]

I know this is from a a while ago but surely there is some sort of application where you can scan the barcode on the package and get all the exact characteristics of that particular insert. It seems crazy that you you would need to go to this length and figure this out manually.

[@Ducati900SS]

Yes, totally agree. The entire topic is crazy and seems impossible to manage. I actually downloaded the Kyocera app before I made this, but it was just too complicated because you still have to know what it all means in order to use it. And that is exactly why I made the video here. Now I know how to ignore 99% of the information and find just what works with the tools I've got. It was certainly a scary topic when I first got my lathe, but its ok now I've done the work in the vid. I think an app could be made to handle the standard ISO/ANSI part of the code system. But when it gets into the manufacturers codes, it would become too complicated, unless the manufacturers all agreed to do it together... fat chance of that happening :)

[@stefantrnacek1394]

Very interesting and informative video. I will have to look up those charts. Do you think using or not using coolant would also have an effect?

[@Ducati900SS]

Hi Stefan - Since starting this hobby I've tried the watery type coolant (basically water plus a light oil), a light oil/kerosene (CRC) and also a thicker cutting lubricant. I've settled on the CRC for aluminum because it keeps the insert from getting clogged, and the thicker lube for steel. I would use the watery coolant on the mill for longer and hotter cuts.. I don't see any significant variation in finish with either of the fluids and even dry cuts... which I put down to the light cuts I do (they are short and seldom get hot). But after making this video I will be going in harder and that may show up more significant differences. I've also been thinking about that smearing effect from the two gold inserts in this video. I'm going to test them at much deeper cuts to see if it is the shallow cuts that causes that issue. The fact that the silver insert with the sharp edge doesn't do it seems like a good clue. Thanks for the positive comment too!

[@stefantrnacek1394]

@@Ducati900SS I look forward to seeing the results. I will try the CRC next time I am doing Aluminium.

[@Ducati900SS]

​@@stefantrnacek1394 Cool. Note that the CRC I'm referring to is the kind that is the same as traditional WD40.. the oil/kerosene type. They make so many new types, including the silicon ones that wouldn't be suitable. Some people even use straight kerosene but I like the convenience and safety of the folding plastic applicator straw. They also do them a little cheaper but with that tiny white straw that falls out all the time. Also FYI - I was watching one of Stefan Gotteswinter's videos just now and he was doing all his small cuts totally dry with perfect results. He also made a comment about how the insert he had required a specific minimum cut depth otherwise it gives a bad finish. That seems to agree with what I've been thinking. So I'll definitely investigate that.

[@stefantrnacek1394]

@Ducati900SS thanks for that info.

[@grunnax]

Cermet is a TItanium Based Carbide instead of Tungsten

[@fearlyenrage]

and maybe get some SUMITOMO TNMG160404N-FA T1500A they are made for softsteels and outstanding finish.

[@Ducati900SS]

Thanks Fearly, I have put that code in my notes for next time!

[@fearlyenrage]

@@Ducati900SS we use them prior for soft steels. They work magic!

[@joansparky4439]

Mine arrived a week ago. Nice machine overall. Saddle lock seems to have the same issue of not tightening down, so gotta check that. First had to make some parts.. which is done for the moment - change gears are a PITA - have to do something about that sometime ;-) I noticed on mine that the cross-feed dial is marked as 2mm per turn, but the leadscrew in there only has got a pitch of 1mm.. ?!? The other thing that bugs me is the saddle-feed with 25mm per turn, which is rather fast for such a small machine. I'll probably modify both of those things down the road (already working on plans in CAD) to have the cross-slide on 3mm / turn and the saddle at 10mm / turn.

[@joansparky4439]

PS: thanks again for the measurements some time ago.. the magnetic digital scale arrived and will fit nicely on the saddle without reducing swing or other.

[@Ducati900SS]

They need to fire that person who does the saddle lock! The 2mm on that knob is off the diameter of the workpiece. I've found that and the compound dials both give me very accurate results. I've not used the saddle dial for measurements and only use it for moving the saddle back and forth. When I install the DRO I have for the lathe, I'm going to combine that and the compound together into one axis. I've had the thought in the past to add another cog into the saddle to give that dial finer control and to remove some of that slop in there. Did you find any issues with the saddle racking across opposite corners when not locked? A couple of others had that and it'd be good to know how common this is. Also - what's the reason or logic for making the cross slide 3mm per turn? Is that just to be finer or for a specific function?

[@joansparky4439]

​@@Ducati900SS oh, diameter.. ups 😳 OK, then it's correct. 🤭 The saddle on mine seems fine for the moment, no rocking as far as I can tell. But no idea what happens when I unscrew the gibs/clamps/etc. Sliding wise everything is pretty good, so I don't expect any surprises there even without it being held in position by those parts?! As for 3mm.. economic trapezoidal left hand lead screws come either in 2mm pitch for 10mm dia or 3mm pitch for 12mm dia.. and bigger is better in this case and per my measurements a 12mm dia will fit in there. And 3x faster cross slide movement sounds about right.. it's too slow for me now. Oh.. that rack-gear is NOT well aligned to the bed - leans backwards by ~5deg - there seems to be some of that putty for smoothing out holes/etc. under there too. Plus the pinion only engages for 1/3rd of the teeths width which wont help with longevity?

[@joansparky4439]

@@Ducati900SS PS: be aware that adding a single pinion reverts the turning direction of the gear-train this goes into. The convention for lathes seems to be that turning the hand-wheel to the right, moves the carriage to the right. If slop I would investigate how the rack/pinion meshes and if the rack can be moved a bit.. I found that it's mounted in a position that works for lathes where the handwheel / half-nut lever are inverted to what we got. If wound to the far right the rack nearly disengages the pinion.. so re-aligning the rack with new holes for the screws a couple centimeters to the right is possible. The other things that potentially offers adjustment is the handwheel mounting sleeve that is bolted to the apron and which works as a bushing for the handwheel axle.. maybe that can be moved so the 14T gear meshes better with the 44T gear that drives the pinion to the rack?

[@Ducati900SS]

@@joansparky4439 Ok that's good to know the rocking isn't a standard feature :) And that's interesting about the lead screws. You have some work planned that we will want to see later on! Hope it's still going well there :)

[@fearlyenrage]

Hi You could make a kzbin.info/www/bejne/p4nQfaumiL-DnLc tool. And chechout grinding and turning between center that delivers endgame finishes!

[@Ducati900SS]

Oh yes, I've been looking at a few videos on those lately and have already got a design in mind for one.. will definitely do one!

[@dudemann.]

what brand of qctp is that?

[@Ducati900SS]

Hi dude! It's called a Multifix and conveniently, I have a video on it. Check it out here and get back to me if there's anything I can add: kzbin.info/www/bejne/fXmVeX6patOeqqM

[@dudemann.]

@@Ducati900SS Thanks for the reply. I did however find your video righjt before you replied. That thing is rather pricey.

[@Ducati900SS]

@dudemann. yes, it's definitely not cheap. Even worse when one buys the Type A version first by mistake and then has to sell it to get the Type AB.. erk!