ZX 7045 Mill Head Upgrade - Part 4C New Quill Pinion Shaft (Gear Cutting)

In this video, we conclude the pinion shaft manufacture and get the mill back together again. Quite a bit going on in this one!
Channel artwork: Ryan Toomey

[@paulrayner4514]

great job John, one question out of curiosity, when you clocked the bore before machining for the bushing ,how come you didn't clock the face, or did you but didn't show it?

[@jonsworkshop]

Hi Paul, thanks for the comment and great question. The front face was not the location face into the head casting, that face was up against the front of my jaws which I know are good so I didn't bother in this instance. The bore was very short as well so any error off the front of my jaws would be miniscule over this length. All thought processes I go through but don't always verbalise to keep the videos to a reasonable length, so thanks for asking this. I will pin this comment at the top for others. Cheers, Jon

[@paulrayner4514]

@@jonsworkshop Ahh. I see now, I thought it was the other side with there being a rebate as such. thanks for the reply.

[@bobuilt10]

Glad the spline worked out this time Jon. As an apprentice we used to do quite a few splines for the machine repair team, we were taught to blue the end of the shaft and test run our dividing hole plan by scribing lines with a height gauge. This did two things, it allowed you to check the spacing was perfect by finishing back on the first line, secondly you could keep a check on each cut to ensure you hadn't wondered off the line as can easily happen when using dividing fingers.

[@jonsworkshop]

Hi Andy, thanks for the comment. Yep, great teachings, I wonder if modern apprentices are getting the same experience. I realise the world has moved on and Manufacturing is completely different these days, but some of the grounding around checking and problem solving is a critical underpinning of a good engineer in any industry. Cheers, Jon

[@TheAyrCaveShop]

I like it !

[@seamusbolton215]

Well done, I think this calls for a couple of pints of Guinness to celebrate

[@jonsworkshop]

Hi Seamus, thanks for the comment and feedback. I think you are right lol. Cheers, Jon

[@terrycannon570]

Jon I really enjoyed this project. Using the Delron test is a great way for a sanity test. Thanks for the explanation on the dividing head. I have the same dividing head. I am certainly looking forward to the future usage of storage. With a 12' x 12' shop, space is always a top priority for me as well. I am currently building a combo rolling worktable/lift table for getting vice and rotary table off my mill. I no longer drink but please enjoy a cold drink on me. Thanks for bringing us along.

[@jonsworkshop]

Hi Terry, thanks for the comment and feedback. Glad you are enjoying the content. Space is always a challenge, no matter how big your workshop is, you will always expand into it plus about 20% lol. Not sure how I am going to tackle mine yet, it needs some thought and planning. Thanks very much for your kind gesture, I will put this towards the workshop for either storage, camera gear, tooling, materials etc to help me make more and better videos, much appreciated Terry. Cheers, Jon

[@jerrywilson9730]

Great! As always enjoyed. It looked like, from the camera angle, when you drilled the larger hole, the drill seemed to flex. How about a video on what happens when the bit flexes and what to do about it. Keep them coming, and thanks.

[@jonsworkshop]

Hi Jerry, thanks for the comment. Very observant, of course what you couldn't see off camera is that some fool forgot to lock the tailstock up lol, that's why I retracted and came back in for a second go. Also, the drill was brand new and very long meaning more leverage to influence the loose tailstock, so the combination of both things caused what you saw in this case. Cheers, Jon

[@Steve_R]

Bit of a journey Jon, but you got there in the end. Well done. For storage, when the time comes, I plan on using a french cleat system on the walls. Spaced about 6 to 12 in. (15 - 30 cm). That way everything is adjustable as my needs change or new tooling is acquired. Its cooling down here in central Canada. Won't be long until its covered in white stuff for 6 months. Take care, Steve

[@jonsworkshop]

Hi Steve, thanks for the comment and feedback. Yes, time for a big rethink in the workshop, not sure what I will do yet, but I need to get a lot of stuff off the floor and up on the walls so shelving, French cleats etc. Cheers, Jon

[@carlwilson1772]

That was great Jon, I really enjoyed it. A brilliant outcome. I don't see the first attempt as a mistake. These things are largely experimental and iterative processes. A great result.

[@jonsworkshop]

Hi Carl, thanks for the comment and feedback. Glad to have the machine back together, it has enabled me to be 'experimental and iterative' again today lol, I will let you work the rest out🤣🤣🤣👍. Cheers, Jon

[@swanvalleymachineshop]

If it looks right , it is right ! Interesting with the backwards indexing , never heard of that one before . 2 & 18 on a 21 plate will work as well . Amazing how much we forget from our apprentice days , helical milling , gears , worms , saw tooth clutches etc👍🍺🍺🍺 .

[@jonsworkshop]

Hi Max, thanks for the comment. Yep, I never did any gear cutting in my apprenticeship, did mine as a toolmaker so it was predominantly punches, dies and die sets. Never too old to learn though lol. Cheers, Jon

[@swanvalleymachineshop]

@@jonsworkshop Toolmakers apprenticeships were nearly impossible to get back when i did my one , so fitting & turning it was !

[@bhein67]

I have quite enjoyed this series of videos and learned a lot. Thanks again for sharing! I am looking forward to your testing of face mill cutters. Having recently acquired a new mill, I am learning how to use a face cutter and getting a proper finish with a face mill (sorting feeds and speeds are still a mystery to me). Seeing your organizing solutions will also be helpful as well. Cheers from Canada

[@jonsworkshop]

Hi bhein67, thanks for the comment and feedback. Lol, don't hold your breath on the face Mills, you really need a Bridgeport or bigger to use these effectively, so I already know my machine will struggle, especially on steels. Yeah, I need to do some proper thinking on the whole storage thing, I will of course share what I come up with. Cheers, Jon

[@philflip1963]

All safely gathered in, Phew!

[@jonsworkshop]

Hi Phil, thanks for the comment and feedback, much appreciated. Cheers, Jon

[@Man-in-da-shed]

A fitting end to the series, I’m very interested to see your take on making space in the shed, a subject dear to my heart.

[@jonsworkshop]

Hi Ian, thanks for the comment. Lol, you are the only thing that keeps me sane! When I am getting all fed up that I am in a right mess, you remind me that there are others out there with bigger problems lol! I am sure you will take my humour as well meant 🤣👍. Cheers, Jon

[@Man-in-da-shed]

@@jonsworkshop oooh. For that I am royally going to take the mick out of you. In a nice way of course.

[@jonsworkshop]

@@Man-in-da-shed Ha haaa, open season, looking forward to it! 🤣🤣🤣

[@Man-in-da-shed]

@@jonsworkshop first blood tonight. Lol

[@wibblywobblyidiotvision]

Excellent work, Jon. Good to see the quill back and functional.

[@jonsworkshop]

Hi Wibbly wobbly, thanks for the comment and feedback, much appreciated. Cheers, Jon

[@TheKnacklersWorkshop]

Hello Jon, Well done for completing the marathon - lol... in a strange way I feel sure this has renewed you confidence to tackle anything from now on... Take care. Paul,,

[@jonsworkshop]

Hi Paul, thanks for the comment. It initially kicked my confidence in the backside, but yes, on completion, fully restored lol. Cheers, Jon

[@TERRYB0688]

Jon, brilliant job pal, bit of a learning curve but persistence won the day, I’ve learnt a lot from these episodes, never done any work cutting gears, have a rotary table but no indexing facilities. That seems a nice one 👍👴🏻

[@jonsworkshop]

Hi Terry, thanks for the comment and feedback mate, much appreciated. Nice to only have the one machine in bits again instead of two lol, it was getting a bit overwhelming. Cheers, Jon

[@MrFactotum]

Lovely Job Jon a lot of work but well worth it, all part of the fun though see you next time cheers Kev

[@jonsworkshop]

Hi Kev, thanks for the comment and feedback. Yep, happy to have got that one behind me lol. Cheers, Jon

[@meawayfromhome]

Hi Jon, top job mate, very happy it turned out well for you! Though it was never in doubt.

[@jonsworkshop]

Hi Philip, thanks for the comment and feedback, (and confidence lol) much appreciated. Cheers, Jon

[@GoCreatehms]

Beautiful job! Gear cutting is always very satisfying.

[@jonsworkshop]

Hi Nigel, great to hear from you mate, hope you're well and thanks for the comment and feedback. Cheers, Jon

[@gregwmanning]

Great recovery and excellent result

[@jonsworkshop]

Hi Gr eg, thanks for the comment and feedback. Cheers, Jon

[@andrewdolinskiatcarpathian]

Hi Jon. Thank you for another interesting and informative video. So good to follow your prove and progress. Coming along nicely. 👏👏👍😀

[@jonsworkshop]

Hi Andrew, thanks for the comment and feedback, much appreciated mate. Cheers, Jon

[@matspatpc]

Nice work! Looking forward to seeing more work with the updated mill. I know the feeling for tripping over things all over the place.

[@jonsworkshop]

Hi Mats, thanks for the comment, yup, you know when it's bad when you can't find what you had in your hand 2 minutes earlier lol. Cheers, Jon

[@tonypewton5821]

Nice one Jon, fantastic job! I enjoyed this series, great to see the machine all back together and working! 👍 Regards Tony

[@jonsworkshop]

Hi Tony, thanks for the comment. It certainly is, it was getting a bit overwhelming having 2 machines in bits at the same time lol. Cheers, Jon

[@MattysWorkshop]

Gday Jon, the shaft turned out perfect, I wouldn’t say it’s was a cock up on the original shaft I’d say it was a learning curve, the amount of learning you had by building the new one was worth it, im keen to see the organisation solutions you come up with for the workshop, im slowly running outa room here as well, brilliant job mate as always, cheers

[@jonsworkshop]

Hi Matty, thanks for the comment and feedback. Yep, it's turning into a $hit hole in there, I hate being in a mess. May need to take a KZbin sabbatical for a couple of weeks to get my house in order lol. Cheers, Jon

[@davidbawden6567]

Great job Jon, beautiful finish to the shaft as well...

[@jonsworkshop]

Hi David, thanks for the comment and feedback, much appreciated. Cheers, Jon

[@bostedtap8399]

Great job all round Jon, spline finish looked 👍 Great. Thanks for sharing 👏. Best regards John

[@jonsworkshop]

Hi John, thanks for the comment and feedback, much appreciated. Cheers, Jon

[@knightrideruk]

Great stuff Jon plenty more like it please.

[@jonsworkshop]

Hi John, thanks for the comment, I'll try my best lol. Cheers, Jon

[@markhollinshead4153]

Great video Jon, I really liked seeing your processes on making this part. Top results too is always a bonus

[@jonsworkshop]

Hi Mark, thanks for the comment and feedback, much appreciated. Cheers, Jon

[@MyLilMule]

You had to take the long way to get there 😉 but it looks like you still had a lot of fun. And now you have a 30 taper spindle that's so much better. Although, I will say, I was hoping to see the shaper put to work on the rack. LOL. Well don, sir, well done.

[@jonsworkshop]

Hi my lil' mule, thanks for the comment and feedback. Loads of fun and learning lol. The shaper is on the horizon again now I have the mill back up and running. Cheers, Jon

[@TheAyrCaveShop]

Jon, Fantastic well done, a nice conclusion to part 4. I'm sure your happy to have the mill back in one piece. I have the same organization / space issues...constant battle to save or reclaim any inch or two of space. Enjoyed.. ATB....Dean

[@jonsworkshop]

Hi Dean, thanks for the comment and feedback. Yep, very pleased to have the mill back fully operational again, just down to the one machine in bits now lol, I must get back onto the shaper project. Cheers, Jon

[@watahyahknow]

if the quill is still a bit tight you can use some prusian blue on the gear and look for wearpoints , it might be that the teeth are good but you need to wittle the circumference down a little with emery cloth as it touches the valleys in the rack part just thought of sumting , the part you had put the brass bushing in mightve been made offcenter on purpose , the way you can somewat adjust the dept / mesh of the teeth between the rack and gear by rotating it a 1/3th turn as for storage : might want to put shelves up around the circumference of the shop over the cabinets and machines for the lesser used big parts and smaller bit and bobs stored in bins , the shelves can allso make a hanging mounting point for the camera using a clamp , a dailholder type clamp / tripod camera type mount mount and some barstock so it floats over the top of the machine , should be less in the way than using a tripod , bunch of hooks screwed in under the shelves alows you to hang stuff under them too

[@jonsworkshop]

Hi Watahyahknow, thanks for the comment and suggestions. The cast iron bearing was on centre, it was just really badly made I think. Someone did suggest eccentric bushings both sides to actually fix the problem without the need to recut gears. It was an excellent suggestion, if I had a way of machining the head casing for the big bearing diameter, I would have probably gone down this road. Cheers, Jon

[@Steviegtr52]

At last a result Jon. Hope the machine now goes on to greater things. Regards. Steve.

[@jonsworkshop]

Hi Steve, thanks for the comment and feedback. Me too. Cheers, Jon

[@trollforge]

Glad to see you finally got it done!

[@jonsworkshop]

Hi Trollforge, thanks for the comment and feedback, much appreciated. Cheers, Jon

[@dermotkelly2971]

Great job John! I had a job like that years ago on a pinion gear and it was tight and it took me ages because I was taking off 3 thou at a time! I must have taken 10 cuts at 3 thou a time lol

[@jonsworkshop]

Hi Dermot, thanks for the comment, yes, it can feel inefficient at the time but getting it right in the end is worth the effort. Cheers, Jon

[@dermotkelly2971]

@@jonsworkshop I probably never worked out the depth of cut properly because I never did gear cutting at all

[@eyuptony]

Good point using shim stock in the lathe jaws Jon. I've never liked copper for repeatability if it compresses. Superb job enjoyed watching. really pleased it's worked out well. Tony

[@jonsworkshop]

Hi Tony, thanks for the comment. Yes, I was taught the shim stock trick by an old toolmaker many years ago, it works a treat. You can even use it to centre parts in a worn chuck by altering the thicknesses used under each jaw. Cheers, Jon

[@eyuptony]

@@jonsworkshop Top Drawer reply to an industrialist have a go novice lol. Cheers Jon, Tony

[@davemason6273]

Awesome job John, that lathe's a cracker. Cheers

[@jonsworkshop]

Hi Dave, thanks for the comment and feedback, it certainly is, one of my better investments lol. Cheers, Jon

[@joell439]

Nice job- can’t wait to see what you have in store next 👍👍😎👍👍

[@jonsworkshop]

Hi Joel, thanks for the comment and feedback, much appreciated. Cheers, Jon

[@daveticehurst4191]

Well Done Jon. Got there in the end. Regards from Australia.

[@jonsworkshop]

Hi Dave, thanks for the comment. Yup, persevering and being well equipped being the two things that got me through 👍. Cheers, Jon

[@Just1GuyMetalworks]

Now that's a proper shaft 😊. Great job! 👍😁👍

[@jonsworkshop]

Hi Just one guy metalworks, thanks for the comment and feedback, much appreciated. Cheers, Jon

[@Machine_NZ]

Hi Jon, nice work and a success this time. Good idea to use a piece of Delrin for a trial run. Regards Kevin

[@jonsworkshop]

Hi Kevin, thanks for the comment and feedback. Yep, I would probably not have bothered with the test part (even after having been bitten once already) were it not for the comments from the community that made me step back and think! Cheers, Jon

[@TrPrecisionMachining]

good video jon..thanks for your time

[@jonsworkshop]

Hi Tr, thanks for the comment, much appreciated. Cheers, Jon

[@Rustinox]

The little upgrade became a big undertaking, but it all ends well.

[@jonsworkshop]

Hi Rusti, thanks for the comment. Yes, made bigger by my own stupidity but we got there in the end lol. Cheers, Jon

[@graedonmunro1793]

g'day jon what a good vid thank you, never seen a depth mic used that way before but i will remember it. cheers

[@jonsworkshop]

Hi Graedon, thanks for the comment. Yep, standard practice in aerospace to check turned drops with a depth mic, takes a bit of feel and practice but is a very good method. Cheers, Jon

[@stevechambers9166]

Great job Jon weird lndexing but works perfect if you follow the instructions 😂thanks for your time

[@jonsworkshop]

Hi Steve, thanks for the comment and feedback. Yep, just had to remember how to count holes and everything was gold lol. Cheers, Jon

[@TheOnlyMosesMalone]

Lovely job Jon, been looking forward to this one!

[@jonsworkshop]

Hi Morgan, thanks for the comment and feedback, much appreciated. Cheers, Jon

[@geoffrobinson5584]

Great job Jon! Great video's too - I'm learning lots, keep it up.

[@jonsworkshop]

Hi Geoff, thanks for the comment and feedback, that is payback enough for me. Cheers, Jon

[@retromechanicalengineer]

An excellent component Jon, it's a credit to the work you have put in. Best wishes, Dean.

[@jonsworkshop]

Hi Dean, thanks for the comment and feedback, much appreciated. Cheers, Jon

[@allenhunt3070]

Nice video Jon.

[@jonsworkshop]

Glad you enjoyed it Allen. Cheers, Jon

[@josephlovell6951]

Well done glad you got itall done. And it works

[@jonsworkshop]

Hi Joseph, thanks for the comment and feedback, much appreciated. Cheers, Jon

[@brandontscheschlog]

Nice work! Love the channel

[@jonsworkshop]

Hi Brandon, thanks for the comment and feedback. Cheers, Jon

[@trevorjones4463]

Well done mate I had to cut 2 gears ⚙️ so went around to a mates you no him matty of mattys work shop easy on his sinsnaty mill and him making sure I didn't stuff it up haha 😉 😆

[@jonsworkshop]

Hi Trevor, Thanks for the comment. Matty is a great bloke, he would certainly not lead you astray! 👍. Cheers, Jon

[@bearsrodshop7067]

Jon is now a Happy Camper,,,Applause deserved and a triple thumbs up :)>. Amen to reorganization as well here (@@)! Sammie sent me a message,,,Pick up and quit tripping over cords and tools :(

[@jonsworkshop]

Hi Bear, thanks for the comment. Lol, it wasn't without its problems but we got there in the end. Cheers, Jon

[@delstone1919]

Haaaaaaaaa, an excellent video Jon. I have to give you a GIRTT for that.

[@jonsworkshop]

Hi Del, thanks for the comment. Lol, living under a rock as I do, I am going to have to look that one up😂😂. Cheers, Jon

[@delstone1919]

@@jonsworkshop Got It Right This Time

[@jonsworkshop]

@@delstone1919 I can be a lemon sometimes lol. Thanks Del

[@christophercullen4889]

Jon thanks to KZbin creators I have been able improve my workshop techniques , This week I watched a Joe Pie video on shaping HSS for my flying cutter . I still have trouble power taping on lathe and mill , I create perfect ream holes. Would it be possible to do segment on this technique ? Old apprentices for Down Under

[@jonsworkshop]

Hi Christopher, thanks for the comment. Just to clarify, on power tapping in the lathe? If so, I will cover in a future tips video. Cheers, Jon

[@christophercullen4889]

@@jonsworkshop yes Jon that would be appreciated.

[@hogan6216]

Well Done A+...

[@terrycannon570]

Thanks!

[@jonsworkshop]

Thanks Terry, much appreciated indeed. Cheers, Jon

[@PeckhamHall]

I don't know if this will end well? Fingers crossed 🤞

[@jonsworkshop]

Hi James, thanks for the comment, much appreciated. Cheers, Jon

[@chrisstephens6673]

Don't look on the original, er, "error" as a mistake but as an opportunity to get that great sense of satisfaction by creating a whole new one which is probably better made than a "store bought" one. Don't you just love thst chuffed feeling when things go right. With you tube going on about channel name changes to make one more identifyable, i was thinking of changing mine to "I've learnt enough to get it right first time, occasionally " ATB c

[@jonsworkshop]

Hi Chris, thanks for the comment. Ha haaa, I am very self critical, obviously the footage was incredibly cleaned up for viewer delectation, if I had broadcast the 'real time' reaction, I think I would already be in a back to front jacket staring at soft walls lol. Love your channel name, go for it, brilliant! Cheers, Jon

[@chrisstephens6673]

@@jonsworkshop" brilliant " that sounds like flattery and I should warn you flattery doesn't work on me anymore, I'm too used to it.🤣🤣🤣

[@ryannaudi4067]

Hi,what is the modulus of the gear?

[@camillosteuss]

Recently found your stuff, and i have to say, the indicator stand of the old style is indeed great for lathe and mill clocking in some arrangements, but what bothers me is that your lathe somehow has enormous tool deflection or something... A few setups were forced on you by the geometry of the projects and of course, spontaneously induced chatter and insert holder vibration, but here, you are cutting brass on the side and you have so much deflection that a screw finish was made on the return pass before parting operation... My baby lathe uses 10mm shanks for holders, well, she can use 15mm but i wanted to get a small set as 15mm boring bar is no good for small part work... Sure, i made my own smaller and larger boring bars and what not, but she, for a baby lathe which weighs 150 pounds, she by all logic should provide more chatter and deflection of any and every form, compared to your much larger lathe... Sure, my big girl lathe has a 150 pound tailstock, but the baby lathe should by all logic be inherently much more gentle and less rigid... And i dont get chatter or tool deflection with carbide inserts on her, in bloody stainless steel... Let alone brass... Ok, she is from 60`s or early 70`s and is scraped in all over and is made in image of other small precision lathes, like the swiss mikron baby lathes or similar designs(theres a lot of that style replicas all over the world)... That can be accounted for in the rigidity department, and the surfaces geometry and relations sure add stability to her ``body parts`` but her tools are still on 10mm carbide shanks in an old style 4way toolpost on a compound slide, some of which renders rigidity, some of it which denies it... The 4way is very rigid, unlike most cheap qctps, but compounds are always a source of potential loss of position... I wont say that the big girl is rigid as the core of dead stars, as she kinda has to be... She is almost 3 tonnes, but your lathe should by all considerations have the inherent material capacity for greater rigidity than a much smaller lathe... Of course, your parts fit on the lathe can make or break the deal, and that is why my baby lathe is oem scrape-matched all over, but i would definitely check your lathe and all of its parts fitments with machinist blue, each against other, then on the s. plate... After that, when assembled, inspected with an indicator as to ascertain the potential play after the fits are well detailed and geometries printed against each other... That will give you a clue where your major loss of rigidity comes from... I would denounce that qctp of yours, as its the most obvious thing, after the compound side, but that is preconceived notions, which arent any basis of good and proper precision work, or care for machinery.... Take a week and check every part against its mating surface and for wiggle of any kind, that will instantly inform you what is the problem... Hell, you could have a loose carriage gib on one side, operators most likely in this case, so its really hard to make a good educated guess... Only a micron indicator will speak with certainty, i can only speculate...

[@jonsworkshop]

Hi Camillo, thanks for the detailed comment. What you are seeing is a tiny amount of deflection (which all lathes have regardless of size or quality), and the majority is uncut material. When you use carbide insets with radii on the corner (in my case 0.8mm), and you feed hard to break the swarf which I do, the resultant surface is very scalloped (cusped), with high spots on a spiral coincident with your feed rate. When you then wind the carriage off in reverse, you cut all the high spots leaving the spiral you saw. The true test of lathe rigidity is parting off, you will see in some of my other videos I can push a 5mm wide parting insert through carbon steel at high rpm with no issues. I did a full check on this machine when I bought it and it is in really good shape. Chatter and vibration is more often than not caused by incorrect tool geometries which is very true in my case as I tend to be a bit lazy swapping tools over when I know I should etc. Cheers, Jon

[@camillosteuss]

@@jonsworkshop Damn, 0.8 is quite the radius... I understand chip formation and breaking, and the nature of carbide vs hss tooling, as i am a machinist myself... Interesting... I usually keep my cuts on both lathes, small and big, below or around 1mm diametrically, which on both lathes results in decent chip control(mostly) and slightest hint of back drag on the baby lathe... Tho, i use strictly tools and inserts with minimal radius, as i tend to avoid excessive material removal if the design geometry doesn`t demand it... The big lathe can take immense cuts and i do use ceramic and cbn round and square inserts and carbide with large radii when i need them, as she can manage any loads or cuts... She is a beast of 3 tonnes afterall... Yeah, i agree, your parting performance does indicate high rigidity of the whole system, but i don`t really ever have that much of deflection on either lathe... It could merely be up to style of the operator, as i rely on other machines aswell for some aspects of work, so it could just be that, the operator`s approach and tool selection... Avoiding large radii and sticking with sharp and tight edges along with slow feed and relatively deep cuts allows me to reduce tool pressure and in turn any thusly induced deflection of either part or tool. If i need superb finish, well, that`s what a polishing lathe is for, or even the t&c grinder for some small parts, as deckel s1 has a wide range of approaches that it offers to grinding... I guess i tend to approach turning like i do grinding, which is with relatively slow feed along with higher spindle speeds... That generally breaks the chips and leaves a good enough finish for most non precision parts... Roughing work i do by handfeed, as its often a single or few passes, and it allows me to ``feel`` the material through the system...