Thanks!

Thanks!

Thanks! I should have another one for you this weekend :)

hlaps1990 Looking forward to it!

All of the fasteners!

Thanks!

Yeah it worked out well! Prehardened with like 0.0002" of runout for $50 USD. Not bad!

Thanks! Now I just need some way of marking it so I can repeatably remove and replace it.

Except that there is no real way for repeat-ability when he takes it out and puts it back in. I would end up getting it where I needed it, removing the entire housing and drilling into it and then threading that with a pointed set screw to hold it in place concerning where it needs to be, though he will figure this out if this lathe ever starts to be used. um... also there is no grease seals on the shaft front and rear so if coolant is used that grease will become diluted and the bearings will go poof. Look at a trailer spindle and see how the grease seals work and also notice the good trailer spindles now use oil and not grease, and run much cooler due to this. Over all, very nice but I don't see it as a final version.

+yustech i appreciate that! More videos are coming!

+Toby W Ya i know SKF and NSK do too

Thanks! If you can't make something accurate, make it adjustable!

+charrontheboatman wise words. Its limited to around 3500 at the moment, but even then i plan on adding some guarding around the belt and index disc. I'll do a runout measurement at some point, though the runout of the collet chuck the spindle was machined out of is allegedly 0.0001", so I would anticipate most will be from the bearings

Thanx for such a promp reply, I would love to see the tech drawing or cads for this build if your willing to share them, I am specifically interested in ur mods.

Nope, you're not missing anything. You're certainly not missing an awesome name. The O-ring was a bit of an afterthought; you're absolutely right, a lip seal would have been better, my plan is to basically maintain a fairly low amount of grease that can pool in the bottom of the cartridge while not running, or get flung off into the bore walls while it is running. Next time. Next time will be better :)

You mean for alignment?

That's a good point. I'd certainly rather have 8 small fasteners over 4 big ones :P

Thanks for the tips Toby! Next time I use timing belts I'll try your tension trick! I think my next spindle is going to use a light oil rather than a grease, as you suggested

You're probably right with the cog belt. I see the tension was too high now, but I've since used a J section belt which is much quieter and works quite well.

Tabletop Machine Shop , I have also seen flat pulleys used with an inverted cog belt. It would likely float at high rpm. Cog belt with servo drives on spindle and carriage could be used for CNC threading.

I think just the lower speed and poor sealing. I think if I did it again I would do it with ball bearings and submerged in spindle oil, as you suggested.

I do plan on somehow marking the spindle so I don't have to keep adjusting it when I take it out for any reason -- maybe a nice brass arrow or something... A grease nipple would probably be a good idea, though I am trying to keep the grease coating pretty light (apparently too much grease makes things worse!). Perhaps in the next iteration I'll have a better seal and some kind of oiler. And, (last answer) you have astutely noticed a flaw in my grease seal ... it's a hair too thin for even the 1/8" wrench I custom cut for the job. Damn my decorative flair!

Yes, but at speeds below around 5000RPM. If the spindle were vertical, I would also expect that you would need better seals than the ones I came up with, because the grease or oil would pool at the bottom

+Y _ CNC its a 1" shank and about 5" long (i cut it down to around 4")

Well spotted. I have a very thin wrench :P

You're right, I'm sort of relying on the fact that the grease will either pool in the bottom and be contained by the O-rings, or fly radially off the shaft. So far it seems to have worked!

I like your project and your delivery :) Keep it up and good luck. Since you say you plan to make another one you might find this interesting. Emco V10 lathes have a similar angular roller bearing design but they do a couple of things differently (not to say correctly :)) All bearing races are press fit, you absolutely can't install the races with bare hands - I use an M8 screw and small spanners with one finger pressure to do the job. They run the spindle at max 3k RPM and they use hydraulic oil (sae 10wt/ iso 32 or iso 46) instead of grease. I'm not the bearing expert but 7k with large bearings and grease seems a lot to me. They keep the oil level beneath the outer race so it doesn't leak out from gravity, but the case also serves as a gearbox so larger gears fling the oil all over the inside and they lubricate the bearings like that. They have seals very similar to yours on the outside, except there's no o-ring. Instead there's a small hole in the lowest spot leading any accumulated oil back into the case - there's practically no oil leaking to the outside. It's hard to tell from the video but your preload seems a bit light. If memory serves torque of about 100g at 50cm lever (radially) from spindle should not move it from standstill but 120g should. That comes around to about 0,5Nm of static friction. I spin the spindle by hand while setting the preload, and the sound it makes changes when I hit about right preload. The other way to tell is spindle heat - about 30C rise above ambient is fine, more than that is too tight, less then that too lose. I don't know how that relates to grease and 7kRPM in your case. They also use plain nut with a setscrew - no nylock. Makes it a lot easier to install. A small brass disc below the setscrew keeps the threads from getting deformed.

It took a long time, but it was one of those cutting processes that looked so cool it was just fun to watch. I wasn't super keen on sticking an end mill out 2.5" on the Tormach, but on a larger machine that would probably be the way to go.

I was actually thinking about how that would look. I really like using those, it makes such a good top suface finish! Haha I definitely get mesmerized my milling at times, stuff ends up taking me so much longer than it should 😂

+Joel i'm working on drawings and a plan to release them, stay tuned!

I havent yet, but i'm hoping to get the pulleys finished soon!

More “a student of everything and a master of nothing” :p. Thanks though!

+Pete's Shredder. No theres a steel cup pressed into the aluminum :p

I think a witness mark would work -- like once it's aligned so I can put it back in repeatably? Maybe even a nice brass arrow or something...

+cnchobby1 thanks! Im using a ClearPath motor from Teknic. Its a CPM-MCVC-3441 ... theyre a bit pricey but they work great!

Its a race that's pressed in -- tapered roller bearings come in 2 parts, a cup and a cone, so I just pressed the cup into the cartridge.

I would recommend making the shaft as long as possible (reduce moment effects) and using ball bearings. Have a look at my jewellers lathe video on the spindle. Id recommend two angular contact bearings for the front and some kind of floating roller bearing for the rear. Id also recommend specifying a torque to tighten the preload nut to. I did it by feel, but over-tightening will kill the bearings, and under-tightening will ruin the surface finish. Let me know if theres any specific advice you need. My email is hlaps1990@gmail.com

Hi Mikael, sorry for the late reply. The end of 2018 was busy :P. I have looked very seriously at Tormach and Syil's spindle cartridge kits, but, since I have the tools at my disposal and I love what I do, I'm happy to try my own. It pains me to say it, but buying machines is usually less expensive in the long term. I would definitely look at Tormach or Sherline before you start planning your own machine :P. Feel free to email me (hlaps1990@gmail.com) if you'd like to discuss specifics! Greg

Hi @@TabletopMachineShop thx for your replay, I'll think I'll take the long version over mail :) Keep it up! Cheers!

@@TabletopMachineShop ...and would you consider trying to make an air bearing spindle next time for super precision and avoiding all the issues with lubricant (besides air) and (I guess) heating?

+somebody else ive since limited the speed to 3k RPM. My main issue here is that i wouldnt be able to retain oil, and even at 6 or 7k i think grease is acceptable. Youre totally right though, grease can make bearings overheat if theyre going too fast or even if you put too much in!

While replacing and running in spindle cartridges on a few machines in my past, I was taught by a friendly cartridge rebuild shop that the first few runs on a spindle are critical for grease displacement and bearing life. A newly packed bearing has grease in the way of the rollers that will get squished out, that grease squish-out friction will generate heat and warm the spindle. The idea is to mechanically throw/squish the grease out of the way but not allow the spindle to get warm enough to melt it and let it run off to someplace where it does no good. The grease needs to be moved out of the way of the main rotating bits but still close enough for surface tension to pull that thin film of oil from the globs all over the surfaces of the races and rollers. They recommended I run many low speed runs that last until the spindle gets warm, then stopping until completely cool, and repeat until the spindle does not get warm anymore. For example on a Toshiba VMC75 spindle cartridge, the spindle was run at low speed (300RPM~ish) for about 15-20 mins or until warm to the touch then allowed to fully cool. This was repeated a couple times until it could run the full time period without getting hot. The RPM were increased and the procedure repeated until full speed was achieved. The low RPMs took a while but once done it went quicker through the higher RPMS. I think all this run in business is typically done for you if you have a cartridge rebuilt for common/still current machine but since the VMC75 was of the early 80's vintage and the local shop did not have a jig to mount it to, the run in was done on the machine. Take that for what it cost you, this is not my area of expertise but it sure was fun. Good work and keep on making the videos.

Makes sense. I had to do a similar process to set the bearing preload on my ancient Atlas desktop mill and lathe. Everything is made out of rubber, and it all changes with the temperature...

Was thinking the same thing, ran a 20k rpm spindle at work and flood oiling was originally tried and the bearings were running way over temp, so oil misting was tried and no more problems.

+detoxrum yeah too many parts in general:p

I yelled at the screen "No don't do it!!!"

its so annoying watching videos and knowing that the mistakes have already been done!

Link to that video please? I thought I had watched them all, but I gotta see this...

Thanks!

Im planning on it! I need to figure out a way of doing it without powerpoint!

+ArcAiN6 i just open it up periodically and add grease manually

I have a very thin wrench :)

You're right: A setscrew is pretty weak for something like this, especially on a hardened shaft. Fortunately, the pulley is actually a shrink fit on the shaft, so that is transmitting most of the torque. The set screws are just there so I feel better :). The bearings can go up to around 7000RPM, however as another user pointed out, the rolling elements are so heavy that the acceleration is limited. The next spindle I try will probably have angular contact ball bearings. Thanks for watching!

​@@TabletopMachineShop By shrink fit you mean you made it slightly too small then heated it to get it on and when cooled it's i.d. decreased and tightly grips the shaft? But at 5:52 it's sliding on loosely. Did you buy a 2nd pulley and bore it out to make an interference fit?

I used a high pressure grease that I manually added before assembly. It seemed to work well, but an oil would have permitted higher speeds.

Yep I started at first turret and built outwards. Not the most efficient way of doing things :P

sanjay dubey i plan on doing more machining scenes as i go! Unfortunately for the first few videos i didnt take any footage when i was making the parts :(. Ive been taking a lot more now!

hlaps1990 Cool, I appreciate you for sharing your work. Could you suggest literature about how to design a machine like yours?

+sanjay dubey i like "Shigley's Mechanical Design" for all of the strength calculations, and the skf website has tons of bearing info!

Moar fasteners!

Can you build me a decent compact three axis CNC machine with a tool changer

+Bub Dog's What do you think? Agreed!

Phidgets*... Probably not the best company name for word-of-mouth

@@TabletopMachineShop well I know I saw the website in one of your videos but couldn't re find that video