Build Thread- The "Parts Bin Micro Lathe"

[Jason3]

I felt it's about time I posted a build thread - here it is...

I've wanted to do this for a while - build a (very) small lathe, mostly just for fun but also to test aspects of a similar design I'm working on. This machine will have a work envelope of around 50 mm x 150 mm - a 2" x 6" lathe if you will. It'll run ground 2 mm pitch ball screws, Nema 17 brushless servos, with a servo spindle drive also. Initially gang tooled, a turret will hopefully follow later. I'll be aiming for good accuracy and surface finish, while maintaining the ability to take a decent cut (relative to the size of the machine of course...)

So, here's the obligatory first pic:

[SpeedsCustom]

Looks small but very solid. I mean, I know it's small. But looks good!


-Jason

[LeeWay]

Ah. There it is. That size would cut out the parts that I have to make with my new build. Lots you can do with one that size. Look what guys do with the little Sherline lathes.
This one looks a lot tougher though.
Look forward to hearing more about it and finally watch it spin some stuff.

[Jason3]

Thanks Jason and Lee!

Looking back, this lathe will be big enough to do 90% of the things I've used my manual lathe for in the last couple of years. It'll require a bit of creative fixturing for parts too big for the ER32 collet chuck (max. 20 mm dia.) though. If any of you have any ideas for mounting a larger capacity chuck I'd love to hear them. I could make up a face plate for a 3" chuck that would screw on in place of the collet nut, but there must be other ways too. It would be nice to keep it as compact as possible.

I'm hoping to make some more progress today, so hopefully I'll have some more photos to show by Tuesday

Regards,

Jason

[BuckingFastards]

Great looking lathe, small, simple yet effective. Looking forward to see it completed.

[chenry]

what kind of spindle speed will you be aiming for?

convertible to 5C ?

[Jason3]

Originally Posted by BuckingFastards Great looking lathe, small, simple yet effective. Looking forward to see it completed.

Thank you! I'm hoping we won't have to wait too long

Originally Posted by chenry what kind of spindle speed will you be aiming for? convertible to 5C ?

Max spindle speed will be either 4500 rpm (0.5 Kw) or 5000 rpm (1.8 Kw) depending which servo I use to drive it. The headstock is rated to 6000 rpm, so plenty of headroom there.

I could make a new spindle to go to 5C. Although the front bearings look big enough to allow the back of a 5C collet through, it wouldn't leave much material for the spindle shaft where the bearings are. A back plate to mount a 5C collet chuck would also be doable, but there wouldn't be much lathe bed left south of the end of the chuck Also, the chuck would be pretty close to the bed...

I did look at using a Dunham headstock with a 5C spindle nose but that would have blown my budget of $0.00 I might have to be content with using a small standard 3 jaw for stock over 20 mm.

Righto, I am off to work on the cross slide...

Regards,

Jason

[hesham morsy]

chuck and Face plate
http://www.clisbyminiaturemachines.com/Accessories.html
http://www.lathes.co.uk/clisby/

[Jason3]

Originally Posted by hesham morsy chuck and Face plate http://www.clisbyminiaturemachines.com/Accessories.html :-)

Thank you for that, it might do nicely! I had a look at Little Machine Shop when I saw your link was out of stock - they also have a similar chuck, which is also out of stock...

However, I noticed LMC also have the dimensions for the 3" chuck - at 50 mm thick it might be ok on a faceplate. I'll have a measure up. It would reduce the available travel, but might still leave enough to be useful.

Best regards,

Jason

Edit - that's a real nice looking little manual lathe on that site. Hmmm...

[Jason3]

Not as much as I'd hoped though!

I spent some time considering the possibility of live tooling. Does anybody know whether Mach3 can handle live tooling on a lathe? I have a servo drive spindle planned, so indexing is no problem. I have no experience programming for live tool lathes either, so any advice would be much appreciated.

I made a start on the cross slide assembly today. The single wide rail is rebated to a light press fit into a slot on the top of the saddle plate, while the linear bearing block below will likewise be rebated to a press fit, to prevent any movement. This will also prevent any adjustment, however adjustment shouldn't be necessary as long as I machine it accurately. That's the plan, anyway!

Regards,

Jason

[ataxy]

wow cross slide is almost as big as the lathe itself! nice small built, will be plenty stiff for such a small machine.

[Jason3]

Originally Posted by ataxy wow cross slide is almost as big as the lathe itself! nice small built, will be plenty stiff for such a small machine.

True, the cross slide is quite big - it uses the same bearing and rail as the X. I think it will work well.

A little more progress, the saddle plate is pretty much done. It doesn't look much different, but sits a little lower now. It still looks very solid.

This little lathe sure is getting heavy fast

Regards,

Jason