The "Parts Bin Micro Lathe"

[rowbare]

Very nice. What kind of the spindle/headstock are you using?

[Jason3]

Very nice. What kind of the spindle/headstock are you using?

The headstock is actually a 90º live tool for a big CNC lathe. It came free as parts with another straight one I bought. It's new, but the bevel gear drive had a flaw in one tooth and wouldn't turn smoothly. Other than that it seems perfect. I removed the drive shaft and gears, as you see it mounted the drive shaft used to come out the bottom. It's got a nice big set of angular contact bearings at the business end, and a decent size unknown type bearing at the back. I measured runout in the taper at 0.005 mm (0.0002"). Not bad, but to be honest I expected a little better. I haven't checked the bolts are torqued properly yet, and the back bearing isn't secured so the runout might improve once I attend to them.

I've roughed out the cross slide now, I made it from Fortal as I wanted it to be as strong and rigid as possible while sticking to aluminium parts (I'll get everything anodized once it's finished). I also wanted enough material to be able to bore the cross slide for a 20 or 25 mm dia. NSK spindle for live tooling. I cut a pocket in the base to lower it a little and keep plenty of material around the tool holders, particularly the threading and turning tools. It still has a lot of detail left to go into it, but I intend to use the lathe itself to bore for the collet chucks and live tool, so I will have to get it running before I can finish that part.

I'm not getting anywhere conclusive regarding using Mach3 to control the spindle as a rotary axis for live tool use. Any advice from someone who has built a live tool lathe would be gratefully received!

Best regards,

Jason

Ps - Hesham - no luck on the lathe chucks from the Clisby lathe. Sad news - they are closing down. A shame - the lathes look really neat.

[veteq]

Hey Jason,

nice machine you got over there, what are you going to use for motors.
Nema 17 servos will be nice i think, with a 2mm lead ballscrew these very nice units will give more then enough torque.

http://cgi.ebay.com/API-Servo-Motor-...3286.m20.l1116

Think the live tooling is positioned and activated in the cam software, from there out it gives a G or M ( in a good package configurable) code to mach. But maybe somebody else will know better.
for example
http://www.solidcam.com/turning_en,2686.html

Regards,

Roy B.

[Jason3]

Hi Roy,

Those servos are pretty similar to the ones I have actually - nice little units. The ones I'm intending to use are the Allen Bradley Y-1002-2-H00AA, similar to these: http://cgi.ebay.com/Allen-Bradley-se...2em118Q2el1247

I've got some Allen Bradley drives for them, but they are a bit bulky. Since the lathe will be very compact, I am thinking about using my new favorites, Granite Devices' VSD-E, to keep the whole setup as small as possible.

Thank you for the clues on the live tooling! That helps, it should get me started

Best regards,

Jason

[Jason3]

Started mounting cutting tool holders today I cut a slot for the first tool holder and relieved the front face of the cross slide to clear work up to 2" dia. Larger parts will still fit, but I won't be using this tool to turn them - I'll use a left hand boring bar on the front corner of the cross slide for those parts. If I do need to bore a larger part, I'll reverse the spindle and cut on the back side with the same bar. Maybe...

First photo is relieving the cross slide, bit of product placement there for Maritool... I'll be waiting for the freebies, Frank

Next, a photo from the 'back' side, showing a typical size for the parts I'll be wanting to make, so you can see how the weird setup will (hopefully...) work.

Comments are welcome, this is my first shot at a lathe so any pitfalls avoided I'll be most grateful for.

Best regards,

Jason

[SpeedsCustom]

Very awesome, like that idea a lot!

-Jason

[Jason3]

Very awesome, like that idea a lot!

-Jason

Thanks, Jason - I appreciate the comment!

Tooling space and clearance is going to be tight with this machine, especially as a gang tooled lathe. I've decided to extend the cross travel to 6", up from 4". Fortunately I left the saddle plate and linear rail long to trim later, so it won't mean changing much.

A supplier managed to find a small threading tool holder for me that has the shank parallel to the spindle axis, this will mean I can line it up with the drills and boring bar across the front of the 'toolpost' block.

It's getting heavier, looking like being 50 - 60 Lb now. Guess I won't be moving it around as much as I imagined. For a brief moment I envisaged taking it on holiday, sitting by the beach with my feet up, sipping a cool drink while the little lathe whirred away making parts by the dozen

Oh well...

[Jason3]

I've had a few days off (holiday weekend here) and have been installing a DRO on the manual mill, so no actual machine build progress.

But, some more tools arrived today - this should let me finish off the cross slide/tool post, hopefully in the next day or two once I get this DRO installed.

Here's a pic of the tool holders for the initial setup. The boring bar (left) is tiny at 1/4", so I got a carbide one to help reduce the possibility of chatter. It has through coolant capability - a nice touch that should really help flush chips out of the smaller bores.

The next tool holder has some very sharp polished inserts intended for cutting aluminum, but I happen to know they can also deliver an excellent result is stainless steel, though you do need to be careful to avoid heavy or interrupted cuts as they are quite fragile.

The last two are 3/4" x 2" shank ER16 collet tool holders I'll use for drills and the like. They're balanced to 30,000 rpm - nice to know, and completely unnecessary for this application I haven't decided whether to mill a flat on them for a set screw or use a clamp type mounting scheme yet.

Best regards,

Jason

[H.O]

Nice build!
A thought regarding the live tooling and indexing of the spindle. Mach3 has a macro command with which you can swap two axes. If you set up the servo driving the spindle is a S/D servo then perhaps it would be possible to swap the spindle axis with the C-axis when you want to do indexed operations and then swap back for ordinary turning. You would have to ref the C-axis everytime you switch from "standard spindle" to "indexed spindle" though but perhaps that's workable.

Never done it myself but it might be worth investigating.

/Henrik.

[Jason3]

Nice build!
A thought regarding the live tooling and indexing of the spindle. Mach3 has a macro command with which you can swap two axes. If you set up the servo driving the spindle is a S/D servo then perhaps it would be possible to swap the spindle axis with the C-axis when you want to do indexed operations and then swap back for ordinary turning. You would have to ref the C-axis everytime you switch from "standard spindle" to "indexed spindle" though but perhaps that's workable.

Never done it myself but it might be worth investigating.

/Henrik.

Now that is interesting! I will have a search and see if I can figure that macro out... I'm pretty certain that the servo I'm using for the spindle drive has an index pulse output from the encoder - if not I would need to add something for threading anyway, so perhaps that could be used to ref. the spindle home when switching.

Thank you!

Best regards,

Jason

[Jason3]

The first picture is of part of the reason for the slow progress - my DRO Y axis scale wasn't reading. I pulled it apart, but couldn't find anything amiss. Eventually, I put it back together thinking to give it one more try before I returned it. I plugged it in and it worked... Nice!

Anyway, with that sorted out I finally got a little time to make some more progress on the baby lathe - a mount to fit the Servo I'll be using for a spindle motor. It looks a bit unusual hanging out the back that far, but I think it'll be a bit less obvious once there's some more bulk up the business end.

Also, with the arrival of a special threading tool holder, I've gathered together the initial tooling I'll need to get this machine running. There's still a way to go, but it's getting closer!

Regards,

Jason

[jdr]

Jason,

Very nice looking motor mount for the C-axis.

I always enjoy reading your posts.

This lathe could be New Zealand's first homegrown Omniturn. Keep posting pictures of your progress.

I also have been looking at the new Minitech gang tooled lathe. Might want to Google for Minitech's pictures.

Jack