Hi guys, I've decided that I need to be able to do lathe ops occasionally, but I can't really justify the space or expense of buying and CNC converting a lathe.

I have therefore decided to mount a lathe headstock and motor on my mill's table, and mount lathe tools on the side of my mill's head - I think this should give me basic turning and boring functionality under CNC.

So far, I have: Mini-Lathe headstock (from LittleMachineShop.com)
Mini-Lathe compound slide & tool post
Servo motor and Gecko on its way.

I am thinking that I am going to need a mini-lathe tail-stock as well, and a 'starter' set of cutting tools - is there anything else that I need to get started?

Cheers.

Hi guys, I've decided that I need to be able to do lathe ops occasionally, but I can't really justify the space or expense of buying and CNC converting a lathe.

I have therefore decided to mount a lathe headstock and motor on my mill's table, and mount lathe tools on the side of my mill's head - I think this should give me basic turning and boring functionality under CNC.

So far, I have: Mini-Lathe headstock (from LittleMachineShop.com)
Mini-Lathe compound slide & tool post
Servo motor and Gecko on its way.

I am thinking that I am going to need a mini-lathe tail-stock as well, and a 'starter' set of cutting tools - is there anything else that I need to get started?

Cheers.

I don't know how big your mill is but you might want to look at sherline or taig. Also don't forget you mill can do lathe ops to a certain extent also.

chris

If I buy a standalone lathe, however small, I will still have to go through the extra expense of adding steppers/servos and motor mounts etc to it to get CNC. If I use my mill for X and Y/Z then the CNC part is free.

I also already have 1/3 of a lathe sitting on my desk...

A lathe, as well as a mill, do not need to be CNC to be useful. With your current plan you will lose the very useful function of being able to cut threads.

Reqards
Phil

If I buy a standalone lathe, however small, I will still have to go through the extra expense of adding steppers/servos and motor mounts etc to it to get CNC. If I use my mill for X and Y/Z then the CNC part is free.

I also already have 1/3 of a lathe sitting on my desk...

A lathe, as well as a mill, do not need to be CNC to be useful. With your current plan you will lose the very useful function of being able to cut threads.

Reqards
Phil

Believe me, I need my tools to be CNC'ed :)

I was hoping that screw cutting might be possible as the spindle motor is a servo, and so has a precicesly known RPM. If I can coordinate the X with the spindle, won't I be able to cut screw threads?

I don't know much about it but I do believe it is not as simple as you may first think.

Regards
Phil

Believe me, I need my tools to be CNC'ed :)

I was hoping that screw cutting might be possible as the spindle motor is a servo, and so has a precicesly known RPM. If I can coordinate the X with the spindle, won't I be able to cut screw threads?

Believe me, I need my tools to be CNC'ed :)

I was hoping that screw cutting might be possible as the spindle motor is a servo, and so has a precicesly known RPM. If I can coordinate the X with the spindle, won't I be able to cut screw threads?


You would think it should be this easy wouldn't you.
In the world of VMCs we spend MANY thousands of dollars for special driver boards that allow us to rigid tap.
I think the biggest issue with tapping is keeping the sync during decel and acel when reversing.
If you run constant speed/feed with a tach on the lathe RPM you may be able to thread acceptably.

I would think the threading less problematic then tapping for just the reason you mention DareBee, reversing.


The math is simple enough for this, (Precise) RPM X thread Pitch = Feed Rate.
It should be doable.


Some controllers I believe round up fractional feed rates, this may be a problem.

Example
1/4x28
Pitch = .035714
RPM = 1500
Feed = 53.571

In practice I'm not sure how much difference a increase of .429 in the feed rate would make.

Some of you math whizzes figure it up in distance. I have not had my full pot of coffee yet :D

Don't forget you can thread mill as well. Mach 3 does do thread milling, but whether you can get it to properly treat your lathe spindle as a C axis remains an open question from what I"ve seen. It does not do rigid tapping, for example. Also, Mach lathe support has lagged mill support considerably, especially for the newer devices such as GRex. Art has promised to invest a bit of time near term improving Mach 3 Turn. You might want to pop over to that board and inquire about how to do what you want to do.

There once was a video of a mill being used as a lathe to make bushings. I've lost track of it, but it was a clever idea. This fellow used the mill's spindle as a lathe spindle, and the table as a lathe gang tooling plate. He had mounted toolholders all around the center, so he could approach the workpiece from a couple of directions to make the parts.

I was reading an old thread the other night and saw this intriguing setup by CNCZone contributor Geof:

http://www.thewarfields.com/cnccookbook/img/OthersProjects/Geof4Axis.jpg

He needed to face those 8 aluminum bars to length and drill and tap each end. He says this setup on a 4-axis mill will do the job faster than a CNC lathe. That got my attention. I thought about it, and the answer has to be because he had to drill and tap both ends of the rods. In a lathe that would require manually swapping the rod end for end (unless you have a fancy multi-spindle machine!) and in this setup it all gets done auto-magically.

That video of a mill making lathe bushings and Geof's idea for machining bars really opened my eyes to what some creative out of the box thinking can do.

Just so you don't think I'm a total mill bigot and hate lathes, I read another fellow who had improved productivity by using his lathe with bar feeder to act as a precision cutoff machine. He was just facing and chopping bar to length in order to make blocks to feed his mill. Said it worked out very well for him.

Best,

BW

Digits,
I have a 9x lathe and cnc'd x3 mill but also have a spare 7x headstock and tailstock I have been trying to figure out what to do with. Thought about using it as a second higher speed spindle for my x3, maybe a horizontal spindle or even as a lathe on the mill like you are talking about.
Keep us updated with your project!
Steve

Cheers guys - I haven't had much time to work on this yet - been madly building my new enclosure before I am inundated with 100's of lbs of extrusions, ballscrews and aluminium plate for my new mill+lathe project.

I suspect the lathe will be one of the last bits I get going, but I need to order a tail stock and some basic lathe tools tomorrow so that I'll have all the bits when the time comes.

I hadn't really thought hard enough about the software side of it - I was thinking that for boring and facing, I could just write some snippets of G-code , but I haven't really looked at how Mach 3 deals with spindle speed control.

The link below shows a nice setup (mill/lathe) for wood/foam.

What will you be cutting?


http://www.cnczone.com/gallery/showphoto.php/photo/857/cat/500/ppuser/1498




.

The link below shows a nice setup (mill/lathe) for wood/foam.

What will you be cutting?


http://www.cnczone.com/gallery/showphoto.php/photo/857/cat/500/ppuser/1498




.

I plan to be cutting lots of aluminium (mostly 6082 but some 2014 and C250 plate)

Isn't that link a 4-axis setup rather than an acutal lathe?

I plan to be cutting lots of aluminium (mostly 6082 but some 2014 and C250 plate)

Isn't that link a 4-axis setup rather than an acutal lathe?

Yes (4-axis).

Another photo shows the table, a little better:
http://www.cnczone.com/gallery/showphoto.php/photo/418/cat/500/ppuser/1498

The router tilts 90.0 deg. to switch from mill to lathe op.



.

Yes (4-axis).

Another photo shows the table, a little better:
http://www.cnczone.com/gallery/showphoto.php/photo/418/cat/500/ppuser/1498

The router tilts 90.0 deg. to switch from mill to lathe op.



.

That is a very nice machine :)

I have a 4-th axis already - I'm just fine tuning it now, and I hope to use it in anger soon :) However, I still think that some jobs will be better with a stationary tool and a moving work-piece which is why I want a 'real' lathe attachment on my mill.

Cheers.

Actually, I suggested to a friend to mount his mini lathe to the bed of his CNC Bridgeport mill. All that was required was to unbolt the ball nuts of the “X” & “Z” axis of the lathe, bolt on a simple “socket’ to the top of the tool post, and chuck a piece of ground & polished bar stock in the mills spindle (everything was easily converted back to stock afterwards). With a free moving toolpost, the mill was programmed to just “push/pull” the toolpost were needed. It actually worked pretty well! My friend sold the mill a couple of years ago, but still misses the mill/lathe combo.

Actually, I suggested to a friend to mount his mini lathe to the bed of his CNC Bridgeport mill. All that was required was to unbolt the ball nuts of the “X” & “Z” axis of the lathe, bolt on a simple “socket’ to the top of the tool post, and chuck a piece of ground & polished bar stock in the mills spindle (everything was easily converted back to stock afterwards). With a free moving toolpost, the mill was programmed to just “push/pull” the toolpost were needed. It actually worked pretty well! My friend sold the mill a couple of years ago, but still misses the mill/lathe combo.

That is an interesting idea! But I don't have enough spare linear slides to have more than an X-axis on the table-top.

I have just ordered a tail stock, but I didn't order any other tooling as my favourtie mail-order supplier is out of most interesting stuff. I seem to have a 4-way tool post on my mini-lathe compound-slide - is the thing supposed to be turnable?

digits,
Did you ever finish this project? I decided today to put my 7x headstock to good use on my cnc'd x3 mill. I modified the headstock so the motor is direct drive with a toothed belt. I made a spindle clamp for the mill so I can mount tooling in the spindle using collets. Or I may just mount my lathe QCTP to a collet mounted stud with a modified collet so it tightens flush against the spindle face( ala tormach style)
I just have to mount the headstock to the table. Aligning it is no biggy for me as I have a decent procedure I use.
I figure this setup will be good for simple smallish parts and the parts can also be quickly crossdrilled or milled in one setup if I add a clamp to the lathe headstock.
Steve

.

Or you could use the mill spindle and gang tooling.
http://www.youtube.com/watch?v=wbfXXeiSHsw
I have made thousands of these bronze bushings
on a taig mill
Mark

Or you could use the mill spindle and gang tooling.
http://www.youtube.com/watch?v=wbfXXeiSHsw
I have made thousands of these bronze bushings
on a taig mill
Mark

How would I attach the workpiece to my mill's spindle? I really want to do exactly the same to "turn" four aluminum spacers for my X and Y motor mount. Right now, they are plastic.

http://farm1.static.flickr.com/209/475947347_b1cc87548d_m.jpg

hoss2006,
excellent work and very nice website! It seems I pretty much setup my headstock motor drive like you did except I am using the stock iron housing. Now I am really pumped to get this setup up and running after seeing your videos. I have a cnc'd rotary table and now with the lathe head this is going to be a very versatile machine.

metalbyter,
I had seen your video before. Very impressive! It really shows how versatile a cnc'd mill can be with a little imagination on setup.

Well I have to get back to work on the mill/lathe setup.. I'll post some pics when finished.

Steve

How would I attach the workpiece to my mill's spindle? I really want to do exactly the same to "turn" four aluminum spacers for my X and Y motor mount. Right now, they are plastic.

http://farm1.static.flickr.com/209/475947347_b1cc87548d_m.jpg

I'm holding my parts in a collet chuck.
Mark

I've said it before, but Hoss, I really like your setup!

My mill/lathe construction project is still on going (my X-1 is busy making parts as I type!) - not started the lathe bits yet though, but I plan to have my tool post on the mill head assembly.

Thanks metalbyter. I was curious if you used any special attachment for that.

I was looking at a recent KBC Tools catalogue and they have a small chuck mounted on a backplate that screws into a 5C collet fixture.

It is 3" diameter OD with a capacity of 5/64" to 2-15/32" with a 5/8" through hole and a weight of 5 lbs.

This could probably be adapted onto a different taper and might work quite well for turning on a mill. The part number is 1-850-Z9550 and you should be able to find it at www.KBCTools.com

Thanks for those information Geof, they are a little pricey for me, I thought it would be for some reason before hand. :-)

So, I probably get a micro lathe from HF, just to see what it is all about (turning, facing, etc).

Finished up the setup. Seems to work real nice after some quickie tests.
This is just for fun but it should be able to make some nice smallish parts.
I'll add a spindle sensor so maybe it could do some threading.

Setup details, 7x head with a dual 3m poly belt drive I made on my 9x lathe.
Head is bolted through the table and uses a rear clamp also.
A spindle clamp locks the spindle from rotating. A 3/8" R8 collet is ground so it allows the 4 way tool post to sit flush against the spindle face.
The quill allows fast tool centering.
Turning uses the table x and Y axis for feed which on my mill is pretty good with .0005" or under backlash.
I have a 7x tail stock also if needed.
Now I just need to learn how to program it,lol.
http://i109.photobucket.com/albums/n48/S_J_H/x3%20mill/milllathe011.jpg
http://i109.photobucket.com/albums/n48/S_J_H/x3%20mill/milllathe009.jpg
http://i109.photobucket.com/albums/n48/S_J_H/x3%20mill/milllathe007.jpg
http://i109.photobucket.com/albums/n48/S_J_H/x3%20mill/milllathe006.jpg

Steve

oh, i gotta have one of thoes!!! i was thinking about converting my mini lathe over to cnc and running it as a seperate system from my mill... but this just might be the way to go...

so are you running turn with this setup or mill, and some imaginative programming? i dont need to thread anything, i just need to be able to make my parts over and over again...

so are you running turn with this setup or mill, and some imaginative programming?

Well this cnc lathe on a mill stuff is all new to me. I have been using mach3 mill for a couple of years but never used Mach Turn. I have some learning to do before I can put this thing to good use. But right now the mechanicals of the setup seem to be working pretty well.

Steve

Hey project5k,
I played around with the wizards in Mach 3 Turn and they were pretty easy to use.
Here's a few sample videos trying it out on mine.
http://www.hossmachine.com/projects_5.html
towards the bottom of the page.
Also here.
http://www.youtube.com/hossmachine
Also try Bob Adams Cad2lathe (http://members.tripod.com/STcnc/id22.html).
Hey S J H, could you explain the spindle sensor for threading?
I am adding a spare stepper to be able to do 4th axis stuff and threading but would like to hear if the dc motor could do it instead.
Thanks Hoss

Hoss,
the way I understand it is that MACH can read the spindle speed by using a senor on the spindle and then adjust the feed to match for threading.
The lathe guys would be a much greater help than me. Ron111 posted a lot of info and a how-to in his thread- http://www.cnczone.com/forums/showthread.php?t=32470&page=4

Post#41.

Steve

so help me understand the tool holder that you are useing for this.. it looks like maby its locked up into the spindle with an external clamp or something of the sort.. i would think that the tool holder in the spindle would just cause the spindle to turn under cutting loads.... how is it held steady?

also, on all these x3 machines, when you convert to cnc, your moving the whole head up and down, not just using the quill right? the quill is parked up inside the head, and locked into place somehow? I'm asking these silly questions as i dont have my machine yet, so i've never actually seen one of these in person up close...

project5k,
The quill always has a lock so if your machine has a quill you lock it if you are using the head movement as the z-axis. Some guys lock the head and motorize the quill. I think that is done more often by the round column mill guys though.
In my picture the square clamp locks the spindle to the stationary quill. With the clamp installed the spindle can not rotate at all. The tool holder uses a stud inserted into a r8 collet which had the face ground down to allow the holder to seat flush against the locked spindle face. I lock the stud into the collet and then just slip on the tool holder and tighten it to the spindle face with a nut.
It all works great.

Steve

ahhh ok, that makes sence, i was laying in bed last night thinking about how to do that, and i ended up with the tool holder in a collett locked up in the spindle as well... I'm sure that my x3 will have the lock, but i cant say with any athority till it gets here (TOMARROW!!!!) YIPPIE...

Going this route makes so much more sence than having 2 sepperate machines (a mill and a lathe) for me now... perhaps later, when i need more production quantity i can look at doing the rough outline cuts on a cnc lathe, and then doing the 3d carving 4th axis with the mill...

Well I have no lathe cam software and don't know how to use G-code very well.
I messed with MACH Turn for a little while and it only gave me a headache.
Well heck, I don't know any better so I improvised to be able to just use my milling software and stay with Mach Mill. I just drew the tool path I wanted in a cad program. Real easy and fast to do using built in commands. Then I just used my milling software(sheetcam) to convert the cad toolpath into g-code and give it a feed rate. The DOC for turning is configured by the drawing itself. The drawings are just one long continuous line. The drawing can easily be scaled. I drew these 2 tool paths as a quick test of method and madness. They seemed to work pretty efficient as there is almost no wasted movements.
tool path drawings-
http://i109.photobucket.com/albums/n48/S_J_H/lathetestpart2007.jpg
http://i109.photobucket.com/albums/n48/S_J_H/lathetestpart2008.jpg
One of the drawings being converted to code by Sheetcam-
http://i109.photobucket.com/albums/n48/S_J_H/lathetestpart2010.jpg
The resulting test Gazinta from lathe head sitting on a cnc mill.
http://i109.photobucket.com/albums/n48/S_J_H/lathetestpart2005.jpg

Steve:rainfro: