Lathemaster 9x30 Stripped Down for Conversion

[jorgepease]

I have received my lathe and spent a good part of the day cleaning it up.

I am going to be converting this lathe to CNC. That will include new ball screws on both axis, and a new VFD beefier motor.

A few pics attached. I plan on adding a coolant system and build a closet around this thing. It will not be used as a manual lathe, I decided I would get another if I need to.

Now I don't know much about this type of stuff but I was thinking about connecting straight from motor to spindle. Is that acceptable. Should I be using a cog'd belt or the Vbelt. Any suggestions on pulley ratios etc...

Are the existing motor mounts std. I keep reading that changing out the motor is supposed to be real easy. Should I plan on new motor mounts?

More questions to follow as I progress

Thanks

[Al_The_Man]

Maybe you should have kept it in one piece to make the parts for the conversion .
I am looking at doing a similar lathe to CNC, It depends on what the final spindle speed you need, if you go with the largest motor you can fit, (fortunatly 3ph motors are smaller that their 1 phase counterpart), I would fit a C face motor if possible and use a 4 pole motor at double the frequency i.e. 120hz.
and use a timing belt, if you want CSF and threading, you will need an encoder on the final spindle shaft.
Post the pic.s as you progress.
Al.

[jorgepease]

I wont have my space for a couple of months, want to have it ready when I am set up.

Not sure what my top spindle speed could be. The stock lathe (.75 hp) had a max rpm of 2000. I probably want to limit it to 3000. Any thoughts on this?

Just did a search for 3ph motors. I think the cheapest thing I saw was $700 (1 hp) and the VFD control is another $250. Maybe I will check Ebay, any other recomendations on this, thanks.

[Al_The_Man]

A source of 220v motors is to phone around the local Motor dealers and rewinders for used, much cheaper.
And ebay is usually a good source of quality VFD like Mitsubishi, Telemecanique, Weg, Square D etc.
A 4 pole motor at 120 hz will give you around 3,600 at the motor shaft, so you could gear down slightly.
Al.

[jorgepease]

Can you check this link and tell me if this Baldor motor would do

Never mind, tons of motors cheap!

[bill south]

Hey Jorge;
You may want to contact Bob Warfiled "www.thewarfields.com". He has the same lathe and I think has done some investigation into a conversion process. Regardless, I know he'll be interested in this thread. Have a good un!
Bill

[jorgepease]

Hey Jorge;
You may want to contact Bob Warfiled "www.thewarfields.com".

Bill,

I have visited his site and hope to discuss some ideas and issues with him.
Thanks!

I am trying to order my Ball Screw Assemblies from Nook and I have a couple of questions.

1. Since I am scrapping all Feed Gears, Handwheels basically everything that the screws drive or are driven by, then the Lead does not have to match the existing screw, Right or Wrong? Is the Lead one of the setups in the software? Is there a particular Lead that would be better for this little lathe?

2. Nook caries three Ball Screw Models. I am leaning toward the mid-range XPR Model which has Lead accuracy of +- .001 in/ft. A step down would be the SRT which has Lead accuracy of +- .004 in/ft. I don't know cost yet, they have an even more accurate screw but I think that might be overkill, some thoughts on this, thanks.

3. Pre-Loaded or not? From what I have read on these forums I think the answer is Pre-Loaded but would like to verify.

There is lots of space to work with on the Z axis but the cross slide is tight.
Any ideas on how to attach the new Ball Nut with a post like on the square nut. See the Pic.

Thanks for your suggestions.

[Al_The_Man]

If you are going direct drive, then you need the lowest lead possible, like .2" max ,You should use pre-loaded for CNC applications.
What is the width, incidentally of the Z axis slot on that lathemaster?
Al.

[jorgepease]

What is the width, incidentally of the Z axis slot on that lathemaster?
Al.

The slot for the slide screw is 1.1 wide by about 0.9 deep. The existing screw has a Root Dia. of about 4.4 and a lead of 0.2.

The only Ball Nut assembly small enough (from Nook) to fit in the slot has a Root Dia. of 0.3 and that one has a Lead of 1.25. The thread to attach the new Ball Nut is 0.664-32. I think that leaves enough clearance for a pretty stout bracket to attach the new ball nut. I don't think the new 0.125 smaller dia screw will be a problem for my light duty application.

Thanks for the info, I'm going preloaded and 0.200 and under on Lead. I am drawing out the new brackets and apron now.

[BobWarfield]

Hola amigos!

Jorge, I am sure that like Ron111, you will be another guy who starts his lathe conversion after me, and leaves me in the dust by finishing in no time flat!

Fortunately, I always learn a lot from you fellows!

As you've probably noticed, I'll be direct driving my lathe to start, though I am not starting out with ballscrews.

On the motor, check out my DC treadmill motor conversion. It works great and its cheap. Similar to what a lot of guys do on the smaller lathe. These machines just don't need the horsepower of an AC motor, and it's very cheap to be able to find a variable speed motor controller and treadmill motor on eBay.

The other possibility if you choose the DC motor is to put an encoder on it and make it a servo. This would let you index the spindle, attach live tooling (i.e. a drill) to the tool holder, and do some pretty cool things.

I think the secret on the ballscrews is going to be all about how you mount them. You'll need to track down an appropriate set of angular contact bearings as well as make a block to mount the bearings in. The cross slide is really tight for a ballscrew, consider attaching the ballnut out at the end rather than in the middle, so it is literally bolted to the end of the cross slide rather than being machined inside of it.

Jorge, you're doing so much nice work there, did you ever consider popping off the little compound, and attaching a couple of small linear slides atop the apron? You could make a whole new cross slide based on linear slides and a ballscrew. Would take a fair bit of ingenuity and mill work, but it would sure be cool!

Best,

BW

[Al_The_Man]

The other possibility if you choose the DC motor is to put an encoder on it and make it a servo. This would let you index the spindle, attach live tooling (i.e. a drill) to the tool holder, and do some pretty cool things.

On a CNC lathe the spindle encoder should always be mounted on the final spindle shaft, especially if you want to either simulate C axis indexing, Live tooling or even CSF or threading.
Al.

[jorgepease]

Hi Bob,

It was your posts that influenced me on buying the Lathemaster 9x30. Glad I did, this machine is really strong. I can definately see using this for small production runs. I am going to beef it up as much as possible.

This is my first time doing something like this so I am going to buy the ball screws and mounting blocks all together. Some of the mounting blocks have integrated motor mounts.

The compound is out of the picture. A heavy duty tool post will take its place.

Mounting the ball nut at the end of the slide might be the way to go. I will have to look into that. I drew it up in the computer and looks like there might be just enough room in the slot to leave it where it is.

I would love to power the spindle with a Servo. I hope I can make that part of the mod. Any info you can provide on this would be great. On the other hand maybe I can fashion an easy on/offmount for a direct drive stepper to the spindle shaft. When I want to use the spindle like a rotary table I engage the stepper, otherwise I engage the VFD.

Cheers

Jp