I'm trying to build a cnc machine and I need to have quite a few parts turned. ballscrews, bearing blocks, etc, etc, I think the $$ would be better spent on a lathe that way i can try and build the parts myself and learn something.

Is there a small lathe in the ~$500 price that would be able to turn the ends of 30+" ballscrews? I guess i would need a lathe where I would be able to feed the material through the chuck, not sure what that particular feature is called. In my research on the web I haven't really seen this shown or described.. although this is all new to me.

Is there a small lathe in the ~$500 price that would be able to turn the ends of 30+" ballscrews?

No. You may get very lucky and find a deal on a used lathe, but even then, you would have to be national lottery winner lucky for what you need.

A 7x12 or 7x10 minilathe like this one
http://www.grizzly.com/products/G8688
have a spindle bore(.750 in) that will allow a .625 ballscrew to pass thru.
I turned my ballscrew ends before I tore my 7x10 from harbor Freight (http://www.harborfreight.com/cpi/ctaf/Displayitem.taf?itemnumber=93212) apart for another project.
A length of 30" or more could work if you support the other end from flopping in the breeze.
A block of wood mounted to the bench with a 5/8 hole for the screw to pass would be good enough to keep it level with the lathe.
It will be good enough to get the job done.
Hoss

No. You may get very lucky and find a deal on a used lathe, but even then, you would have to be national lottery winner lucky for what you need.

So, in your estimation is what i should look to spend? Do I need a really heavy duty unit for this type of work?

A 7x12 or 7x10 minilathe like this one
http://www.grizzly.com/products/G8688
have a spindle bore(.750 in) that will allow a .625 ballscrew to pass thru.
I turned my ballscrew ends before I tore my 7x10 from harbor Freight (http://www.harborfreight.com/cpi/ctaf/Displayitem.taf?itemnumber=93212) apart for another project.
A length of 30" or more could work if you support the other end from flopping in the breeze.
A block of wood mounted to the bench with a 5/8 hole for the screw to pass would be good enough to keep it level with the lathe.
It will be good enough to get the job done.
Hoss


Thanks for the info, im reading through the manual now.

what diameter ballscrews are u turning?

what diameter ballscrews are u turning?

the screw i have is 25mm in diameter. I have a couple of others ranging from 1/2-3/4 inch.

My advice is to get enrolled in your local community college and learn a lot about the various things that you are trying to do.
At the present you don't want to make "Ball Lead Screws" you will end up spending a lot of money on material due to mistakes.
best of luck to you.

John

I have done similar sized pieces (although not ballscrews) on my HF 8X12 lathe (actually an 8x14, HF just doesn't know how to measure a lathe.) It can be had on sale for around $440, and in my opinion is a much more capable machine than the 7x series. (A review can be read here (http://www.annisquamgranite.com/8x12ReviewPg1.htm).) You will absolutely need to support the end sticking out the head stock. (I actually have a place to bolt the steady rest to behind the lathe that puts it at the right height, but the wood blocks should work as previously mentioned.)

Nobody had asked this,
Are the ballscrews hard? if so you might as well do it with an angle grinder, if they are just rolled you might get lucky but either way its not easy to do regardless of the machine.

Chris

Take a look here; it may help you decide or at least it will be a very good recourse when you come to do it your self.

http://www.5bears.com/cnc16.htm

John

Nobody had asked this,
Are the ballscrews hard? if so you might as well do it with an angle grinder, if they are just rolled you might get lucky but either way its not easy to do regardless of the machine.

Chris

They are indeed hardened.

Take a look here; it may help you decide or at least it will be a very good recourse when you come to do it your self.

http://www.5bears.com/cnc16.htm

John

You pointed out this site in one of my other threads about lathes, and I learned quite a bit from it (actually lots of good info on that site, could spend a couple hours there), so I think I now have an idea of what the job entails. Is this your personal site? It was from this site that I got the idea that I might be able to turn these myself at some point when I learn what Im doing.

I don't think you would get good precision with an angle grinder. :) Turning hardened steel isn't that bad. Just make sure you have the proper tooling and take very light cuts. The only problem is since you will need to work slow and methodical it is easy to screw something up.

Hi,

Take a look at one of the ball screw manufacturers web sites. (THK for eg) they might offer advice.

I remember reading that they recommended setting the feed the same as the pitch of the ball screw you are machining, take a heavy cut to get under the case hardening for roughing out the shape.
I think the reason for this is if the pitch is not set the same, as you go across the crest / valley of the ball screw, the tool will have intermittant cutting. When the cut tries to restart, the tool will bounce off.

I havent cut ball screws, but sounds logical.
Or similar to another suggestion, use a proper tool post grinder. Googled this . . .http://www.dumorecorp.com/grinder.htm#tpg

Regards

Derek

My advice is to get enrolled in your local community college and learn a lot about the various things that you are trying to do.
At the present you don't want to make "Ball Lead Screws" you will end up spending a lot of money on material due to mistakes.
best of luck to you.

John

I agree. At this point I'd lke to buy a machine that has the capability to turn screws. Initially of course, I will be learning and experimenting on 'lesser' materials until I figure out what I'm doing.

You pointed out this site in one of my other threads about lathes, and I learned quite a bit from it (actually lots of good info on that site, could spend a couple hours there), so I think I now have an idea of what the job entails. Is this your personal site? It was from this site that I got the idea that I might be able to turn these myself at some point when I learn what Im doing.

Sorry for posting to you again; I forget who asks what.

The site is not mine I wish it was; it just always comes to mind when someone asks about machining ballscrews. I have used the information myself to very good effect. I don’t see any point posting lots of information when things are set out so well on a website or I know of a thread that has covered the subject already.

John

Sorry for posting to you again; I forget who asks what.

The site is not mine I wish it was; it just always comes to mind when someone asks about machining ballscrews. I have used the information myself to very good effect. I don’t see any point posting lots of information when things are set out so well on a website or I know of a thread that has covered the subject already.

John

Hi John, no complaints from me for the double post. that's a good site! thanks

The ballscrews are case hardened.
At least the Nooks from Homeshopcnc.com (http://www.homeshopcnc.com/page3.html)
and the Thompsons from Roton (http://www.roton.com/Mating_Components.aspx?family=7059321) that I've made for customers.
A tool with a carbide insert cuts through the case hardening no problem.
If you have extra screw stock, practice on some short pieces to get it down.
Then cutting your long screws will be no big deal. Leave a little extra just in case and cut it off later if it goes well the first time.
If you're new to turning, practice on something cheaper like aluminum.
Once you get 5/8 ballscrew turned down to about .500, it's pretty soft in there.
The 8x12 and 7x10 lathes have the same spindle bore of .750 but the chuck of the 7x10 has 5/8 thru, still works for the above screws.
Good luck, Hoss

The information on the HF 8X14 is very interesting. I was surprized to note that Grizzy does not have an equivalent although there is , in other areas, a lot of overlap. They do offer a 10 X 22 - http://www.grizzly.com/products/G0602 -
that has more than a passing resemblance to the 8 X 14 - anyone have any experience with it?

thanks

EM

For the case hardened screws it's so easy.
I will assume you have a bench grinder. Take the screw end to the grinder and grind it down until just about all the grooves are gone on the area you need to machine. Don't matter how ugly it looks just do it, you'll make it purdy looking on the lathe. This should take at the most 5 minutes.
Now chuck it in the lathe. Either a very good collet chuck or a 4 jaw. Mount a dial indicator and dial it in on the nice unground grooves. I just move the carriage to keep the indicator on the screws major diameter as I dial it in.
It'll even cut with a HSS bit since you ground off the hard outer layer.
Very fast and easy method.
Steve

$299.99 plus shipping
out of stock right now (no wonder at that price)
but they expect a new shipment to arrive on or about 9/1/2007

http://www.homier.com/detail.asp?SessionKey=QYx2ZFf8tiQ1L6TOVElUQlWrNhO59v3cYJg20zE1Ygt5wxwr4ziirepLYvwTm16bdONKRAzdyB3e&dpt=9&cat=225&sku=03911

The information on the HF 8X14 is very interesting. I was surprized to note that Grizzy does not have an equivalent although there is , in other areas, a lot of overlap. They do offer a 10 X 22 - http://www.grizzly.com/products/G0602 -
that has more than a passing resemblance to the 8 X 14 - anyone have any experience with it?

I looked at it before settling on the HF 8x14. Looks like a nice lathe, except it won't turn left-hand threads. (Probably not an issue for most people, but something I need it to do.) You might also check out Lathe Master (http://www.lathemaster.com) as they sell the 8X14 (and a 9X30).

Hadn't noticed the lack of left hand threads - not an issue for me - I did, however, find the standard threaded spindle very attractive as I find that I change chucks and collets frequently.

EM

I can send you SKFs brochure for ballscrew turning its in schwedish but there are good pictures

I looked at it before settling on the HF 8x14. Looks like a nice lathe, except it won't turn left-hand threads. (Probably not an issue for most people, but something I need it to do.) You might also check out Lathe Master (http://www.lathemaster.com) as they sell the 8X14 (and a 9X30).

I think I may be going with the HF8x12 myself. I may try and wait for a HF sale, keeping an eye on the webpage.

I've heard great things about the service from Bob at lathemaster, but I'm having a hard time justifying almost double for the Lathemaster even if it does have more accessories. I guess I need to price out the added accessories and go from there.

check out this website: http://www.fignoggle.com/machines/8x12lathe/index.htm

check out this website: http://www.fignoggle.com/machines/8x12lathe/index.htm

thanks, looks like the lathemaster is $918 shipped

The HF is 549.99 + plus these costs for items included in the LM price:

3 5" 4-Jaw Chuck* $58.50
4 Faceplate* $12.42
5 Follow Rest* $16.57
6 Steady Rest* $17.63
7 Splash Guard $17.37

=672.48
+39.99 shipping
+33.624 5% mass tax
= 746.09 grand total

The choice becomes more difficult.