If i were to buy lead or ball screws without the ends machined for the bearings, so only the ballscrew and nut at a given length (maybe I will cut to length myself).
Is it hard to turn (on a manual taig lathe) the ends of the ball screw to the correct diameter to fit inside the ID of the bearings?
Has anyone done it? I havent tried it yet, still in the thinking stage. How will one clamp the leadscrew onto the lathe chuck? I mean, how to center it properly, as well as not damage the leadscrew while you are clamping it down to turn it. Presumably you should be clamping close to the lathe spindle, so thats where teeth marks will be from the chuck if any.
Anyone tried this before? Doable?
The last purchase I made for B.S.s were HiWin from Taiwan, I got a machinist friend to turn them as I did not trust my machining skills, he told me they were hardened all the way through and he ended up using ceramic tooling to machine them.
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Hmm somehow I dont really trust my machining skills either. I certainly dont have ceramic tool bits to machine with, only carbides.
I guess after softening the metal to turn it, presumably I will want to reheat treat them to harden them again, which if not done properly may warp the piece from residual stress?
Thanks for interesting feedback. certainly things to consider.
WHat about the poor man's way out? What if I dont try to turn the leadscrews at all. Instead I machine a sort of 'nut' that I screw in on the ends. Then it is this nut that is machined and it is this nut whereby there is a smaller diameter section for fitting the bearings for rotation? Essentially just adding ends to the ballscrew. Hell, I might even just weld or solder the part on? Will this poor man's way out work?
Is it hard to center the screw in the 4 jaw? Is it accurate enough to use ridges of the ball screw to center on, or do you need put an indicator on the ball valleys?
I have only machined one ballscrew in my life, but I will do it again if I have to! It was a 16mm from Isel, and I did both ends. I did not anneal it, but I used a large TOS lathe at work to rough it down to .5mm from final.
In my Emco v10 at home I more or less followed Kurt Bjorns recipe.
I made a support for the other end of the tailstock. I used the ordinary 3jaw chuck, and by alternately tightening and tapping the jaws with a soft mallet, I managed to center the screw to the point that the 0.01mm indicator did not move anymore. This of course only works if chuck and jaws are in good condition. The Isel screw was not hardened through, and the chinese ebay screws are definately not.
Don't think about welding if you are afraid of residual stress:-)
And there is no point in hardening the ends after machining.
Adding ends is doable. I would make it a tight fit and use epoxy to fasten it.
The 3M DP460 and DP490 are my favourite structural glues.
The free end of the screw might not need anything if you can find a bearing that slides onto the outer dia of the screw.
After contemplating whether to trust the local guy, who kept giving me the runaround, I ended up having a couple professionally done by a machine shop which specializes in ballscrew machining and repair. The drive and bearing journals came out perfect. It ended up costing more than what I paid for the ballscrews, but at least I know it was done right.
I would like to set up my lathe, so I can turn ACME screws. it's a very old lathe and the compound has some serious backlash. Another CNC project maybe...
I've "turned" the ends of acme screws with a drill, angle grinder and a file.
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I turned the ends of my screws for both my CNC gear head mill conversion and my 4x8 cnc router mill. These were ball screws from Mcmaster car. 5x8 size I think.
Turned the bearing seats as well as threadded the ends for for nuts on the ends.
That said, I hate using the lath, my lathe isnt that good and they didn't come out that true But I have run these machines since 2006 and have never had to adjust or do anything special to keep them working well. So can be done. but don't think you need to go through any heating process for al types of screws. Just regular lath tools were used to do what I needed to do to mine.
The OP said he has a Taig lathe. I don't think that will cut a ballscrew. The material is too hard and the spindle through hole is tiny.