Problems working the end of some ball-screws

[mauribastidas]

I have some problems working the end of some ball-screws from Keling, they are really hard and the lathe doesn’t “clean” the thread of the screw, I think that it would be a good idea to heat them in order to “soften” the metal, is it a good idea? How can I solve this problem, thanks for your help.

[mactec54]

mauribastidas

Don't heat it up, if the heat travels up the screw,it will soften the screw were the ballnut runs & that would be bad

If you can't get it machined, set up a grinder to do it, or have it done in a machine shop that have a grinder

I show how to do this in a lathe, here in my machine build
http://www.cnczone.com/forums/cnc_wo..._friend-7.html

[tskguy]

‪screwballs pool scene .‬‏ - YouTube
Screwballs!!! thats funny

[Gumby]

Originally Posted by mauribastidas I have some problems working the end of some screwballs from Keling, they are really hard and the lathe doesn’t “clean” the thread of the screw, I think that it would be a good idea to heat them in order to “soften” the metal, is it a good idea? How can I solve this problem, thanks for your help.

Do you mean ball-screws? I don't think you should heat them up if this is what you are talking about. Depending on the particular grade of steel they are made out of that may actually make them harder when it cools.

[mauribastidas]

Thanks for your help mactec and gumby and sorry for the mistake, they are ball-screws. I suppose it is not polite to joke about this kind of errors, especially when English is not your first language.

[RomanLini]

You can use a bench grinder or even an angle grinder to take off the top hardened skin of the metal, it does not need to be pretty as you fix it up with the lathe afterwards.

[mactec54]

RomanLini

On most good ballscrews the hardening is deeper than the amount that you will be machining off the screw, So rough grinding does not help that much, But can help if you can grind it off even all the way around the area that you are going to machine, Carbide does not like machining a rough bumpy/uneven hard surface, & can end up worse to machine if not ground smooth & round

The ballscrews in my build that I showed being machined still had more than .060 of case hardening left when machining was finished

[mauribastidas]

Thanks for you interest in my problem, I supposed it was a good idea to heat the screw but you say that it is dangerous because it can affect the hardness of it. Is it a big variation considering I would heat only a short part of the screw?

[acondit]

Wrap a wet rag around the screw below the part you are going to aneal (soften). It will act as a heat sink and protect the rest of the screw.

Alan

[RomanLini]

Originally Posted by mactec54 RomanLini On most good ballscrews the hardening is deeper than the amount that you will be machining off the screw, So rough grinding does not help that much, But can help if you can grind it off even all the way around the area that you are going to machine, Carbide does not like machining a rough bumpy/uneven hard surface, & can end up worse to machine if not ground smooth & round The ballscrews in my build that I showed being machined still had more than .060 of case hardening left when machining was finished

Thanks for the info Mactec54, I've seen how good your machining work is so you won't get any arguments from me!

My limited experience was based on my 12mm ballscrews that only had thin surface hardening, so that ground off easily and then I lathed it down to 1/4" for the couplings.