Re: Turning hard materials
Easiest way is just to anneal the end of the screw. Heat up the end and wrap a damp cloth round slightly further back to stop most of the heat conducting down the screw.
If you're careful you'll end up with maybe 10-20mm of the portion you're not machining no longer hard ... but if your ballnut doesn't go that far then it's nothing to worry about.
Re: Turning hard materials
as Jonathan says annealing is not that hard to do. if the screw is not too long, you can put the screw in a bucket of water with the part you want to anneal sticking out of the water. also remember that after annealing you will most likely need to straighten the screw and you will be best to use a collet rather than a chuck.
Re: Turning hard materials
Re: Turning hard materials
So, all you need is a convenient induction heating unit! I was a little surprised at the straightening that was done. Assuming that any distortion would occur in the annealed section or at the boundary between that and the "left hard" section, wouldn't any slight loss of straightness be taken care of in the machining? If you are using the untouched threads to hold the screw (decent collet, etc) then I would have centre-drilled, brought up my tailstock centre, and just turned to dimension, confident that the turned part was going to be concentric with the body of the screw. What have I missed?
- Brian
Re: Turning hard materials
Quote:
Originally Posted by
Neale
So, all you need is a convenient induction heating unit!
I've been resisting the temptation to buy one of these for a while:
http://www.ebay.co.uk/itm/1000W-ZVS-...4AAOSwcu5URhOk
Perhaps I should stop resisting....
Re: Turning hard materials
Quote:
Originally Posted by
Jonathan
I gather that you've used the annealing method yourself - how did you heat the ballscrew, and do you think that there was any distortion? Was it machined out if so? I now have a lathe with a big enough spindle clearance for ballscrew machining, and trying to make sense out of the various sources of "advice" available via Google...
Re: Turning hard materials
Quote:
Originally Posted by
Neale
I gather that you've used the annealing method yourself - how did you heat the ballscrew, and do you think that there was any distortion? Was it machined out if so? I now have a lathe with a big enough spindle clearance for ballscrew machining, and trying to make sense out of the various sources of "advice" available via Google...
There are some pictures of one I did here - got a bit carried away with the heating, but I didn't notice any distortion - neither did I check carefully if I'm honest.
http://www.mycncuk.com/threads/4497-...0297#post30297
I used my Mum's cooker to heat it - it's a gas hob. Better off using something with a bit more power output though.
Re: Turning hard materials
Quote:
Originally Posted by
Jonathan
Not sure if that would do it from what I have been reading you need about 10Kw. Funnily enough I have been reading this today https://github.com/joshcam/ReactorFo...ctorForge-Core but decided a good Mapi gas blow lamp would achieve the same result cheaper
Re: Turning hard materials
I have a propane torch with range of burners from tiny to teenage dragon flame sizes. One should match "Mum's gas hob" plus a bit!
Thanks - always good to hear from someone who's actually done the job.