Best way to machine ball screws?
Hi everyone,
I'm trying to set up my lathe for machining ball screws but I'm not sure of the best tooling to use. I've seen a couple of other posts that say to use carbide inserts but are there different types, shapes and qualities of carbide?
The sets of 5 indexable look to be a winner but are they overkill?
I also need a quick change tool post holder as well if anyone can recommend a good one, life's to short to spend it shimming cutting tools.:heehee:
Thanks in advance
Re: Best way to machine ball screws?
Ross
Try this guy on Ebay under number 290448499618. I bought one of these for my Southbend 13" and have to be honest been bloody pleased with it. You have to machine the plate to match your saddle slide. Check the details so that you get the right size on his pages.
Re: Best way to machine ball screws?
When I built my machine a couple of years ago I had to have the ballscrews machined.
The guy who did it is an experienced tool maker who is used to working with hard materials etc
But he had a right job machining the ballscrews because they were so hard :sad:
Andy
Re: Best way to machine ball screws?
In general a lot of these are only case hardened, use a grinder to take off the bulk and the the lathe to square everything up. just make sure cutters are very very sharp and expect to get them blunt. If you are using indexable tips then there are plenty around that are specific for hardened materials. Use plenty of coolant.
Re: Best way to machine ball screws?
Quote:
Try this guy on Ebay under number 290448499618. I bought one of these for my Southbend 13" and have to be honest been bloody pleased with it. You have to machine the plate to match your saddle slide. Check the details so that you get the right size on his pages.
Thanks that looks good, dose the dovetail holder tail pull in really tight? £100 seems to be about the price for them as well
Quote:
When I built my machine a couple of years ago I had to have the ballscrews machined.
The guy who did it is an experienced tool maker who is used to working with hard materials etc
But he had a right job machining the ballscrews because they were so hard :sad:
Yeah I'm not expecting it to be easy, just want to have a fighting chance by using the most suitable tools.
Quote:
In general a lot of these are only case hardened, use a grinder to take off the bulk and the the lathe to square everything up
That sounds perfectly feasable but isnt there a danger that the heat generated will futher harden the shaft?
Re: Best way to machine ball screws?
You get real good fit and it is very tight and as for the hardening i would say nothing that i noticed. When i did my last lot of screws it worked really well, chucked the screws in lathe and set it up so that the turn was opposite to the grinder. It comes off really quick and you will be surprised how accurate you can be with it. Make sure the doors and windows are open when you do, dust everywhere :-)
Re: Best way to machine ball screws?
Hi Ross. Try Chester tools,they sell add on quick change tool holders in different sizes. Dont know what size mine is, pretty sure its their piston T1, has dovetail slots, but its big and fitted to a 11 inch lathe and never had any trouble. Be prepared to bore them out / make a bush to fit you cross slide post. Most after market posts will need some tinkering to fit. You wont look back if you get one they are wonderful, life IS too short! Re machining ball screws, some are ground out of very hard stuff! Cheaper ones are case hardened and light hand grinding will remove this easily. The simple route is to cut em off and make a collar to attach to a custom turned end. If you mean to turn the actual screw ... v diff to get the linearity you need. Many people refer to a ball screw but mean an acme screw with an anti backlash nut (apologies if you mean a ball screw!) The are plenty of suppliers of acme screws, Chester sell spare lead screws for their lathes and they are relatively inexpensive (compared to say a replacement myford lead screw) and you can buy acme taps. You can cut a long acme thread but unless you have spent a lot of money on a very accurate lathe.... it wont run well and the backlash nut will bind in certain places. TC indexable are good but go off quick, horses for courses, TC isnt always the best. That all sounds rather negative, its not meant to be so sorry! Shame you dont live next door mate, we could stare at the problem for a bit over a few beers and I'm sure all would fall into place!
Re: Best way to machine ball screws?
Hi Ross,
I had someone else machine my ballscrew ends to fit into an angular contact bearing block - that is 16mm ballscrew turned down to dia12 for bearings, then M12x1 for nut, then dia 8 for motor coupling. 3 off cost me £50, and he did a great job, turning it around in a couple of hours whilst I visited relatives.
He was John S from Nottingham - it has taken me a while to realise it, but I'm sure it is the same John S from Nottingham (HobNob man!) who posts on here, so hopefully he'll chip in soon ! I saw his advert for machining services on the Arc Euro website.
Best of luck
Re: Best way to machine ball screws?
Thanks everyone
Quote:
Hi Ross. Try Chester tools,they sell add on quick change tool holders in different sizes. Dont know what size mine is, pretty sure its their piston T1, has dovetail slots, but its big and fitted to a 11 inch lathe and never had any trouble. Be prepared to bore them out / make a bush to fit you cross slide post
Sounds like thats what i need. its for my Halifax which an atlas clone and is 10" swing. mounting shouldn't be a problem as I have a tee slot table to go on the cross slide:smile:
I do mean ball screws but only machining them for bearings etc.
Quote:
I had someone else machine my ball screw ends to fit into an angular contact bearing block - that is 16mm ballscrew turned down to dia12 for bearings, then M12x1 for nut, then dia 8 for motor coupling. 3 off cost me £50, and he did a great job, turning it around in a couple of hours whilst I visited relatives
I have considered just getting some one else to do it but wheres the fun in that? its also quite expensive for me to get it done locally.
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Shame you dont live next door mate, we could stare at the problem for a bit over a few beers and I'm sure all would fall into place!
yeah I seem to be in the wrong part of the country for engineering.:nope:
Re: Best way to machine ball screws?
OK so thanks to all for the advice, Ive narrowed it down to the piston type from chester or Ebay number 290448499618.
But I have also seen this from RDG, who I have dealt wit in the past and found them very good.http://cgi.ebay.co.uk/ws/eBayISAPI.d...MakeTrack=true
This uses a cam system to lock and looks like the expensive Dickson ones http://www.lathes.co.uk/latheparts/page13.html
it also the looks like it would also fit on the compound slide which apparently is the easiest way to set up for screw cutting. (after hacking through the hard stuff)
Any one have a preference or experience with either type?