Cutting Acme threads is pretty much the same as cutting Unified threads . The only real difference is that the compound is set to 14 1/2º instead of 30º and you can't take as deep a cut because there is more of the tool in contact with the work. If you can cut a Unified thread you can cut an Acme thread, there's nothing magic about it.
Tom
(09-26-2012, 09:20 PM)TomG Wrote: [ -> ]Cutting Acme threads is pretty much the same as cutting Unified threads . The only real difference is that the compound is set to 14 1/2º instead of 30º and you can't take as deep a cut because there is more of the tool in contact with the work. If you can cut a Unified thread you can cut an Acme thread, there's nothing magic about it.
Tom
I think I've read that with acme threads you feed straight in rather than at an angle like you do with a Unified thread. Is that true?
Ed
(09-27-2012, 05:53 AM)EdK Wrote: [ -> ] (09-26-2012, 09:20 PM)TomG Wrote: [ -> ]Cutting Acme threads is pretty much the same as cutting Unified threads . The only real difference is that the compound is set to 14 1/2º instead of 30º and you can't take as deep a cut because there is more of the tool in contact with the work. If you can cut a Unified thread you can cut an Acme thread, there's nothing magic about it.
Tom
I think I've read that with acme threads you feed straight in rather than at an angle like you do with a Unified thread. Is that true?
Ed
Nope. The angle of the compound is just different, 14 1/2º instead of 30º.
Square threads are fed straight in and those are a pain to cut. Sort of like parting with a twist.
Tom
(09-27-2012, 06:24 AM)TomG Wrote: [ -> ]Nope. The angle of the compound is just different, 14 1/2º instead of 30º. Square threads are fed straight in and those are a pain to cut. Sort of like parting with a twist.
Tom
Yea, I can see where square threads would definitely need to be fed straight in.
Hmmm, this talk about acme threads reminds me I have a project that is going to need an acme thread cut. I need to make a tailstock to use with my spin indexer for supporting work between centers. It probably doesn't need to be an acme thread but it'll be a good opportunity to get some experience in cutting them.
Thanks,
Ed
Ed, remember the nut that will follow.
It can be done though, I cut a new nut for the cross feed screw on my 12x36, came out pretty good ( it's left hand too).
(09-27-2012, 06:50 AM)stevec Wrote: [ -> ]Ed, remember the nut that will follow.
It can be done though, I cut a new nut for the cross feed screw on my 12x36, came out pretty good ( it's left hand too).
Good point Steve. The nut would be the challenge compared to the screw. I'll have to think about that one.
Ed
If the nut is large enough to get a decent size boring bar through, it won't be too bad. If not, you could always make the nut out of bronze and make a tap out of the screw. Real Acme taps are available as well, but VERY pricey.
Tom
If, your making a screw Ed, make it a bit longer and leave enough slightly oversize Like skip the final cut and you'll have the makings of a tap.
(09-27-2012, 08:48 AM)stevec Wrote: [ -> ]If, your making a screw Ed, make it a bit longer and leave enough slightly oversize Like skip the final cut and you'll have the makings of a tap.
That's certainly an option. Thanks.
I think I can weasel my way out of this though. I believe I have a piece of 1/2-10 left hand acme at home that I can use for the screw. That doesn't solve my nut problem
though. I also have matching left hand acme nuts that I might be able to turn down and make a press fit into the sleeve. I'll have to start a thread about that project once I get to it.
Sorry to David for hijacking his thread. Shame on me!
Ed