UHMW for ACME Nut?

[Thinwater]

I just got about 60 lbs of UHMW 1 1/2" thick drops from a machine shop. I am nearing the completion of my new CNC router roughly based on a JGRO but made from all AL and Steel. Is this good stuff for making an ACME thread nut out of? I have a couple of 5/8" 8 TPI ACME threaded rods that I will use and not having to buy a nut it a good thing.

I am considering cutting off a section of the threaded rod and milling the flutes in it to make a tap from.

JIM

[planekrazie]

I used it. The only problem I ran into was, when It was cold in my shop it liked to bind. I had to place a heater under my cnc table to heat the acme screw then it worked like a charm. Just a thought.
Steve

[surplusdealdude]

Jim, generally I wouldn't recommend UHMW for a nut because it is affrected by cold ( as Steve noted), it's very soft and close tolerances are difficult to get.

But, since it's free, what have you got to lose?

BTW, making the ttap out of the rod is a good idea - drill the hole just a tiny bit larger than you usually would to prevent the binding that Steve noted.

[Thinwater]

I was hoping that due to its softness and slightly flexing nature it would hold the shaft better and not have any (much) baklash. I have a couple of regular steel nuts for the rod but none of the brass ones mounted in the little brackets like everyone sells.

I did not want to go through making one, making a mount and get it all mounted then have everyone tell me why it was such a bad idea, so I asked first.

I may go with the steel nuts and try and use software in Mach to fix any that it has or rig up a spring loading mount.

Thanks,

JIM

[surplusdealdude]

I'm not sure that it's 'slightly flexing nature' is going to work in your favour. UHMW is extremely resistant to compression, so if it gets too small for the thread, it'll bind like a (fill in the blank). I'ts not likely to be forgiving that way.

You might be alright as long as you give it a little 'wiggle room'. Not sure what that's going to do for your accuracy, though.

[Thinwater]

Thanks, I will use the steel nut with a spring loaded anti backlash mount.

Now to figure out what to make out of the UHMW.....

[surplusdealdude]

Here's something kind of neat that someone did with 1 1/2" thick material;

http://www.phoenixwood.ca/forum/index.php?showtopic=31

[harryn]

Thin water - I am looking for some strips of UHMW if you want to sell some.

[Thinwater]

harryn, If I have peices big enough for you you can have a shoe box full for shipping cost. Most peices are the corners cut of of a square peice that a circle was cut out of. They would mill down to about 1 3/4" squares. I also have a couple of circles about 7" around. If this is not big enough see the eBay store from the signature line of the above posts from surplusdealsdude. He has a bunch of it for sale on his eBay store for good prices.

JIM

[surplusdealdude]

Thank you, Jim - I was going to mention it, but it's much nicer when someone else does it for me. :-)

BTW, If you don't see the size you want, you can PM me - I have other material that isn't listed - especially round stock of UHMW ( in colours, too! Up to 6" diameter!)

[pminmo]

I've used uhmw for nuts. With both bad and good results. If the screw is rough at all, or has a burr in one place, the uhmw wears fairly easily. If the screw is a high quality screw, they work fairly well. It would depend on how much a machine gets used.