question about leadscrews and misc. X1 stuff...

[WRMorrison]

Well, I purchased an X1-type from HF a week or so ago, and I'm supposed to be receiving the extended X and Y kits from LMS tomorrow. I will be CNC'ing this machine before too long (probably within the next 6 weeks or so), and I want to replace the lead screws.

I know that ballscrews are the way to go, but I've also seen that some people are getting decent results at replacing the original screws with stainless acme screws (1/2-10). Can I really get decent performance out of these replacements acme's? If so, should I try and fit the largest size I can in there (like 5/8 or 3/4), or will 1/2-10 be good enough? Also, is there a reason to stick with a thread pitch of 10?

I figured that if anyone can answer my questions, the good folks here can.

-WRM

[gun_mike]

i recently replased the 1/2-20nf leadscrews on my mill with 1/2 10tpi acme screws, and wow what a difference. the machine cuts so much nicers and the handles are easyer to turn. I was looking at ball screws at first but it came down to the cost, so i decided one 1/2 10 stainless acme. I didnt buy any leadnuts.. i made them on the lathe with actetal (delrin) they seem to have no backlash....yet lol hopfully. I used to radial grove bearings for each lead screw so i could preload them. This may be the mayjor reason for the smoothness.Anyways my table is an after market x y table about the same size as the X1's table

mike

[WRMorrison]

Thanks for the reply Mike, that sounds pretty much like what I'm wanting to do. I'm going for precision rolled ACME screws, stainless steel, 1/2-10, 2 starts (5 turns per inch = .200 traver per revolution), and delrin nuts. If for some reason the delrin doesn't work out, I already have some brass available. Did you make your own acme tap, or did you purchase one?

-WRM

[gun_mike]

i was unable to find a tap comercially so i just made a threaded section on the lathe from cr steel took along time to get the pitch/thread angle the same as the 10tpi acme. then i just cut 4 channels in it with an angle grinder and tappered the tip on the sanding disk. I tried tapping in brass at first just to see if i had made it correctly.. no success. i think you might need a two step tap for that. it does cut the delrin like butter and theres just about zero backlash. It wouldnt be hard to add another leadnut and attach it to the first one with small screws this would give you some adjustment for backlash and wear.

Mike