[CNC7777]

Hi

Im in for a openbuilds 1500x1500 and want lead screws on all axis.

Will a 1/2-10, 5 start ACME do a good job for a allaround machine capible of doing detailed 3D work aswell as some production runs on big projects and V-carving whit this screw?

I dont have the time at the moment to sit down and learn enough to take a good dessision on the subbject myself and need some input.

(Sorry my poor english grammar)

[ger21]

With those long lengths, you'll probably have issues with the screws whipping at higher speeds.

[CNC7777]

Will that result in bad acurrasy of the machine?

Another noob question on ACME is should lead-screws be tensioned or compressed when installed? I have seen both and am a bit confused.

[mactec54]

Will that result in bad acurrasy of the machine?

Another noob question on ACME is should lead-screws be tensioned or compressed when installed? I have seen both and am a bit confused.

If they where to have anything, it would be tension, they should never be under compression, these 1/2 acme lead screws @1500 long could only be used for a very lightweight machine like a printer would not be much good for anything else, unless
you used a them with a rotating nut you may be able to do light carving work

[Tutu]

Get a ballscrew and ditch the lead screw. I have a 1400m 1605 ballscrew with BK12/BF12 fittings was ~$100 delivered from China I feel a lead screw is the wrong choice here given the cheapness of ballscrews,

You want a 1610 or better a 2010 but costs will still be under $150 with fittings.

there's a calculator for screw whip but I've run it at 4000mm/min with no issues so far but I should have used a 1610.

[ger21]

I have 1500mm 1/2-8 2 start acme screws on my machine, and the whipping causes stalling at about 600rpm. My Y axis has a 1000mm screw, and it doesn't whip at all, even at 1000 rpm.

If you can tension them, it should be better.

[CNC7777]

Thanks for the answers so far guys. The main reason i was thinking leadscrew is the simplisity, in my head just buy a slightly to long screew and cut it to length, throw a delrin thread-clamp/thread-cupler in each end with a washer against a thrust bearing and go right? Also as mention earlyer i have been told a 1/2-10, 5 start should be good combination of speed/precission/torque. I se machines like cnc shark as example using lead screw on their extended bed models and i dont think it is a thicker screw than this? This is my first cnc router, probably gonna build a better bigger and more ridgid one in the future when i am more in to cnc routers and calculating screw pitch and other aspects, so verry high productivity/speed is not a absolute nessesary at this point, just get going with a desent and simple/cheap machine that work ok and take it from there.

Just to clear up a couple of things: are leadscrews usualy tensioned and if so are there torque spec charts on this? Same with ballscrews does these need to be tensioned?