Lead screw Help

[psjflyer]

Hello all, and thank you for having such a great website to learn from. I am in the process of building a Jgro design, I will be posting images later. I have been studing other designs. I have a question, which acme screw is the best for speen and resolution. I have read until be eyes are bleeding and I have not found anything on which is the best. I have thought about the 1/2 10 multi start and then I read that the lionclaw design was using a 1/2 8 2 start. I look real good on the flow of what is was doing. Please help


Thanks
Gerald

[Lee Roberts]

1/2 10 seems to be a common size used, you will need to give us a better idea of what you plan to do with your machine, sizes, lenth and so on.

[ger21]

Originally Posted by psjflyer I have a question, which acme screw is the best for speed and resolution.

As you increase the screw lead (inches per turn), you decrease resolution.
If you're going for maximum speed, go with a 1/2-10 5 start. Even the 5 start will more than likely give you more resolution than you need.

Joe is even trying some 1/2-8 8 stat with apparently good results.

[CarveOne]

Ger21 is correct, but I wouldn't get too hung up over calculated resolution numbers unless you are designing microchip manufacturing machinery.

If you calculate resolution in the 0.00000001" range it means nothing if your drive system actually has 0.0001" backlash. Assuming that you actually can measure 0.00000001" backlash in your system, it means nothing if you are cutting wood, MDF, Depron, aluminum, etc. if the surface texture of the cut material actually has 0.0001" variances at any two points of measurement.

See, nothing to worry about. For DIY wood cutting machines 8 start lead screws are just fine.

CarveOne

[Grunblau]

My lead screws are 5/8"-8 2 start (4 TPI). I am very happy with this setup so far... I would suggest going with 1/2" though as there is a lot more support for this size (dumpster nuts etc..)