[Mini-MillX2]

I have a DynaCNC 4'x8' router/plasma table and want to convert the current Z axis to ball screw. The current Z axis has a 1/2" 10 TPI 1 start lead screw (LH) with a bronze nut. The bronze nut and lead screw are making alot of noise no matter if it is lubed or not. Last week the Bronze nut acutally unscrewed itself ruining my part. Anyway I really want to upgrade it to a ballscrew setup to make it more reliable.

Trouble is I can't figure out what ballscrew setup to upgrade it to that doesn't change the Turns Per Inch. I can only seem to find 2 start 1/2" 10 Threads Per Inch that would create a 5 Turns Per Inch down from 10 Turns Per Inch setup effectivly doubling my speed from the current setup and reducing my effective torque, correct?

Am I just not finding the right setup or does one not exist?

[louieatienza]

I have a DynaCNC 4'x8' router/plasma table and want to convert the current Z axis to ball screw. The current Z axis has a 1/2" 10 TPI 1 start lead screw (LH) with a bronze nut. The bronze nut and lead screw are making alot of noise no matter if it is lubed or not. Last week the Bronze nut acutally unscrewed itself ruining my part. Anyway I really want to upgrade it to a ballscrew setup to make it more reliable.

Trouble is I can't figure out what ballscrew setup to upgrade it to that doesn't change the Turns Per Inch. I can only seem to find 2 start 1/2" 10 Threads Per Inch that would create a 5 Turns Per Inch down from 10 Turns Per Inch setup effectivly doubling my speed from the current setup and reducing my effective torque, correct?

Am I just not finding the right setup or does one not exist?

While that may be partially true, the fact is a ballscrew is about 90% efficient, while that 1/2"-10 single start ACME with bronze nut maybe 20-30%. The problem is it will backdrive when you turn off your machine, causing the Z to drop. You may need a brake of some sort to hold position when there is no power to your drive motor.

You can get a ballscrew with a lead of 2mm, but it would most likely be a ground ballscrw, and expensive, unless you can fiind one on eBay. The efficiency is still about the same so it can still backdrive.