Sherline CNC mill upgrade questions

[H&NERY]

I have a Sherline Model 2000 CNC mill, I would like to upgrade the mills lead screws, I see A2Z offers Kerk screws at a 4tpi, has any one had any experience with this, also would I be better off to install their extended travel x-y bases, at the present time I am happy with the travel of the Sherline for what I am building, but that could change. The other question, I am running the Sherline software, will that be compatible with 4tpi screws? What other upgrades have anyone done? I don't have room to upgrade to a bigger mill.

[RET]

Hi,

I bought a "turnkey" Sherline CNC mill about 10 years ago now and although 3 years ago I built a bigger & better replacement for the mill, I still use the Sherline computer & software with the new Machine. I don't know anything about the screws you want to use, but there are two issues for what you want to do.

First, because the new screws are only 4 threads to the inch instead of 1/4-20 tpi., if you direct connect them, the existing stepper motors won't be strong enough (1 turn of the stepper moves the table 5 times as far so it will take up to 5 times as much torque). I used 5/8 dia. 5 tpi. Thomson ball screws to drive the new machine and used the existing stepper motors with a 4:1 timing belt reduction so the computer saw no change. Because I also used 1" dia. Thomson shafts on support rails, there is almost zero friction on the ways. This gave me a lot more "useable" torque on the steppers.

The second issue is if you are going to direct connect them, you have to go into the 4axismill setup and change some of the numbers to get the right travel for the stepper motors. That isn't hard to do, but you need to be careful when you do it.

My new machine works very well and I'm pleased with it. It now has 16" X travel, 9" Y travel & 9" Z travel. Best of luck on your change, just think it over carefully before you make the change. If you are interested, I posted a picture of the new setup on another recent thread in this forum.

Richard Trounce.

[gwerhart0800]

I CNC'd my sherline 5400 years ago. I kept the original lead screws and just changed out the trust bearings. You might also want to poke around the A2Z guy's web site, he sells both extended X, Y, and Z kits and precision lead screws.

http://www.a2zcnc.com/machinetools.asp