Ok guys I got my mill the micro mill/drill from Harbor Freight. I got a 3 axis driver board Xylotex, 3 Powermax Steppers 116oz, kdntool cnc retrofit kit (on order). I was looking at some pictures of this mill retrofitted and I have seen some who changed the motor mounts and spindle to belt driven, I was wondering why? Also is there a kit or an easy way to set this mill up to be able to dial in the rpm's and have a display to show me what rpm excatly I am running at? I've disassembled the mill and working on the gibs to get them as smooth as possible is there anything else i need to check or do to the machine while I wait on the rest of my stuff to come in?

Nathan Firebaugh
Fireball Lures

I changed mine to a belt drive to increase torque. The screws were changed to ball screws to remove backlash and increase accuracy. I’m also added a ball screw to drive the z-axis.

I was originally considering retro fitting my Harbor Freight Mill as well, but after talking with one of the engineers over at GeckoDrive, changed my mind to build a unit intead. Point he brought up was that the lead screws on it are 16tpi, which translated to something along the lines of 1750lbs of force at the milling bit.... which would roughly translate into many broken end mills, or pretzeled lead screws. Thats why I'm building an entirely separate machine for cnc, because the H.F. mill doesn't have all that much in the working area to warrant buying replacement lead screws to get down in the 5 - 8 tpi area.
The other concern was that with such a steep tpi, it would mean that the steppers would be running hot ( constantly at high rpm's ) and the stock screws would get pretty hot as well.
-just some thoughts, I'm still learning this too......

my financed .02

arthur

http://cnczone.com/showthread.php?s=&threadid=237