Theres what your looking for, I bought his power drawbar plans and they are pretty good.
I was wondering if you could use a die grinder as a spindle, I have seen many 25,000 Rpm die grinders both electric and air powered. I want to make a cnc router table but want a high speed spindle option. Just curious if anyone has tried this or if it's even possible to let a die grinder make that type of cuts say in aluminum.
Not really looking to make one just thought could you buy a die grinder with a 1/4" collet and use it as the spindle, using in turn 1/4" shank end mills and other tooling. This would be a high speed spindle option if it would work almost everyone has air compressors to run it and some of them I have seen industrial die grinders are .5 HP some up to 80000 RPM's. I want to build a cnc router type table style. I ran across this company who makes cnc mills which run micro tooling and have 60000 rpm .4 Hp spindles and I wish to make a similar less expensive machine. http://www.daytrondynamics.com is the website of the routers really fast and really expensive.
You better have a really big compressor to run a die grinder as a spindle. Also I think a die grinder will have way too much runout to run really small tooling. Small tooling will break very easily with too much runout. Read this: http://www.precisecut.com/tutorials/spindle_runout.htm
Mach3 2010 Screenset
(Note: The opinions expressed in this post are my own and are not necessarily those of CNCzone and its management)
You can get .125 (1/8th) collets for a die grinder. Runout (TIR) is an issue with ALL collets and you should measure runout if you're holding a tight tolerance or, as Gerry's article pointed out, if you're running small tools.
Its easy to measure and adjust a collet's TIR if you have a little patience and use the three points method. I use this method to pick up (indicate) a bore or hole I've drilled or to pick up a tooling ball. You can use it to pick up anything with a cylindrical face or body. It takes some practice but I can indicate a hole or tool (mostly reamers) in about 2 min now.
The method; Indicate the x-axis (both sides of the tool or bore facing the x-axis) so that they are equal. Then indicate the tool on one side of the y-axis so that it equals the the x-axis you just indicated. Once the three sides have been indicated you can rest assured the fourth side of the tool is equal. Light tapping in either direction on the tool shank, based on the runout, is generally accepted for indicating reamers/drill bits/End mills.
Another tip; Only move the tool, gantry, or spindle half the distance of the TIR your indicator is reading. Then measure again. I promise if you do this in the right direction you will be very close to zero TIR on your next reading.
Good luck, I hope this helped.