my build from the start

[irving2008]

Well, having done the calcs on my mill, and measured the actual friction coefficient with a digital spring gauge, I know the likely motor is going to be in the order of 3Nm to achieve 1300mm/min cutting and 2500mm/min rapids. If I hadn't measured it then the estimated friction coeff of 1.1 would have suggested a 4Nm motor. I'm working on 36v @ 4A as I have a 36v, 12A PSU to hand.

The point here is that every mill is different. You need to weigh the table and measure the friction coefficients to avoid overegging the solution. I am not fussed about cutting speeds as long as they are reasonable... its still going to be faster/more accurate than I can do it by hand and since I dont have suds or one-shot oilers I'm going to have to be there to spray/oil as it runs.... Its not going to be working hard enough to justify doing those mods...yet...

[Jonathan]

I know the likely motor is going to be in the order of 3Nm to achieve 1300mm/min cutting and 2500mm/min rapids...

Those numbers are similar to what I got on my milling machine with the same motor. I've never cut at over 1000mm/min, and that was with a big cutter (http://www.youtube.com/watch?v=iC7lX..._order&list=UL). The 2150rpm spindle limits the feedrates I can use. I started off with 2500 on the X axis (see http://www.mycncuk.com/forums/showth...ll=1#post12790 post #19), but have gradually reduced that to 1800 over time. Now I've taken the motors off to use them on the router. It will still do more than 1800, but not 2500...I think the ACME screw or something has worn a fair bit. Time for ballscrews perhaps-that should make it a bit faster due to the efficiency.