Fingers crossed it'll cut ally

[blackburn mark]

your right jonathan, i meant a helli ESC in govenor mode... iv switched it off, i read somwhere that it would hold revs under diffrent loads, sadly, no joy on that one, its just a slow wind up to speed to stop all the power stripping gears betwean the motor and the main helicopter rotor... maybe it will hold revs when it is flat out?

on the brighter side, my motor has enough power to drill 10mm holes through 40mm of alli without getting particularly hot :) the ESC gets a bit warm though but nothing to drastic... fingers crossed

that motor you have would be wasted as a router !! it may even be over kill for milling alli on your 3 axis... id stick that one on a bike and start doing wheelies up and down your street and use a similar size as mine to mill alli, i really cant see my 3 axis out performing a 2000w spindle

ps: you get extra points for getting your holes wrong on a CNC :) yeeeee Haaaaaawww !!!

[Jonathan]

on the brighter side, my motor has enough power to drill 10mm holes through 40mm of alli without getting particularly hot :)

Is that without a pilot hole? i.e. removing a 10mm diameter cylinder? If so that requires roughly 310W (at 'reccomended' rpm). What rpm did you use?

that motor you have would be wasted as a router !! it may even be over kill for milling alli on your 3 axis... id stick that one on a bike and start doing wheelies up and down your street

Yeah, I bought it to put on my bike, but that's not happened. I'm thinking of replacing the pathetic motor on my sieg C3 lathe with it. I still think it'd be good on my router for aluminium.[/QUOTE]

ps: you get extra points for getting your holes wrong on a CNC :) yeeeee Haaaaaawww !!!

I think I got a dimension slightly wrong, either that or I should have used a bigger clearance hole in the first place.

A long time ago in this thread I mentioned a method of controlling the ESC from mach3 using the spindle PWM output....so I thought I'd give it a go.

Basically I connected the ESC up to my normal radio system on the model car and used multimeter to measure the duty cycle, and frequency, of the signal at neutral, full reverse and full throttle. I measured 45.6Hz and 5%-6.7%-8.5%. That's a bit annoying as it's only using a small range, but nevermind.

So then in mach3 I ticked 'PWM control', 'Use spindle motor control output' and set 'PWMBase frequ.' to 46hz, and finally set 'Minimum PWM' to 5% (i.e. full reverse).
Then on the motor outputs tab I enabled the spindle and just set the step pin to the one I wanted (in this case pin 2).

Then I went to Config-->Spindle pulleys and set the max rpm to 1000 and left the rest. (more on why I chose 1000 rpm later)

Next I connected multimeter to the parallel port pin to check it was outputting the right frequency, and that the max voltage didn't exceed 5v since more would damage the ESC. Both were fine (I'm using laptop to test, which probably explains the port being 5v) so typed in 'S100 M3' to set the spindle moving at 100rpm. That way if I use the override slider 100rpm corresponds to 10% duty cycle, or more usefully 67rpm is 6.7% ... i.e. neutral.

Now I set it to 67rpm connected one of the parallel port ground pins to the black (ground) wire on the ESC signal connector, and pin 2 to the signal wire (the other side of the 3 pin connector). Esc initialised fine, so I upped the spindle speed a little with the override thing in mach3 and the car promplty shot off the desk :exclaim: and drew briefly half a kilowatt from the battery.
Connected it back up, and yes it works fine.

There's one issue though, at the moment 67rpm is motor stopped, and 85rpm is full speed - in this test 85,000rpm!

I think in my case I'm not going to be too worried about sending the motor backwards, so clearly I can use the forwards only setting on the ESC which makes things a bit simpler. You'll find the duty cycle values for your ESC will be slightly different - use my neutral (6.7%) as a starting point and you can do the normal calibration thing on the ESC to set the endpoints.

I'm sure with a bit of fiddling I should be able to get the RPM values in mach 3 to correspond to actual motor RPM, I'll have a think on that one and let you know.

Hope that helps, ask me if something isn't clear...

PS It took me a grand total of two bits of wire stuck in the parallel port to do this - you MUST check that the parallel port doesn't output more than 5V (5.1 in my case but that's close enough). If it's more then use a couple of resistors as a voltage divider to reduce it. Either way I strongly advise optically isolating the thing.

[blackburn mark]

What rpm did you use?

i didnt clock the revs... just dailed until it was cutting sweet, less than 1000rpm id guess