I bought this second hand last year and it's awesome (1st proper mill!), but I've been spoilt by the variable speed treadmill motors on my lathe and drill press, so I've been waiting awhile for the opportunity to add a treadmill motor to my mill.
The 3 usual challenges are 1. how do I stop the flywheel (LH threaded usually) from spinning off in reverse, 2. how do I go from the poly-v pulley on the treadmill motor to the 1/2" V section belt on the mill (or whatever tool it's going on) and 3. how do I gear down the treadmill motor (4700rpm) so that spindle speeds don't go through the roof?
1. is easy with this motor as it is rare in having a keyed and pressed on flywheel
2. and 3. are somewhat related and involve either adapting the intermediate shaft/ countershaft of the tool to poly-v or putting the smallest possible V pulley on the treadmill motor, somehow. I couldn't adapt the intermediate pulley to poly-v as there wasn't the space and the rework would have been rather tricky (though it was easy to take this approach on the lathe). I could have turned down the flywheel poly-V pulley and press on a 2" diameter V pulley, which is what I did on the drill press, but that would have precluded the full range of motor>intermediate pulley ratios and I wanted to try something different this time. Thus began a time consuming, convoluted and thankfully successful project to make an arbor adapter that would also take the original motor pulley if I wanted to use it. I was also an interesting experience turning the mystery stainless that I used for the flange. Beautiful finish but OMG what a squealing racket.
pulley was pulled from my "this might be useful oneday" pile of pulleys. Crazy amount of porosity in the casting. Detroit original
mounted to the motor, a "2.25hp" motor, that works out to ~1 1/2 real world hp.
on firmer ground now as I've done a couple of these already and they're pretty straightforward.
The guts are an MC-60 treadmill controller, courtesy of a user from another site called Maxheadroom - thanks! Power cable, main switch and fuse holder from some treadmill I salvaged. Cheapo 4 digit ebay tach and 9V wall wart guts. DPST lighted switch for controlling power to the controller. DPDT with center off switch for FWD/REV. Choke for the DC power line to the motor. 5k pot (also thanks to Maxheadroom) for speed control, with a large dial off some random salvaged peice of equipment. Oh, and a 2 port wall plug at the bottom for ancillaries.
looks complicated but it's pretty straightforward - board is already bolted in with heatsinks on the back, main switch, cord and fuse are installed on the left. Controller switch (top left), wall plug and wall wart for tach (bottom right) are connected to the main switch, controller switch then connects to the controller board AC power plugs. Trim pot is plugged in to the left of the board. FWD/REV switch is plugged into the DC output plugs - one line connects to the choke and the other goes straight to the motor.
FWD/REV is easy - inputs come in at the center, outputs come off one side with that side connected to the other in an X. Super simple, but I ALWAYS wire it the wrong way round, every time. Thankfully that's as simple as swapping the plugs on the board or the wires on the motor.
Back of the front panel showing the controller switch, FWD/REV switch, tach and wall wart (hotglued to the panel, it works!)
Another perspective
motor mount, from ultimate scrapbinium - I dug the large piece out of the ground at the scrap yard, which is why it looks so tatty. nice to have a 2 x 1 1/2ft piece of 1/2" alu plate lying around though.
mounted up
installed (you can even see the lathe controller box in the background!)
other side
I since found a shorter belt in my box of random belts. The original was an A32 which did fine for the low speeds, the AX28 I found fits perfectly for higher speeds like the one shown. Before the magnets I casually placed on the spindle pulley were flung off and attached themselves to some part of the mill, the best ranges I found were 0-250, 50-500 and 150-1200rpm with one more higher ratio to be tested above that (I'm guessing 300-2000 or so). I wasn't able to run the motor flat out in the higher ranges as the intermediate pulley sounded like it was going to fall to pieces, so that may be a future project, but that would probably net me another 200rpm or so.
Haven't used it in anger yet as I was tired of being in a 100F garage and I had some data analysis to do, but a face mill arbor is next on the list so I'll have a play with it on that. Pleased as punch with it though, this'll make life alot easier.
but hopefully close enough. It's a BUD box with the MC60 heatsink bolted to the box with some extra heatsinking on the outside. Hasn't gotten beyond hand warm yet.
