Uses a 1.1Kw/1.5Hp motor with tach feedback so the controller can keep the speed constant. It is setup for 6000 rpm, and will do 500 rpm with more than enough torque. I have tested a 3/4 drill bit in aluminum with a small pilot hole and it didn't bat an eye.

The belt drive utilizes a 32 tooth spindle pulley and a 64 tooth motor pulley using HTD5 belt, all purchased from Econobelt. The belt is currently a 9mm wide belt because that was all that was in stock. A 15mm belt would fit better, but the 9mm seems strong enough. The belt length is 560, and my mounting plate uses the back two holes from the original cover and two new ones. I turned 4 2in long standoffs. Vibration is nonexistant and while not whisper quite, i can actually hear my music while running at 6000 rpm.

Also, I made a simple coolant plate that is 1/2 in thick aluminum, pocketed .1in deep throughout, with two deeper holes for 1/4 in copper fittings and topped off with .25 in aluminum. It works great as a flood coolant dispenser and works awesome in helping cool hot spindles.

The second post shows the arceurotrade half belt drive conversion. It works ok, and was good up to 1/2in drills in aluminum in low gear, but the gears were pretty loud. Also, a nicer plate and a lower spindle sleeve are in the works. I intend to do something very similar to a coolant outlet like the one in the haas mills thread, but enclosed, so I dont have to worry about seals except at the fittings and base. I will run the coolant though both pieces, which helps cool the head and spindle bearings.



Also, after 2 years of machining, 24hrs a week, at 5000 - 6000 rpm, the spindle bearings are still silky smooth. Runout isnt great, but it never was. Around .0002 turned by hand, around .001 when wailing at 6000 rpm.

Very Nice! Did the pulleys require any machining to make them fit?

Nice job. 6000RPM would be nice...maybe I'll have to put some thought into doing a similar thing.

Yes the spindle pulley required a bit of boring and then I pressed it onto the original spindle gear after turning off the teeth and using the lathe to make it 1.40in in diameter. It was a really tight fit, and with some heavy duty epoxy, it wont move a bit. The drive pulley just required a quick drill throught the hole to enlarge it to the motors shaft.