This is a first look at the 2 speed belt drive to fit the LM-45 or MD001 IH clone Industrial Hobbies / Charter Oak Automation ZAY7045, Grizzly G0484, Pen Tools DM-45, or PM-45, RF-45 type of benchtop CNC milling machines.

I added some picture of the 2 speed belt drive here.

http://s1294.beta.photobucket.com/use...

This design is made for a 1750 RPM 4 pole 3 phase motor.

The motor plate is milled to fit a 145TC 143TC or 56C face frame motors with a 5.88" bolt circle. I can make a larger motor plate to fit the 182/184TC motors with the 7.25" bolt circle but you would have to special order it. The Euro mount motors will also fit on the standard motor plate but they are rare.

The pulleys are 5" in the rear and 6" in the front for the big ones and around 2.5" for the small ones. The 60Hz speed for low range with a 1750 motor is 700 RPM and for high range it is around 2,900 RPM. You will have vary good low RPM torque to below 20 Hz or around 150 RPM. Tapping and drilling with larger bits will be no problem.

For the top RPM you can do a nice 4000 RPM at 80Hz input and if you bog the motor slightly it moves into the range where it makes more torque so it should not stall vary easy. Some say it is safe to go 100% over speed with a standard non VFD motor and if you do it will give almost 6000 RPM but really for most Aluminum cutting you will be using 2 to 3K RPM which is right in the meat of the power band. With carbide cutters I almost always cut at over 1500 RPM so high range is still good for steel.

The stock spindle bearings are tapered roller bearings which are vary strong but if they have much preload at all they run vary hot at higher speeds. I would recommend replacing them and going to angular contact bearings if you plan on running the mill for long runs at speeds over 3000 RPM. You can lower the temperature of the stock bearings by lowering the preload and going to synthetic grease.

I am making these to sell. If I use the name Arizonavideo at CNC Zone, you can PM me or contact me with my email. The sell for $599

More pictures are posted here.

http://s1294.photobucket.com/user/ari...

Thanks for looking

Dave

Email

davedaxx1@yahoo dot com