[CoCoMedic]

I am interested in getting a milling machine such as the one below:
http://www.woodstockint.com/Products/M1005
or this one:
http://www.grizzly.com/products/G9959
My initial objective was to use it for woodworking projects. However over the past 6 months I have become more interested in machine and metalworking projects as well, and as a result I would also like to use it for cutting a larger variety of metals and steels. THe machine already has a belt drive system, with a speed range between 400 to 5000 rpm. However would it be possible to add a variable speed drive to this mill, in order to obtain a wider variety of speeds? I would love to be able to change speeds simply by dialing it in with a handle or knob. That way I could switch from low speeds for metals, and then jack it up for the high speeds that work well in cutting woods. How difficult would this be? What kind of a speed range could I get? What difficulties would I have to overcome?

[Bubba]

CocoMedic,
Yes, it is possible to add a VFD to one of these machines IF you change the motor out to a 3Phase motor and add the VFD. Based on a quick check of the web sites, it appears these units origionally ship with 3450 rpm motors. If you want to run metal cutters, I would suggest replacing with a 1750 rpm motor and if it is a proper inverter rated unit, you should be able to run it twice rated rpm with the VFD to keep the high speeds (also useful for small cutters in aluminum). I would also keep the origional pulleys so you can keep the torque curve at low rpm.

Hope this helps.

[Al_The_Man]

BTW the VFD can run off 220v single phase in, (3phase out).
I converted both of my shop Excello Knee mills, these had the original 2 pole motors (1750 rpm) and I run these at 120hz which doubles the rpm.
The Varispeed pulley was replaced by timing belt drive.
They already have a two speed gearbox.
Al.