I dont do alot of fabrication at home but enough that I wanted something a little bit easier and not as loud as a cutoff wheel or grinder. I always wanted a metal cutting bandsaw but they are expensive except the little HF ones. I also wanted to be able to cut other things as well like wood or foam or whatever. So I kept my eye out and got an old Rockwell vertical bandsaw locally for 50 bucks!
http://i178.photobucket.com/albums/w276/RatBone/misc/conv1.jpg

It was in good shape and worked, its not the oldest style with a beefier frame but it will do what I need.
http://i178.photobucket.com/albums/w276/RatBone/misc/conv2.jpg

Now I heard that you could use a treadmill motor and variable speed drive that comes on them to convert a wood bandsaw to go slow enough for metal. I found a 1.5HP 90VDC motor , transformer and variable speed controller from a treadmill on Epay for 50 bucks! You could probably troll garage sales and get one for next to nothing.
http://i178.photobucket.com/albums/w276/RatBone/misc/conv3.jpg

The old 1/3hp AC motor just mounts on a pivoting plate under the saw. I took it off and the DC motor bolted right in. It even had the right size pulley on it.
http://i178.photobucket.com/albums/w276/RatBone/misc/con4.jpg
http://i178.photobucket.com/albums/w276/RatBone/misc/conv5.jpg

You can see a little set screw on the pulley. You can adjust the pulley about 2 inches on the shaft to line up with your saws pully where you need it.

Now this controller was small enough to mount in a regular handy box from a hardware store. I got a blank cover for it to mount the speed control (potentiometer) in. The card has L1 and L2 pins on it. this is where you hook up the 120VAC. I got an 8 foot pigtail from the same hardware store and a 1/2inch compression fitting for the handy box to put the cord in. Now there are 2 more pins on the card that say A1 and A2, this is where the DC motor hooks into. But you have to have 1 of the DC motor wires go through the transformer before it plugs into the card. I think it can be either one because I tried it both ways and it worked. Now the 2 wires can go to A1 and A2. To make the motor go CW or CCW just switch the A1 and A2 wires. I ran the 8 foot pigtail and the 2 DC motor wires through the 1/2 inch comprssion fitting and into the handy box. I grounded the pigtail ground wire to one of the screws that I used to mount the box to the saw leg.
http://i178.photobucket.com/albums/w276/RatBone/misc/conv6.jpg

The transformer I mounted on the saw leg across from the handy box. Now the DC motor also has a ground wire and I ground that wire to one of the screws I used to mount the transformer.
http://i178.photobucket.com/albums/w276/RatBone/misc/conv7.jpg

Here is the handy box mounted with the speed control mounted on the cover. The DC motor has what I think is a small balancer and fan on this end. I think I will take off the fan but leave the balancer. I will make a guard for this end of the motor.
http://i178.photobucket.com/albums/w276/RatBone/misc/conv8.jpg

Here is the finished saw! (except for the guard) It doesn't look much different than it did.
http://i178.photobucket.com/albums/w276/RatBone/misc/conv9.jpg

When you plug it in the motor doesn't even move till you turn the dial a little bit. You can go from 0 to 4800 RPM!! A DC motor has the about the same torque at any RPM so you can slow down to do metal (with a metal blade). I put on a blade that had about 14 teeth per inch and it went right through this 1/8 x 1 1/2 steel bar.
http://i178.photobucket.com/albums/w276/RatBone/misc/conv10.jpg

If I pushed real hard I could bog down the motor but I just let the blade do the job and it went through real nice. If I was converting a full size wood saw I would probably use a bigger HP DC motor. Any way good luck on your project!

Nice writeup!

Wow! Never thought/knew treadmills used something so simple! Nice writeup BTW. Thanks for sharing :beer:



Chris:cool2:

they work good on lathes and other things you want lots of variable speeds also!

What's the biggest motor you can get from one?

Very good idea. I looked at converting my drill press to a DC motor a while back but buying everything new was way too pricey. Never would have thought to look for a treadmill.

I think you could get a DC motor with bigger HP out of something else and use the variable speed drive from a treadmill to control it. You can find DC drives and motors on Epay all the time.