View Full Version : Bandsaw project....

11-18-2009, 06:28 PM
In the spirit of the "What do you do in your shop" thread, I thought I'd post something I did a while back that I have been meaning to share here. Apologies for the marginal photography, I was in a hurry when I took them.

I was given an old, almost ancient Craftsman 12" bandsaw as a gratuity for helping a friend do a small bit of rewiring on a table saw he bought. I got only the saw, no motor, stand or anything else. I know wood-to-metal bandsaw conversions get discussed regularly here, and am aware that it is something of a compromise, especially with a old low-end saw like this one. But I had nothing to lose, and I always have wanted a vertical bandsaw to compliment my power hacksaw for all of those vertical bandsaw type jobs that crop up. This is what I came up with:

Needing to slow it down to speeds reasonable for metal cutting, I came across a 1 HP, 90V DC motor with a right angle 6:1 worm drive. Rescued from a dumpster, it needed only new brushes and the commutator cleaned up to restor it to working order. I had another dumpster rescue and repair item, a KB DC motor controller, that complimented it nicely. I housed it in an old motor controller box I had:

At full speed (~1750 RPM) the output from the worm drive measures 290RPM. I coupled that to the saw through a pair of 4 step pulleys. The driven one has 3"-4"-5" and 6" steps, and the saw shaft has 5"-4"-3" and 2" steps. It looks like this:

With the motor at full speed this gives me four speed ranges with top blade speeds of 546 ft/min, 911 ft/min, 2064 ft/min and 2733 ft/min. In any range, I can then infinitely vary the speed. The workable minimum I have found works out to be about 60 RPM or so at the output shaft. With the 3:5 pulley reduction that works out to be about 113 ft/min which has proven to be plenty slow for cutting the steel stuff I have run through it.

On the top end, it is plenty fast for cutting wood, aluminum and other soft stuff. Though it seems to spend most if the time in the 911 ft/min range, speed changes are quick as the belt is tensioned using a turnbuckle. A couple of twists and the belt is loose:

I replaced the bearings in the saw, and the lower wheel shaft in order to make it longer to accommodate the outboard bearing you can see in the above picture. I'm not sure that was necessary, but it seemed like the thing to do at the time for some reason.

No doubt this saw comes up pretty short in the rigidity department. If you run a blade with a lumpy weld in it, you can actually see the frame flex a bit as it runs over the wheels. But it does cut straight and well. I takes up little floor space. In total I have under 20 bucks into this thing, most of that for one of the step pulleys, the belt and some odd hardware. Everything else came from the trash, or the pile-O-stuff. The funky orange frame that makes up the base was part of a supermarket wine display rack, also a dumpster rescue. I have yet to add a belt guard , but that is in the works. Also needs paint to make it more machine-ey and to cover up my crummy looking welds.

As you can see from the pile of dust on it, it has gotten regular use!

-Al A.

11-18-2009, 07:02 PM
Thanks for sharing. You went to a lot of trouble to rescue an old POS, but I admire your ingenuity and resourcefulness. I hope that someday I'll have time for more projects like that.

11-18-2009, 07:03 PM
Nice write up and photos Alan. Thanks.

I have been eyeing off my son's Wood Bandsaw for a while;)


11-18-2009, 07:51 PM
My buddy picked up a similar saw at the scrapyard. We used a gearmotor to run the thing at about 100 fpm, as he wanted it for only metal; he already had a bandsaw for wood. It worked out well, and he reports using it regularly.

Good job, Alan!

11-18-2009, 08:22 PM
Alan...That is a neat old saw. You did a really nice job of it with the motor setup. I have thought about that kind of thing for an old, cheap, cast iron wood saw that was given to me. I have and old transmission from a 50's era washing machine that is shifted from direct drive to about a 10:1 ratio. Hopefully, this will work. If not I will look at gearmotors. This is the kind of work that is really rewarding to do, taking an old, unwanted thing and making it useful.

11-18-2009, 08:28 PM
Looks good to me,first metal cutting saw I had was a late model Crappyman 12" with a reducer made from ten speed bike parts.It probably had more flex in it tha yours,but it still worked.

11-18-2009, 08:45 PM

That came out great. I was also given a free saw of similar vintage and style (only a 3-wheel version). I think I may have to do something similar to what you have done.

andy b.

11-18-2009, 09:44 PM
Thanks, All.

I have no idea how much time went into this, but it was not so much, and was all enjoyable time messing around in the shop. Did most of it a bit at a time as parts and time cropped up. This also used a number of those things that we all tend to have around "because I'll be able to use that for something..." I'm sure most all of us here have our share of those things.

Pretty happy with how it worked out. Where I work we have a DoAll and a big Grob, this clearly is no rival to either. But it does get the job done for the sort of work I do. I have cut 3/8" steel with it. Not fast, but not with any undue effort. If I had a choice, I'd have started with a more stout machine. But this one fell in my lap so I figured that I had little to lose outside of some pleasant shop time.

Gotta get the my salvage blade welder dialed in next. Still working on that.

Thanks again for chiming in.