I needed a small metal cutting bandsaw for pre-cutting stock for my 3 axis CNC milling machine but I did not want to spend a lot of money on a new one. I had been checking craigslist when this little gem came along. It’s a Rockwell/delta 10″ bandsaw (here’s a copy of the owners manual for this saw) that takes a 71 3/4″ blade. It has a nice rigid cast iron frame, metal band wheels, and an open drive mechanism making it perfect for a conversion. The major difference, outside of the blade itself, between a wood cutting bandsaw and a metal cutting bandsaw is the blade speed. Wood cutting bandsaws run too fast for metal cutting. To convert over to metal cutting duties I needed to reduce the speed of the band wheel by about a factor of ten.
My initial inclination was to use a larger pulley to slow down the blade but some calculations determined even a double pulley reduction would not slow it down as much as I would like. I went through my list of parts on hand and decided to employ an EPL series motion control gear reduction unit with an 8:1 reduction ration. That would slow the bandsaw blade down with the pulleys I had on hand to a good speed for cutting metal.
The gear reduction drive is designed to bolt onto a face mounted motor and as such has a female shaft mount on one end. I quickly turned a spindle from some steel stock to 24mm on the gear drive end and 5/8″ on the other for the pulley. The goal of this project was to quickly have a good metal cutting bandsaw with what I had on hand and minimal spend. Coming back to the discourse on design, I was designing with what I had available for this project. It may seem a bit ridiculous to use such an expensive part on a $50 saw but I figure I can always pull the gear reducer later if a more pressing need for it arises.
I decided to reuse the original belt that came with the saw. I upgraded the stock pulley to the largest one I had on hand, and drilled some holes into the legs of the stand to mount the reduction drive. The gear drive needed a bracket to support it on the other end. One was fabricated out of 1/8″ steel stock. This arrangement required the motor to be relocated which was accomplished by drilling 4 new holes in the correct location on the base of the stand. Be sure to check the motor rotation and reverse it (usually swapping wires inside the motor wire box) to correct it if the blade is going the wrong way.
The new drive belt is a 4L290, as I happen to have 3 of them on hand. I only had to buy 2 parts in addition to the bandsaw itself for this project. The first was the small pulley that is mounted on shaft of the gear reduction drive. I purchased a 2 3/4″ dia pulley with a 3/4″ bore at my local tractor supply store. Tractor supply has a good selection of motors, pulleys, and belts in stock. Not a lot of hardware stores carry these items in this day and age. I had to bore out the pulley’s 3/4″ bore to 20mm on the lathe to make it fit onto gear reduction unit output shaft.
Wiring on old tools is horrific and when I opened the electrical box up I was thankful I didn’t get electrocuted when I tested out the saw. I replaced all of the 40 year old scary wiring and upgraded the switch with a modern unit.
The only other part I purchased for this project was a small spacer for the handybox that encloses the wiring for the bandsaw. These are available at Home Depot for less then a buck. The new switch I selected did not fit in the enclosure, requiring the spacer. I used the CNC mill to cut the opening in the switchplate.
The finished tool works well and I’ve already cut several linear feet of aluminum stock on this saw, with a 6 tpi wood blade in place. I’ll be ordering up some good bi-metal blades in the near future. I am very happy with this little project and foresee myself getting many years of good use out of this saw.