In March, 2010, I started this project. Prior to this, I had been following Matthias Wandel's band saw build (the first one) with interest and thought I would try to build my own. That is the way many projects start: a source of inspiration to spark the creative process, and it's this and the collected know-how that make sites like Woodgears.ca so valuable.
I started with the frame. Having the ability to work metal, I wanted to make it from steel. Steel can produce a strong frame that isn't overly bulky, if correctly made. I studied some commercial band saw designs, mainly for overall dimensions and structural details, and came up with the basic frame design.
The main support member for the frame is a piece of 2" x 3" thick walled rectangular tubing. This would be the post that runs vertically on the left side of the frame, and the rest of the frame components would be welded to this. This main support post provides the bulk of the strength to the frame, so it was important that it be of adequate size to resist the bending and twisting forces the frame would experience.
For the majority of the rest of the frame, I used thick walled 1" x 1" square tubing, salvaged from an old (rather large) garden trellis. The stock was in rough shape, with the main obstacle to using it the thick layers of paint that I would have to grind off:
A lot of work to clean it up but the benefits are twofold: I save money on raw material and I get rid of something that is no longer useful or attractive.
Seen here, the first frame member is clamped in place, ready to be welded:
When welding parts together, I have to be mindful of the fact that the heat from the weld and shrinkage of the cooling weld will distort the metal, throwing it out of alignment. To avoid this, I tack weld the part in place on opposite sides of the joint, thereby minimizing this distortion. With the part tacked on all four sides, I can complete the weld, alternating from one side to the other and checking the alignment as I go.
The bottom part of the frame takes shape:
And with the addition of three more members, the lower frame is done. As 'rustic' as it looks, it is very strong and very accurately made.
Adding a metal 'skin' to the lower frame. This I've screwed in place with self drilling sheet metal screws. I don't want to take the chance of distorting the frame by welding this skin in place. Again, I'm using recycled steel, this time the material is from window cut-outs on a heavy steel door:
Getting the upper part of the frame constructed. The bottom member is angled to reduce the free span of the main post slightly, and because it looks a bit better than square across. This angle doesn't reduce overall cutting capacity, since the upper blade guide will hang below the member on the right side.
The flat bar in the middle is the upper wheel axle mount.
The skin added and the upper wheel mount finished.
This saw differs from most others, in that the blade tension is controlled by raising or lowering the lower wheel / motor assembly. The upper wheel is only responsible for tracking, and that is done by bending the flat steel bar that the axle is attached to forward and back, via a hand wheel at the back of the unit:
A hand wheel will be mounted to this shaft, to facilitate tracking. The mechanism is very simple - by bending the flat bar back, the axle shaft goes up off horizontal, pulling the upper wheel back out of vertical alignment and the blade tracks toward the rear of the wheel. By bending the bar ahead, the opposite happens, the wheel rotates forward out of vertical and the blade tracks forward.
Motor Subframe Assembly
The motor I wanted to use for this was one of the two treadmill motors that I bought at a surplus store. The other I used in my Disk Sander project. These are rated at 1 hp, and turn at 1725 rpm - very good for a band saw of this size. Although untested at this point, I thought it would be worth the risk of using this motor, since it was very low cost.
To mount the motor, I constructed a frame with a pivot, to allow the motor to swing up and down to tension the v-belt:
This frame was then attached to the main motor assembly subframe, seen here partially completed.
The upper section of the subframe supports the lower wheel drive mandrel. Seen here the unit is mostly complete, pulleys of the correct size have been mounted and the right length v-belt is installed:
Buoyed with confidence from doing such a splendid job, I powered it up, to check the performance. It was then that I realized that this motor turns counter clock wise and could not be reversed (all of the start winding wiring was inside the welded frame of the motor, making it impossible to rewire without cutting open the frame).
So, my options were to either turn the motor around (pointed out to my by Matthias Wandel, although too late at that time) or get another motor, one that was reversible. Since these treadmill motors were still of unknown quality, I decided to get a new motor:
I then made a mounting frame for the subframe and bolted it to the frame of the saw (too many frames?). Between the mounting frame and the motor subframe assembly, I used drawer slides, to allow the motor assembly to move up and down to tension the blade. In hindsight, I can say that doing it this way was not really a good idea. Making the upper wheel move up and down to tension the blade would have been quite a bit easier:
The saw is now ready for wheels.
Speaking of wheels, I removed the motor subframe from the saw to 'turn' the wheels true and put a crown on them (I did the upper wheel this way as well). The wheels are made from 5/8" melamine, with the rim thickened with a second layer to make the wheels 1-1/4" thick. Although on the heavy side, these are very flat and stable:
With the frame complete, I gave it a paint job. This is a base coat of flat Tremclad rust paint (white) overcoated with water based clear satin polyurethane. The result is a very tough, durable finish. It makes quite a difference to the appearance, cleaning it up nicely.
The motor subframe assembly I painted flat black. Tremclad rust paint again, though this time in a spray can:
I fashioned a belt and pulley cover from sheet metal and screwed it in place. This picture shows the oversized mounting flange I made and welded to the mandrel shaft to better support the lower wheel.
With the wheels mounted:
Unfortunately (or not, who knows) at this time in the build process I suffered 'burn out' - I just needed a break from the project, as I had been working on it (and thinking about it) constantly. I decided to put the project on hold for a time, to regain motivation to push to the finish.
Little did I know how long it would be before that motivation returned.