And yet, it was still a surprise when I stumbled on a motorized coping saw for sale on eBay. And no thanks to the two beers inside me at the time, I ended up buying the saw. It arrived yesterday. It is a curious creature.
Patented in 1941 by Albert J. Dremel (yes, the namesake of Dremel), the Dremel Moto-Saw is a remarkable if commercially unsuccessful piece of engineering. After reading the patent application (check it out on Google Patents), I was impressed by its ingenuity.
Like a traditional coping saw, the blade is held in tension with a spring action. The heel of the blade (the part by the handle) is on an armature that looks and works like a diving board at the swimming pool. The armature is attached to the frame of the saw at one end and juts out over a big electromagnet in the handle.
Plug the saw in and pull the trigger and the armature moves quickly back and forth as it is attracted to and repulsed by the electromagnet.
You can even vary the stroke of the saw by turning a knob that adjusts the position of the armature, just like you would adjust the springiness of a diving board.
How does it work? Well I plugged it in, pulled the trigger and the Moto-Saw made a noise like a gaggle of angry bees being shorn by an electric razor. This is normal.
The armature indeed moved rapidly in and out. I was ready to be impressed.
The only thing stopping me was the fact that this saw came with no blade. And standard coping saw blades won’t work. I’m guessing that this saw uses pin blades that have about 2-1/4″ to 2-3/8″ of blade between the pins.
I started making my own blades this morning, but I’m going to need a 3/64″ drill bit and some punches first. So I’ll put that on the list for my next trip to the hardware store.
Now before you dismiss this saw as a piece of war-era lunacy, take a look at this 2007 patent from the Robert Bosch corporation (yes, that Robert Bosch).
– Christopher Schwarz