A photo of a project in progress in the top secret zenkinetic research labs. Here we see a gutted backsaw in the process of getting a spine-ectomy. You will note the very high tech multi purpose research platform – it can convert from a lab slab to a table saw in mere seconds. The goal of this “research project” as to replace a really cheesy, very wimpy spine (next to the Sharpie) with the spine from hell, two 1” x 1/8” x 12 1/2” steel plates. The before and after photo is of the old spine sitting on top of the new. What I’ve learned so far:
- That much steel is heavy. You really don’t want to press down during a cut; put the saw on wood, push and wood turns to sawdust. Which is good because it takes two hands to lift the saw.
- When you are tired, wired on caffeine and thinking about 10 seconds into the future, try real hard to work on projects that can be shoved into the recycle bin with little remorse.
- Clamping the spine with the handle would seem to be necessary with a spine this long and heavy. Otherwise, the weight flops the blade from side to side relative to the handle when the saw isn’t vertical, the blade is too flexible to keep the saw straight in the handle.
- If you drill the saw plate, your drill had better not stall. If it does, the plate acts like it gets really hard, really fast (work hardens). On this plate, I had to sharpen the drill several times; sometimes I could drill cleaning through, boom, done. Other times, at half way the bit would stop and I would be hosed; hot plate, dead bit. I’m guessing I need better pilot holes, better steel in bit (M2/4?). Or just switch to a hole punch.
- I now have an opinion why some saws are canted (the saw plate is rectangular, the spine is rectangular but sits lower on the front than at the handle: Maximize cutting depth and stiffness. The less tall a plate is, the stiffer it is, which is good. A big fat spine also stiffens the plate. Combine a short plate and tall spine then add a handle and you have no cutting depth. If you don’t [want to] drill through the spine and attach the handle to it, raising the spine is a easy way to leave room for handle screws. The front of the saw benefits the most from the spine, the closer to the handle you get, the less spine you need as the plate becomes shorter and less likely to bend. Making a canted spine makes more economic sense but if materials are cheap and you already have a process and machinery in place, … A non-rectangular spine also might not look as nice.