*Subsurface contamination modeling...not swimsuit.
Yeah, it does. But I wasn't.
I decided instead to prototype a bow saw. Here's a fine example of one. It's typical on homemade versions to use a length of bandsaw blade for the blade. I happened to have an old one sitting around, so I was in business. Typically you drill a hole in either end of the blade and run a pin through it to attach it to the frame. The only problem is that these holes have to be at fairly precise lengths to make it work. I don't have much faith in my precision, so I thought of a work-around. The brace of my saw would meet the two arms at pivoting mortise and tenons that would allow for a large margin of error in overall blade length. If you don't understand, keep going; a picture is worth 1000 words.
I had a nice scrap of maple lying around. Looks like a potential saw, doesn't it? Lilah thought so too.
Then I cut it down...
Then I just eyeballed a shape for the arms and bandsawed them.
Then I chopped my mortises into the arms where they join the brace. Next I needed to cut the inside curve along the mortise shoulders. Here's how I got uniform curves:
Next it was time to cut the tenons for the brace. I'm not aware a tool that would work really well for cutting a curved shoulder, so I just roughed it out and then trimmed away:
this and this.
Anyway, once the brace was finished I had a rough bow saw:
Now it was time for the hardware. I bought some 8mm bolts and ground flat sides opposite each other on the ends:
Next I needed to cut a slot for the blade to run between the two flat sides. Trying to start a hacksaw cut on the end of a bolt can be quite a trial so I helped myself out by using a sharpening file to start the groove:
Then I just used a hacksaw to cut the slot. Notice how the vise is used as a guide for the cut:
Then I drilled one side of the slot bigger than my pin bolt and the other side slightly smaller so that the bolt could tap it itself:
Now time to put it all together:
I also have to say that the pivoting mortise and tenon doesn't work great. Sometimes the whole frame "racks," like a big parallelgram. It's a little hard to explain in words. Oh well, it was a good effort.
My wife also did some woodworking today:
Maybe tomorrow I'll start that modeling project...