Hello all,
Broke my bow saw last weekend, and I figured that rather than simply replacing the damaged blade and missing rivet, I'd make my own out of hard maple and a replacement blade. Obviously, this isn't a terrribly hard job, but I figured I'd see if anyone has got any pointers that I may not have considered.
My general idea is to make a basic H-frame with the blade on one side, and a threaded rod on the other (to adjust the tension with a wrench- I know there are some methods that use a cable, but I figured the rod would be a little bit more solid) So as far as I can see, I have only two or three things to consider here- first is the joinery for that middle crossbar; my inclination is to use a loose mortise and tenon joint with a wooden dowel to keep it from falling apart when changing the blade. I figure a little bit of slack will allow the joint to move when the blade is tensioned (no glue in the joint, obviously) The second consideration is a matter of basic design- what I've used in the past is the standard metal bow saw, but I've seen that the older saws have a frame that extends below the blade on one side. Generally, I'm using the saw on logs that are laying on or near the ground, so I'm afraid it could get in the way, but if there is a compelling reason to keep that extended frame, I'm sure I can work with it (my guess is it helps to keep the blade plumb, but I couldn't say for sure) The third is whether it's useful to leave a set of handles on the top of the saw above the tensioning rod, or if that is simply too high and unsteady when you use it. Weight isn't much of an issue, just performance.
So, can anyone spot any holes in my plan that I may have missed? I'd hate to use the last of my rock maple, and then have to smack myself upside the head because I forgot something really important. I can always try again, but it's nice to do it right the first time. I've also got a good plank of 4/4 ash that I could use, if it's a better wood for the job (It has more spring than maple, IIRC.)
To try to anticipate the inevitable requests for more info, the saw will be for cross-cutting logs for turning blanks because I don't have a chainsaw and can't afford one right now (at least, not one worth having). I'm making it, and not buying it because I want a deeper throat depth than the bow saws at the hardware store provide, and the standard hardware store ones have a tendancy to dig into my little finger (I have big hands, and the blade flexes upward when cutting) The blade I'll be using is a standard 36" bow saw replacement blade. Finish will be tung oil, just 'cause it's a little more hand friendly than poly, and won't get milky if it gets wet like shellac does.
If it works out well, I'm considering a frame saw for resawing short planks out of some of the trunks I come across (hard to find spalted wood at the lumber supplier, after all) so any good links to nice rip blades for a hand saw would also be appreciated!