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!