After being inspired by a thread started by Ross Bleakney, who was looking for a folding saw around 4 ounces (http://www.backpackinglight.com/cgi-bin/backpackinglight/xdpy/forum_thread/84231/index.html), I wanted to start a thread on ultralight saws in general. I'm interested in what other people use and/or have made and their experience with them, good or bad.
For the purposes of this thread, I suggest the following definitions:
"Ultralight" for a folding or fixed blade saw is anything under 6 ounces.
"Ultralight" for a bow saw is anything under 12 ounces.
I've used and made a few now, with the following results.
Folding Camp Saws
I have a Gerber folding saw (apparently discontinued) that I have used for years on trips where wood burning is permitted. 3.1 oz, 5.25" blade length. Chain saw style teeth that cut on the pull stroke. Quite effective for such a small saw. Cut through a scrap 4 x 4 from my wood pile in 2.5 minutes.
Reciprocating Saw Blades
David Thomas posted some info and photos in the other thread showing several saws, including two he made by modifying existing saw blades. One from a piece of band saw blade, and another fashioned from a reciprocating saw blade. I bought a couple of aggressive looking reciprocating saw blades and ground finger cut outs to make handles. One cuts in both directions (7" blade, 1.7 oz with red oak handle), and one cuts on the pull stroke (8" blade, 2.3 oz, Plasti-Dip handle). Nice and light, but not very effective. The fat blades have a wide kerf, which requires cutting a lot of wood. I tried cutting that scrap 4 x 4 from my wood pile, but gave up after five minutes when my arm got tired and I was less than half way through.
Pruning Saw Blades
Next I modified a fixed blade from a pruning saw. Nice chisel point teeth that cut on the pull stroke ("Japanese" style blade). Ground a hand grip into the base and coated it with Plasti-Dip. Because of the shape of the blade I started with, the handle is parallel with the blade. 11.5" of teeth, 4.1 oz with several lightening holes drilled in it. Cut through the same 4 x 4 in 1.5 minutes.
Then I modified a wider fixed blade from a different pruning saw. The wider blade gave me room to grind the handle at an angle, which made a huge difference in its effectiveness. Cut through that 4 x 4 in 45 seconds. 10.5" of teeth, 4.1 oz, no lightening holes yet. When I get the lightening holes drilled I'm pretty sure I'll be able to shave off .1 - .3 oz. (I'm waiting to drill the lightening holes until a drill bit sharpener is delivered, having burned through three cobalt bits to drill seven holes through the previous pruning saw blade.)
I have ordered another fixed pruning saw blade which is even wider, so I can grind the handle at more of an angle. Will post photos and info when I get it done.
I have not used a bow saw on camping trips previously because of their weight. There are several available now that weigh around a pound. Sven and Sawvivor are two. Steve at Suluk46 made a prototype 12" bow saw that weighs less than 3 oz (http://www.suluk46.com/RandD%20-%20RD32%20Ultralight%20Carbon%20Fiber%20Buck%20Saw.html), but it is not available for sale at this time.
I am currently also working on a couple of bow saws. One uses a 12" blade and the other uses a 24" blade. I'm making them from carbon fiber tubes cannibalized from fishing poles and golf club shafts, with reinforcements made from aluminum tubing at the hard points (where the blade attaches and where the tubes join). Below is a picture of my progress on the 24" saw. Will post photos and info when completed.