I made a turning saw based off of the design TFWW has online. It gets an awful lot of use. Here’s some of my observations:
1) Ash should be fine. Mine is made from red oak – very similar. I think straight grain is more important than wood choice because of the forces involved.
2) The tapering of the arms helps reduce weight. On a non-turning saw weight might be helpful. On a turning saw weight is your mortal enemy. Aside from making you work harder for the cuts, most of which aren’t going straight down, it will cause the whole frame to succumb to gravity and rotate on you. The grip I use is to hold the stubby handle and pinch the frame at the same time to help prevent this (can’t remember where I learned this, Frank Klaus video I think). But the more weight on the frame you have, the more effort to pinch and keep it from flopping. This is especially the case when you need to hold the saw horizontal to earth to make the cut.
3) The reason to put the mortise on the arms is the same as above. If you put through mortises on the stretcher it will have to be a lot thicker and that’s more weight. And again, weight is your mortal enemy.
4) Most of the internet will tell you that you need the strongest string on the planet. 8000lb Kevlar quadruple braided deep sea finish line! And double it up 18 times!!! No. Just no. The string should be WEAKER than the arms of the saw. If you have a failure, you want the string to break; not the arms. An arm breaking will bring everything to a grinding halt and now you have a new project (making a new arm) instead of the current project you are working on. I use regular jute twine, which is 7lb line I believe, and I double it up once which can give plenty of tension on the blade. It’s not just a matter of tension on the blade though. It’s also that when you are pushing through insanely thick stock you are putting compression forces on the bottom of the arms (below the stretcher) and if there’s enough force, something will have to give. I have done this once going too aggressively (who has patience?) on 3” stock and it was a crazy loud CRACK! And things exploded. My initial thought was “no not an arm!!!!” But all the parts were fine. It was the string. It did what it was supposed to do and all I had to do was cut a new length of string and tie a not – I spent most of the couple minutes finding the bundle of twine.
5) I did not use the Gramarcy hardware. I cut the heads off bolts, cut a slot, cut a groove (to keep it from twisting in the handle), drilled a hole, and epoxied them in. I use a bandsaw blade (a lifetime supply of blade material for $10) and drilled a corresponding hole at each end of the length I used. I cut a finish nail to hold it all together. If you look carefully I put a kink in the nails so they don’t fall out when the tension is removed, but I can still put them out if needed. One advantage of the Gramarcy pins is that they can accept blades that are 1/8” I think, whereas if you have to drill a hole 3/16” is about as small as you can go. They also look prettier, although I think you have less options for blades which might not really matter at all.
6) I went through a couple blades trying to figure out what worked best. I settled on this one
https://www.amazon.com/gp/product/B0...?ie=UTF8&psc=1 which is 3/16, 10tpi, 0.25 thick. I learned the hard way not to go thinner than 0.25 because the blade will twist too much when you make a tight turn. I also learned that there’s no reason to go below 10tpi because I’m basically never ever making a finish cut with this thing. Anything visible will ultimate be hit with a file, or spokeshave, or sandpaper. Aggressive tpi and set both make it easier to cut faster and also make tighter turns. The only reason I see to go smaller than 10tpi is if cutting really thin stock, like 1/8”, or in some other very fragile situation. I’ve cut plenty of ¼” with no problems at 10tpi.
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