One of the interesting features of a frame saw is that one can use it as a push saw (with enough tension on the blade) or as a pull saw. Which is more appropriate, if there is such a thing?
I thought about this while in the process of resawing some beech, a bear of a process when the board is a 13.5″ wide slab. I had the saw in at roughly 45-80 degrees and it seemed to me that it was much faster pulling than pushing. What could have caused this, other than not enough blade tension?
As pretty much anyone will tell you, during ripping, your saw teeth are acting as little chisels and are hopefully shaped as such. But then wouldn’t the factor of grain orientation come into play?
- When pushing into a board with the tooth side of the blade at an acute angle to the board, you are generally sawing with the grain, as you would with a plane.
- When pulling out of the board, you are sawing into the grain, invoking tearout.
If you tear out, is that a bad thing? It seems to me that it would be faster because your saw would be continuously digging itself into the fibers. Of course, it would be tougher work. Would it also help avoid tracking the grain?
Think of the Japanese timber saws (stuff like the Kobiki Nokogiri or whatever its name is) — these are notoriously quick pull saws.
Well, I think I’ll do some more sawing to see what I like in practice. Probably with something other than a 13.5″ wide chunk of beech, though.
[Edit: Check out this blog post that a friend dug up for me. They’re ripping chestnut logs in a demonstration of traditional techniques, letting lots of people try. The big saw is called “Oga Kobiki” (大鋸) or “Daigiri” or something like that. Check out the angle they’re using in the wood versus the rake angle of the teeth.]
When I am sitting on a sawbench and have the wood wedged below like Bob Easton, I orient the saw to cut on the pull – the action is like rowing, so the cut should be the same as the stroke for a rower! When I put the timber in the vice oriented vertically I tend to cut on the push stroke.
You can sidestep the issue if you use an ECE blade which allows cutting in each direction.
I think a lot of it depends on how you hold the work Brian, and what muscles are used from that direction.
The “wedged below” benches that Jeremy mentions can be seen here:
I pushed with that arrangement and really built up my anterior deltoids. 🙂 I’ll try pulling the next time I need to do that kind of work; it might make better use of the stronger back muscles.
THANKS Jeremy for mentioning the ECE saws. I had not seen them before, and the “Farmer’s” blade looks interesting for bidirectional use. The last bidirectional blade I tried had much different geometry and was agonizingly slow. This one might be a lot better.
More about them here:
Good luck with the beech Brian.
I don’t know why, but frame saws for resawing intrigue me. Perhaps my New Year’s resolution should be to build one this year.
It seems like a fun niche that has been understudied and relatively little understood.
Besides that, I really do need one since I don’t have a bandsaw.
So I did a little more sawing this morning, this time with some yellow-poplar/tuliptree/lireodendron tulipifera/whatever you want to call it. The grain orientation is definitely a factor here, not just whether you push or pull. When going against the grain, you get a sort of choppy feeling that eases up as you near a 90-degree angle. When going with the grain, the sawing action is much smoother, but it definitely doesn’t cut as smoothly.
Jeremy, the ECE saw you mention reminds me of the rake angle. That sort of saw would definitely cut in both directions, but given that it’s not a very aggressive angle, how quickly and at which orientation? And sharpening would probably need to be done with a feather-edge file. All of this said, one can theorize about this stuff all day long, but actually trying it out would probably be more useful.
The blade I’m using now does not have a terribly aggressive rake angle. I would like to resharpen it at some point with a zero-degree rake angle and see how much of a difference it makes.
I still have a lot more sawing to try out. Unfortunately, I’m not going to have much time for anything in the next three weeks.