Category Archives: Kobiki

Ripping Boards from Logs with a Maebiki Oga

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Sawing a board from a log with a handsaw is not only possible, but quite an interesting venture.  If you can love your maebiki oga and snap a good and true line, board lumber will proliferate. I’ve been putting some pretty good hours on my maebiki oga the last week learning to use it, and I’m still far far away from proficiency, but have garnered some useful insight. Up in the Colorado rocky mountains there’s so much beetle kill pine that at least one person dies every year from a tree falling on them while hiking. Suffice it to say, plenty of logs can be had for the asking, assuming you can get them out. Right now I’m still sawing through the beetle kill that came from our property.  This is “blue stain” lumber.

Kobiki Saw Horse

I’ve seen a few pictures searching the interweb of Japanese kobiki at work. There’s lots of shots of sawyers starting the cuts at the top of the log, but nary a photo of finishing the cuts at the bottom. My work holding was really shoddy the last time I posted about using this saw, and I’ve definitely upgraded.

I made this ‘A’ frame saw horse from 5″-8′ pressure treated fence poles. Its tied together with cotton rope, with a few diagonal braces nailed on to keep it from racking side to side. I can start my cuts with the log lying at a shallow angle across the bottom rest. I also used a few pieces of heavy rebar and turned them into log dogs, also a necessity if you want to saw lumber. They do a great job of holding the lumber in place. I’ve been getting by with the three I made pretty well.

Maebiki from Below Log

Standing behind the tip of the log gives a smooth start, being able to see the layout lines on the top and tip of the log. From there its quite comfortable to saw while seated under the log. I’ve been placing another piece of lumber on top of the log being sawed to stand on at a more comfortable angle and keep from smudging up my chalk lines. It also dampens the chatter that can occur when sawing under the log. I’d really like to get a sumitsubo Japanese ink line. Chalk just doesn’t seem to throw well on the irregular surfaces of the log. Canting off two sides of the log allows me to get a more certain layout, at the expense of the widest boards in the center of the log.

Maebiki oga from on top

If my line starts drifting on the opposite side I’ll move to the top of the log and try to correct. I know I said earlier that wedges are your friends, and they are, but you want to use as little wedge as possible to keep the plate from rubbing. Open up the cut too far the saw may want to lay to one side and start cutting at an angle. Sometimes you can rescue a cut that is going badly off the line by wedging the board to an angle that allows you to correct back on the line. Just make sure that you’ll be able to straighten the saw plate back in line with your ink/chalk line once you’ve made the correction. The plate on this saw is so, so very deep, and it corrects like a super tanker at sea. You have to start reversing the direction of your correction before you actually reach it or you end up over correcting and binding as you saw drunkenly back and forth either side of the line.

Maebiki Oga finishing cuts

Here is an eight foot log on the horse, finishing my cuts down to the end. I had to use two screws through the waste lumber either side at the bottom to keep the end from slipping off the horse when sawing. This log position is awesome, because I can saw letting the weight of the maebiki help itself in the cut. You can saw from either side of the log without having to flip it, as well as saw while seated on the back side. Any time you can sit down while slinging a big piece of steel like this, do it!

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A good strong puff of breath keeps my line clear of saw-dust.  My poor western back is not used to working like this, and it takes some getting used to.

Its been a real challenge getting this saw optimally sharpened and set. Over the past week I’ve sharpened it about twice a day for a full day of sawing, but never adjusted the set. This lead to increasing problems tracking on my cut line and binding on the saw plate. As a shoji maker all of my saws have very minimal set, and I strive to keep it that way. But green lumber and a thick plated saw like this require much more than you’re theoretical .004″ tooth set.

So how much set does a maebiki oga need? Good question. There is so precious little info out there in English on hammer setting saws. You just have to get a cheap saw and give it a try.  I’ve been slowly adding set in with a hammer and anvil. My anvil is a piece of 4″ CR ROD 12″ long. It weight at least 50 lb, so makes a decent anvil for hammering on saw plates and peening rivets, whatnot. Probably could do some light forging on it if I ever get my forge set up.

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The hammer is reground from a tack hammer. Its probably a bit light for the job. I’ve only found one picture of a guy hammer setting teeth on a maebiki oga and it looks like he uses a cross peen without ridges, peening at a right angle to the long axis of the tooth. That would allow the user to work with the saw plate supported on your lap. Why don’t I just find that picture.

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The existent hammer setting marks on my saw suggest that the above photo and a straight cross peen were used.

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However, this hammer does work just fine. The face is flat and the ridges are quite shallow, made with a couple passes of a swiss triangle file. I have the saw teeth resting on a straight chamfer at the anvil edge. I want to change it to more of a radius to match the smooth curve that hammer setting leaves in the tooth. I finally think I put enough set back in the saw. Now its just a matter of practice.

Sawyers unite! I know of at least two other woodworking bloggers who have talked about getting a maebiki oga. Do it! You’ll love spending all day to saw one log into boards! Best time ever. Seriously though, we need to figure this stuff out and document it. How many kobiki are even still alive in Japan anymore? And just try finding a partner to get on the bottom of your pit saw. Maebiki are the way to go.