The architect on this particular job, is interested in the option of doing square Japanese style peg holes. I'm just wondering if anyone has any suggestions on the best way to do it. I could drill a 1" hole and chisel it out with a corner chisel. I looked at large stationary mortisers, but they don't have enough stroke or flexibility. What I wish existed would be a chain mortiser style machine with the capacity to take a 1" mortise chisel auger to cut through 8" of white oak. And while I'm wishing I'd like a pony and a million bucks for Christmas.
Any ideas?

Well if you get a pony get one that bucks you will be half there.

Depending on the size of the project, can you get someone to make a new bar for a chain mortiser? Or is one inch too tight for the chain? Can you use rectangular pegs so the mortiser works? I've seen 7/8" mortice bits but I have no experience with them. The bit was 4-5" long can it be welded so it can be extended into the piece?

The hole only needs to be square at the surface. Bore a regular hole and then square up the first inch into the timber with the corner chisel as you have mentioned.

Then when you put in a round peg with a square end the peg will appear to be square. You'll have to draw knife your own pegs to make the work.

Does that work for you?

Jim Rogers

What about if you can view both sides of the timber? Alas seeing both sides of the peg?

Didn't makita used to make a hollow mortiser for timber?


I'd make some samples first for the architect, then price out how you'll do it.
Cheaper way is to peg with standard pegs and use square plugs inserted from both sides.
Expensive way is to cut them all by hand.
Perhaps slightly less expensive way is to buy a woodworking mortiser and modify the base and cut from both sides. Clean up by hand.

It seems of you use a draw bore that your blocks will need to be extra long with some taper to them so you can drive them in.

Hello,

Just trying to imagine squaring up the peg holes in an entire frame because I have not done it on that scale all in one go and so my reaction, based on what I have done is that squaring up the holes is not really a big deal and even doing them by the hundreds doesn't seem like it would be so bad, and in oak would go quite well. It really comes down to a personal judgement.
On a practical level I have noticed holes being squared by taking the chisel from a mortice boring machine in the hand and using it with a hammer to square up round holes. There are some disturbing aspects of that idea that maybe could be worked out though. Also remember that Japanese pegs holes are not drawn, just straight, so draw boring with a square peg, while I've done it, is an incongruity in the strictest sense, (think about deflection of the peg for one thing), for what that's worth.

Greetings,

Don Wagstaff

Thanks for all the input...I think I'll try a couple methods and see what works.
One thought I initially had for draw boring would be to insert wedges from both sides. Like one would in a wedged scarf. That way the peg hole would be filled on both sides. That would weaken the pin too much though if it was only 1" x 1". I would probably have to make it rectangular to avoid failure of those wedges. Or just not draw bore them and use one square piece.

Don, what do you mean by disturbing aspects of using the chisel from a mortise boring machine. Other than otherwise reputable timber framers whacking a chisel with their nail hammers ! I agree that it probably isn't going to too hard even with a corner chisel. Just out of curiosity, what was your application for square pegs?

Hello,


It's just that the chisel's obviously not designed to be used with a hammer and it should be properly adapted.

I last used pegging like this in the half-lap jointing of roof trusses. I can't really speak of draw boring in that case, but the holes in both halves were off-set so driving the pegs did tension the joint.

That idea of driving 2 wedged pegs from opposite sides is feasible enough. I hope you pass on how goes if you try.

Greetings,

Don Wagstaff

I'm not sure where you get the idea that draw boring isn't done in Japanese carpentry Don.

What do you make of this then?:

[img:center]https://picasaweb.google.com/104943063435486564254/December62012#5818993359399316450[/img]

Chris,
I couldn't get that link to work...Could you repost? I'd like to see it.
I'm currently leaning toward doing a solid square peg and just offsetting the holes a bit. Interesting ideas all around.
Does anyone know where I could find information on portable hollow chisel mortisers. Info seems scarce and Makita USA can't even get info on products for other markets.