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Wedged Tenon Advice
Posted: Mon Jun 30, 2014 2:39 pm
by forrestb
My second attempt at using a wedged thru-tenon did not work out well::eek:
[ATTACH]25505[/ATTACH]
I found advice on doing these several places on the web. One in particular said to always drill a hole at the end of the cut for the wedge to prevent the crack going up the wood (see above). Others said that they never do so and have had no problems.
My advice is to always drill a hole, dummy!:mad:
Actually, the advice was to drill an oversize hole first and then saw down to the hole.
I will now try to find the end of this crack and drill a hole to prevent it from propagating any further. Ruined an otherwise very nice piece.
Oh well, I remember a shooting instructor saying don't worry about mistakes because you can always serve as a bad example to others.
Forrest
Posted: Mon Jun 30, 2014 5:03 pm
by idcook
forrestb wrote:
Oh well, I remember a shooting instructor saying
don't worry about mistakes because you can always serve as a bad example to others.
Forrest
This will come in quite handy.
Thanks Forrest

Posted: Mon Jun 30, 2014 7:59 pm
by charlese
At least you can laugh at the attempt.
You'll have to explain a wedged thru-tenon to me. I know a thru-tenon. Have made several. Do you first make the thru hole and the tenon, then wedge the tenon?
I see the split in your piece, but don't see where the tenon would slide thru.
Hope this helps
Posted: Mon Jun 30, 2014 10:41 pm
by forrestb
A wedged thru-tenon is most like a thru tenon except the mortise is angled so that wedges driven in saw cuts on the tenon force the side out. Kind of like a dovetail:
[ATTACH]25511[/ATTACH]
I have sectioned the mortise to show the angle. The wedges force the tenon outsides up against the angled mortise sides. It is a strong joint that does not even need glue - try pulling a dovetail apart at the 90 degree angle from which it was installed. Just remember to alternately tap in the wedges so they are driven in evenly,
A reference without good pics is
http://www.woodworkdetails.com/knowledg ... -and-tenon
Forrest
Posted: Tue Jul 01, 2014 1:38 am
by rcplaneguy
Any chance you could rout/drill/chisel the wedge out and glue the crack closed? Then make a passive wedge patch? I've used the small Dremel router attachment to do tiny repairs.

Posted: Tue Jul 01, 2014 3:31 am
by skou
I've always thought a wedged tenon, was a knock-down mortise and tenon, something like what I'm (going go try) to attach.
Couldn't attach it. Dang.
You know the one, tenon goes through the mortise, and has a square hole in the outside end, and a wedge gets put in that hole. Tap down on the wedge, and pull the joint together. Tap the wedge out, and you can disassemble the joint.
http://www.diynetwork.com/how-to/how-to ... index.html
This one. (Got it.)
steve
Posted: Tue Jul 01, 2014 3:32 am
by skou
Posted: Tue Jul 01, 2014 7:13 am
by JPG
skou wrote:I've always thought a wedged tenon, was a knock-down mortise and tenon, something like what I'm (going go try) to attach.
Couldn't attach it. Dang.
You know the one, tenon goes through the mortise, and has a square hole in the outside end, and a wedge gets put in that hole. Tap down on the wedge, and pull the joint together. Tap the wedge out, and you can disassemble the joint.
http://www.diynetwork.com/how-to/how-to-make-a-wedged-tenon-joint/index.html
This one. (Got it.)
steve
That was what I was originally thinking. The split did not make much sense then. If anything, I would expect the
end to split out.
So glad for the pix to explain all.
Y'all know about the blind version of that wedged 'joint'?
I wouldn't even try!
Posted: Tue Jul 01, 2014 10:07 am
by forrestb
JPG, if you are referring to the fox wedged tenon, I will pass! I obviously have enough trouble when I can see things.
http://sawdustmaking.com/woodjoints/mor ... n.htm#f158 talks about that in Fig. 158.
Forrest
Posted: Tue Jul 01, 2014 11:16 am
by Ed in Tampa
I suspect the tendon was too loose in the mortise in the shoulder area. Then when you drove the wedges in the wood instead of being contained by the tight fit was able to expand and cause the split.
If you can get the joint apart glue the split close then before reassembling using shavings build up the shoulder of the tendon so it is tight fit into the mortise. Then drive your wedges in.
Depending on how much clearance there was between the mortise and shoulder of the tendon drilling holes at the end of the wedge splits may not have prevented this.