Another Wedge Tenon Question

Mike Gabbay

Member
Messages
180
Location
Herndon VA
I'm still working on the base of my bench.... :eek:

I'm using wedged tenons and have cut the kerfs to be around 6 - 7 degrees. For the top of the legs/trestle M&T the mortises have been cut back about 1/8" - 3/16". It looks like using a wedge that is 6 degrees may not spread the tenon enough. How many degrees should the wedges be? Same to match the kerf?

Thanks, Mike
 
Alan - After I posted the question I realized the answer....
For some reason I'm having a hard time getting a consistent angle on the kerf cuts using the bandsaw and the wedges. I even used a jig....:dunno:

Thankfully, the pieces I've cut so far are for the leg/trestle M&T so they will be covered by the top. I'll try more test cuts before I do the stretchers.

One other method I was reading about last night was to cut a straight kerf about 1/8" from the edge and then use a half wedge (angle on one side that matches the mortise angle). Seems simpler.
 
Mike,
To make accurate wedges for wedged tenons, lay out the wedge on the edge of a piece of scrap of sufficient thickness using a draft angle table or protractor. Then simply hand saw and carve a notch for the wedge you have marked. Pare to the line with a chisel.

Run a piece of ply through the bandsaw part way using the fence, and this is your new BS table. It is tight to the blade, of course. With this aux. table, you will not have the wedges falling into the opening. Now cut your wedge holder to the same width off the BS fence (backwards), and then turn it over, and you have the perfect wedge jig. Put your end grain blank into the carved recess, and slice away, flipping the blank each pass. It does not take long to make the jig, or to cut 100 accurate wedges.

I reread your first post, and realized that you may have an issue with the mortise. It is the mortise which is angled, not the kerf in the tenon. The tenon is simply kerfed. The mortise is full width at the entrance side, and relieved on the other side, to a determined angle. 5 degrees is pretty common.
 
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Alan - let me see if I get this right. Basically the jig for the wedges is a push block with an angled side. Kind of like a fixed tapering jig?

I have made a similar jig. My wedges are 5 degrees. So I cut a piece of ply with a 5 degree angle. I glued that to a piece of 1/4 ply that is around 24" long and 8" wide. I place the stretcher on that and then cut one side of the kerf. Then with a similar jig with the opposite angle block I cut the other side. That seemed to work well last night when I switched to a 1" blade on the BS. Earlier I was using a 1/2" blade and the cuts were not as nice.

I was going to use the same set of jigs to cut my wedges.

Now I have another question about dowels... I start a new thread.
 
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