Workbench Tenon
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Hello all,
I’m in the process of finally building my own workbench.
While building the legs and rails section of the bench I made a mistake on one of my rail tenons.I mixed up the bottom and top rail while sawing of one of the haunches.
Luckily I noticed before doing the same on the other side but now I’m left with a tenon thats to small for the mortise hole.To fix the problem I was planning on glueing a piece of wood back in place.
However I’m having my doubts if this would still be strong enough.
Since the woodfibers have been crosscut it seems to me this would cause a weakness in the joint.Did anyone else run into this problem and if so how did you fix it?
Kind regards,
Joost
P.S. see attached picture if its not clear what I mean.
hello Joost
i built this bench also.
from the looks of your picture it appeara that the tenon is not tall enough but probably fits well otherwise
i dont think that you would be overly compromised by gluing a piece in place to fill in the gap.
i supposed that the end grain to end grain glue joint is your primary concern?
if you want to mitigate that concern, you could mortice into that end grain and insert a tenon that is then able to bond more securely?just my opinion
but i hope this helpscongrats on ur new bench
i love mine
rog
its just my opinion
Your correct that the tenon isnt tall enough thats where the whoopsie happend.
The end grain joint is indeed my concern, the left over tenon is about 115mm.
Considering that the toprail has the same dimension I figured it wouldnt be a big problem just looking for other viewpoints.The extra tenon idea is something I hadn’t tought about. I’ll see if I can make that work, the cut away part is only 25mm so that could be a challenge.
Thanks Rog.
I wouldn’t worry about it too much. I would probably make a slightly tapered insert and tap it in when gluing up.
Paul.
Hello Joost,
The strength of a tenon and mortice joint to a significant degree depends on a snug fit of the shoulders – assuming there are shoulders, of course, But if so, then perhaps drawboring is an alternative that will help with both tight fitness and the lack of support for the upper end of the tenon. 3/8″ dowel bars appear to be quite readily available, and they also do away with the need for clamps.
If you glue a scab piece of wood to make up the missing width, I believe you can have confidence in the result.
As Sven-Olof mentioned, some of the strength comes from the tenon pressing against the walls of the mortise. In a perfect joint, the mortise mechanically (without glue) keeps the tenon from rotating within the mortise. Really, some of the strength comes from the fibers in the rail running continuously into the tenon. In your case, you will not have this for the portion where you glue on the scab. On another piece, like the small tenons in a grandfather clock door, this would matter. On this bench, though, the tenon is so wide that even the reduced-width tenon will have plenty of strength. So, even though the scab is glued to the tenon, the scab is really changing the size of the mortise to give the smaller tenon something to lever against. At least, that’s the way it seems to me.
I am not sure it is even necessary but I would do like Paul Rowell said.
The glueing surface is great enough to keep the pieces together and if the shoulders have a good fit, they will care for the geometry of the assembly.
Thank you all for the advice.
I decided to glue a pice back on the tenon.Hope I can finally finish cutting the last leg so I can start glue up.
Glued up the leg frames today.
The fix felt sturdy and you cant see it anymore.
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