Tightening Loose Tenons
George VondriskaDescription
If you’ve got a shop, you can pretty much guarantee that people will ask you to repair their furniture. It just comes with the territory. The next time a piece comes into your shop with loose, round tenons, try this easy repair method to tighten them up by adding a simple shim.
Add more glue, right?
Wrong. Some people would look at a repair like this and try to fix it simply by adding more glue to the joint. Sorry, but that ain’t gonna work. The piece will be coming back to your shop for another repair before you know it. Standard yellow glue can only fill tiny gaps; nothing larger than a few thousandths of an inch. Paper is about .003”. If the gap in the joint is more than that, yellow glue won’t work long term. Instead, you’ve got to build out the loose tenon to create a better fit, which will allow the glue to do its job.
Round vs. Rectangular Tenons
Tenons that are square or rectangular are relatively easy to fix. Just glue on a piece of veneer, sand, chisel, or plane the veneer to get the fit you want, and you’re ready to go. Round tenons are a different story. The technique shown here allows you to create a loose tenon wrap that will create the perfect fit.
What is a good fit?
How do you know when you’ve got the tenon right? You should be able to slip it into the mortise with hand pressure, not requiring a mallet. When you gently pull on the parts, friction in the joint should keep them together. They shouldn’t just fall apart.
More on Tenons
Creating tenons from scratch? We’ve got some indispensable tips, including this quick rule for tenon joinery.
So a friend of mine dropped this baby off a couple of weeks ago asking if I could fix it. So I'm working on it, and I think it'll come together. It's gonna take some time and some patience. But see, I'm seeing if that rail that rung is gonna come out, I don't think so. One of the things I'm doing is, going over all the rungs and getting the glue residue off. That's a really important step. We wanna get rid of all of that kind of stuff. Now here's the thing. I'm gonna put this back together with conventional yellow glue. And in order for yellow glue to have a bond, we really need to have a good fit between the mating components. And lemme show you where this is problematic. That glue came off nice and easy. Now, I wanna look inside the hole as well and get any glue residue out of there. This one I've already taken care of. And this is the problem I wanna show you. When I put that rung in, look at how loosey-goosey that is. So, I can put a half a gallon of yellow glue in there, and I'm not gonna do my friend any favors putting this thing back together, because we're just not gonna have a good glue joint there. So here's a solution when you're working with round rungs like this. This is pretty cool. Here's what I'm gonna do. I've got a piece of maple in a vice here, and I wanna use something that's close-grained and straight-grained. So maple would be good, poplar, cherry, red oak wouldn't be a great choice for what we're about to do. I've got a block plane set at a real light depth of cut, a jack plane or something would be fine if I owned a jack plane. But the block plane is gonna do okay. And let's get a couple curls coming off of here. And then we'll find a good one. All right. Oh, there's a beaut. What did I just make here? I made wooden filler tape. So the way that this repair is gonna happen is, I'm gonna end up taking these ends, applying some glue to 'em, and wrapping this shaving around in order did it increase the diameter of that end. Once I get to the end of the shaving, I can tape that in place, allow the glue to dry, take the excess off the end, and then test the fit again. What that'll do is probably leave me a tiny bit oversized, so I'll do a little bit of hand sanding and I'll tweak each one until I get a perfect fit. So I think this adding veneer, adding a curl off your plane like this is a pretty cool solution to allow you to build this round stock back up to where it needs to be in order to get a nice, tight fit between the rung and the hole it has to fit into so that this chair is gonna last another few decades for my friend.
Once the glue on the tenon and in mortise are removed, why not just use epoxy which is a gap filling glue?
Will be using this one, thanks.
That is a new way I had not seen before. I will have to try it. I have split the tenon's and put wedges in to spread them. The last time I used CA glue without disassembling the joints. Both methods seem to work too.
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Thanks very much for this tip. I have a couple of nice oak chairs that unfortunately are used on a carpeted floor so the rungs are continually coming loose. This looks like it may be the solution.