rounding a tenon

[Bill Conerly]

A while back there was a thread round the tenon or square the mortise (https://www.sawmillcreek.org/showthread.php?34601-Round-the-tenon-or-square-the-mortise)? Opinions were mixed. I know how to square a router-made mortise with a chisel, but I'm not sure the best way to round a tenon cut on a table saw. (I am not looking for a totally round tenon like on a chair leg; just a rectangular tenon with rounded ends to fit into a round mortise.)

Hand file and sandpaper? I can imagine using a roundover bit, but I don't have a router table I think it would be tough with a handheld router.

thanks.

[Denis Kenzior]

I generally do this with a chisel and a file. Pare away the corners to remove most of the waste then round off with a file. Don't file too close to the shoulder, it is too easy to mess up the shoulder if you're not careful. Near the shoulder I rely on the chisel only. If the tenon is hidden it doesn't need to look pretty, just fit!

[Bryan Lisowski]

A chisel is the way I have done it, then finesse with sandpaper.

[Prashun Patel]

I use a handplane for a loose tenon or a rasp for an integral tenon.

In fact, if the tenon is long enough, you can rive off the corners straight down with a chisel to effectively chamfer the edges enough to mostly clear the roundover.

[lowell holmes]

If you can saw 8 sides to the tenon, rounding the tenon is easy. Practice on scrap wood.
It can be done with sharp chisel.

[Dave Zellers]

If the tenon is long, say an inch and a half, I always start with a round over bit with a radius that matches the radius of the straight bit used to make the mortise. Either by hand or on the router table I round over the edges stopping short of the shoulder. At that point it is really easy to finish with a chisel. Pare toward the shoulder with the chisel held flat on the round over rotating a bit with each stroke. With a sharp chisel it will perfectly transfer the round over up to the shoulder. I know it will never be seen again but it's fun to do.

If the tenon is short I would square the mortise.

Edit- I see that you don't have a router table. Just use a piece of stock the same thickness along side the tenoned piece for extra support.

[tom lucas]

If you have one, and it can be chucked up - a lathe.

[Ted Derryberry]

Cut it round to start with using a PantoRouter.

[Alan Schwabacher]

The simplest method is to neither square the mortise nor round the tenon, but to make the tenon a little narrower so it fits while leaving half-round gaps at each end. For many purposes this is plenty strong.

[Robert Cherry]

I prefer to keep it simple and round them with a float. Mine has a safe edge so the shoulder does not get messed up.

[Charles Lent]

Why round the ends? Make your square end tenon the length of the flat sides of the mortise and leave the half round ends of the mortise empty. The sides of the tenon/mortise glue joint are where the strength is, and the half rounds will allow a place for the excess glue to go. Although I now have an FMT Pro jig for my mortise and tenon work, I made round end mortises and square end tenons for years, way before the FMT arrived and never had a M/T failure. I bought the FMT when faced with a job that would require over 1,600 M&T joints and it paid for itself with that one job in time savings alone. If I hadn't done that job I would likely still be making round mortises with a router and square tenons on the table saw to fit them.

Charley

[Ellen Benkin]

First question -- is this tenon visible? If not -- who cares how you do it and if you butcher it. If it is visible, I would use a file and then smooth it with sandpaper. But this is exactly why I prefer "floating" tenons. I can make a long piece of scrap wood rectangular to fit the mortises and round over the edges with a router.