Best way to round over tenons

[Jared Cuneo]

So I have a nightstand almost ready to assemble, and I used a router to cut the mortises. I left them round on the ends and cut all of my tenons. They all fit great, but now I need to round all of the tenons over.

After rounding a couple over, I am realizing that it might be easier/faster to square up all of the mortises....

Any opinions on quick ways to round the tenons over or should I just square up the mortises?

JC

[Mike Cutler]

A medium flat bastard file will do the work very nicely. Round the edges by filing in an arc opposite the radius you want to achieve. I know it sounds backward, but it's not. A good clean file and it should go a lot faster than squaring up the mortises.
Don't be tempted to use a rasp. They can really tear up some wood in a hurry going across the grain. You should be able to get a Flat bastard file at any Home Depot or Lowes. Nicholson's will be labeled as a Flat bastard file, or possibly a " Mill File". Some of the off brands have their own name. Usually "fine, med, coarse file"

[Tom Slupek]

Either use a chisel or pattern makers file and sand paper

[Alan Schwabacher]

A rasp or cabinetmaker's file can take the corners off to make the tenons fit into the rounded mortises, but they don't really need to match the curve. You want a safe edge to keep from messing up the shoulder.

The easiest way to round the tenons isn't applicable if you've already cut them: it's to cut mortises in both pieces and to use an inserted tenon. You can make long runs of tenon stock and round the edges with a roundover bit before crosscutting. I suppose these days you could even consider buying tenons intended for the domino.

Depending on the design, sometimes you can also get away with simply making the rounded mortises long enough to fit the squared tenons without rounding.

[Jamie Buxton]

If you have through-mortises cut with a router, then it makes sense to round over the tenon. Otherwise, don't bother. What holds the joint together is the glue on the faces of the tenon. That's it. You can square off the edges of the tenon and not change the strength the joint.

[Ken Fitzgerald]

As stated above...it's the glue on the faces that hold the joint. I'd take a handsaw.......cut a slight cut at a 45º angle to both faces at each corner...take a sharp chisel and take off the excess wood. Unless it's a through joint, you'll never notice the difference.

[Jared Cuneo]

Great suggestions! I'll report my findings tomorrow!


JC

[Alan Turner]

Jared,
One tip that might be helpful is to make a pattern of the mortise in a thin piece of sheet stock such as 1/4" mdf or plywood. Use it as a test piece. Then you can sneak up on the correct shape pretty efficiently, without having to mount and dismount the aprons. This might save you a bit of time. You can alao use it to mark out what needs to be removed.

[Jared Cuneo]

Well, I'm a bit disappointed with my results after trying a few methods of making this work.

Actually, the nightstand's dry fit looks great, it's just that I'm not happy with the process of rounding the tenons.

I tried the mill file, cuts very slowly (I'm using ash, so cherry or walnut might be ok), but the chance of catching the side of the file and spoiling the tenon is too high for my liking. I finally used the hand backsaw method of cutting 4 45's on each tenon...what a pain in the butt. This left the joint with too much variation and I'd prefer wood fill that gap rather than air.

I refuse to buy cheap chisels, so my 3 chisel set didn't consist of a 3/8 size....nonetheless, I will definitely be squaring the corners of any future mortises rather than rounding tenons.....

I believe that this will be easier and the resulting joint will be more resistant to racking....

Thanks for all the helpful responses....

JC

[Scott Rollins]

Jared, I agree with you. I have a woodrat and I always use it to cut my mortises. The result is a rounded mortise. With a sharp chisel it only takes about 1 minute to square the corners on a mortise. It takes much longer to round a tenon to fit properly. (this is inviting alot of controversy)

[Tom Henderson2]

A medium flat bastard file will do the work very nicely. Round the edges by filing in an arc opposite the radius you want to achieve. I know it sounds backward, but it's not. A good clean file and it should go a lot faster than squaring up the mortises.


Mike-

Could you elaborate a bit on this? I'm not sure I follow what you mean by "filing an arc opposite the radius you want to achieve."

Thanks! I'm a newb, with lots to learn.

-TH

[Bruce Pennell]

Jared if you have a router table a bead bit or round over bit works great. Cut your tenon stock to width, round over, then cut to size. Fast and easy.

[Mike Gabbay]

If you want the tenons to look traditional (hand cut) then square off the mortises and keep your tenons square. Otherwise the safest way for me is to use a bastard file and sand paper. It may take time but it is better to go slow and sneak up on a good fit then to rush through it. Also as Alan memntioned, use a test block for the mortise that is the same size on your finished peice.

M&Ts can require fine tuning especially through tenons since it is harder to hide your mistakes. If you want the through tenon to look really good it just takes time and practice.

[Jesse Cloud]

Couple of tricks:

You can get a good start with a roundover bit on a router table - won't go all the way to the shoulder, but still saves lots of time.

Make a few scratch sticks from an old bandsaw blade or other scrap steel. If your tenon is 3/8, drill a 3/8 hole and snip it in half, that gives you two round scrapers. Sharpen them with a file if you like.

Make sanding sticks from scrap sticks of wood. Put them edge to edge up to the width of a sheet of paper, spray on adhesive, put a sheet of paper on it. Then cut them apart with a utility knife. Lots of control with these guys and you can sneak up on a perfect fit.

[Aaron Beaver]

I just use loose tenons, mortise both pieces. Then run the tenon stock through a round over bit on the router table and I am all done.

[lowell holmes]

Kelley Mehler shows a trick. Take a piece of a sanding belt and use it like a shoe shine rag to put the round on the tenons. You can round the edges in less time than it takes to talk about it.
I've begun to square the mortices though with a small sharp chisel.

[Matt Day]

Or if you have a powered sanding belt or disc (or even one mounted to a DP) you could use that.

I would think starting with a round over bit on the router table would be the best sure fire way to get the right profile for a majority of it, then hitting the rest with a power sander would finish it off. I personally don't like squaring mortises with chisels, probably because my last project I did this I had a few dozen to do. Now I have a bench top mortiser though:cool: