Round tennons or square mortices

[Jim Young]

Today while rounding off my tennons to fit the router cut mortices my arms got tired. I wondered how many people do it this way and how many square out the mortices. What are the advantages either way.

Second question, If you round your tennons how do you do it? I used a file and it went fairly slow.

The more of this type of woodworking I do the more I appreciate those true craftsmen.

TIA

[Bob Lasley]

Jim,

I round the tenons with a fine rasp. Seems easier than chiseling mortises square. That said, I don't make too many router cut mortises since I got the mortising machine.

Bob

[Doug Edwards]

I will square the mortices. I can cut a straight line easier than a curve and it lets me use my very sharp chisels. I find that I can get a better fit using a chisel than filing, rasping or routing the curves.

[Don Henthorn Smithville, TX]

I use a rasp to do fixed tenons but I use roundover bits in the router table for floating tenon material. This is fast and as accurate as squaring the mortises.

[Dennis Peacock]

Jim,

How about trying "floating tenons"....This will be a lot easier and faster and just as good and still allow you to make your mortises with the router. Works good and holds just as well.

[Chris Knight]

As other have said, loose tenons are easy and strong - they also save wood - tenons can be made from scrap and you only cut your stuff to the length between shoulders.

If determined to round your tenons - try just chiselling a chamfer on each corner of the tenon - it leaves a gap in the mortise but the important long grain on the tenon cheeks is not reduced by any practical amount and the glue joint is fine. The gaps also give the glue somewhere to go so your fit can be made tighter with worrying about piston effect.

Chris.

[David Rose]

tennons. But if you peg a tennon in case of glue failure or whatever, then you should peg the tennon going into the rail or whatever is tennoned also. I don't know how realistic glue failure fears are. I think this comes from the fact that really nothing but hide glue has been tested for serious longevity. I know we live in a disposable age and what I produce will likely be laughed at by my heirs, but... If something I build is desirable to anyone, I would like to see it still holding up lots of years from now.

I've rounded tennons with files. I've rounded them with a keen chisel. I've cut the mortises square with a chisel. Only a few dozen with each method. I like the fit of squaring the holes, but it takes me longer.

All these methods take more time than I like. I am looking hard at trying to fit the FMT by Leigh into the budget. It's an expensive tool for me, but I see lots more tennons in the future. If I counted my woodworking time as money, I would get one now.

David

[Kirk (KC) Constable]

You get more glue surface when you square off the mortise, which in theory will mean the joint should be stronger. I've done both ways, and whichever way is easier for the specific task is the way I go now.

KC

[Bart Goldberg]

Jim, You can't just use any file - to be able to round out your tennons easily, you must use a nicholson #49 or #50. Other files will take forever. The nicholsons will power though this taks like the wood was made of butter. This was a tip I picked up at a seminar from Mark Adams at last years wood working show.

[Ken Salisbury]

The strength of the glue joint in a mortise/tenon operation is on the sides. I made many, many round mortises with my horizontal router table before buying a mortise machine. If the tenon used overlaps (as shown in the pic) then there really is no need to round off the tenon. Just make the width as shown so it fits the mortise. I just don't see the need for another operation like rounding over. If it is a through mortise then this approach would not apply."Keep it simple"

Just an old man's 2 ¢ worth

<p align="center">
<IMG src="http://www.klsal.com/roundmortise.gif">