# Best technique to round over tenons?



## Picklehead (Feb 12, 2013)

I'm doing my first mortise and tenon piece, and I'm wondering what different techniques people use to round over tenons when making mortises with a router (1/4 inch in this case). My thought was to use a flush cut saw to cut a kerf at the shoulder of the tenon then use a chisel to split/shave off a 45 degree chamfer, starting at the end of the tenon and working towards the shoulder. That seemed to work in my pine test pieces, however on one piece I actually removed too much and narrowed the tenon a bit, which would allow it slip within the length of the mortise a little. I know I could do floating tenons, and I may in the future. My main concern is to avoid damaging the shoulder or face of the workpiece, so if I rasp it or something else how do I avoid that? Before I go reinventing the wheel and cutting kerfs in the shoulder of the tenon and sticking in thin protective pieces of cardboard, I figured I'd ask the people who know. (Or maybe I should be squaring the mortises by hand). Thanks for any advice.


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## JustJoe (Oct 26, 2012)

I just use a corner chisel to square the mortises, but if you don't want to do that then just a few swipes with a decent rasp will round the tenons.


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## nwbusa (Feb 21, 2012)

Yeah, I also square out the mortise corners with a chisel. But I agree with JustJoe, if you want to round off the tenons, a rasp will do the trick.


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## theoldfart (Sep 9, 2011)

I'm going to echo Joe and John, use a mortise chisel to square the ends. Use a chisel the same width as your mortise and the chisel will follow the sides all the way down without twisting giving you a square end. I do this all the time except I hand drill to remove the waste, but the concept is the same. Good luck.


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## Picklehead (Feb 12, 2013)

Thanks for the info. Guess I'll make up some test pieces and see if I can rasp them properly.


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## bondogaposis (Dec 18, 2011)

I'm one who'd much rather round a tenon that square a mortise. I use a chisel for the most part paring away a little off the corners at a time. I use a rasp too but you've got to be very careful that you don't gouge the shoulders just keep the rasp away from the shoulder and finish up w/ chisel.


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## Picklehead (Feb 12, 2013)

Thanks, Bondo. That sounds like a good mix of techniques. I'm leery of mucking up the shoulder, which would be visible on the finished face of the tenon board.


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## MJCD (Nov 28, 2011)

For something completely different…

I mount the tenon in a clamp, use a coin to create a half-moon tracing; use a razor knife to take off the bulk material, then sandpaper pulled down and back & forth to smooth the rough edges into a half-moon: works every time.


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## MAKZ06 (Jun 17, 2013)

I always used a round over bit in my router table and get as close to the shoulder as I can. Then a sharp chisel run down the face of the tenon to the shoulder easily takes off the last little bit you can't hit with the router bit.


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## 111 (Sep 2, 2013)

Cut the tenon 1/8" short, (the shoulder an 1/8" long) rasp the corners then cut off another 1/8" of the shoulder getting rid of any damage that may have happened from the rasp. Then just have to chisel the little saw cut left.
Just a thought, I've never actually done it.


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