Rounding Tenons

Thoughts on rounding over the corners of tenons to fit into bored mortises. November 11, 2008

I'm making a small batch of side tables for a client and for reasons that relate to the design I've mortised the legs with a router. This leaves me with the problem of rounding over a batch of tenons to fit the rounded slots of the mortise. Is there a method of rounding the tenons apart from by hand? They are not loose tenons.

Forum Responses
(Furniture Making Forum)
From contributor P:
There are several router jigs you can buy or make to do that, and cut the tenons too. The JDS is what I'm going to buy but the Leigh is nice too. Personally, a good rasp and file are what I use now and I can fit a tenon in a couple of minutes.

From contributor W:
I am a rasp and shoulder plane fan myself. For anything less than a couple of dozen tenons hand rounding is cost effective. Now if this design or variations on it is going to be a staple of your work, then jigging up is viable.

I held off getting a dedicated mortiser until I started getting orders for dining room chair sets and multiple rocker orders. Then I went with machine mortises, cutting the tenons on the bandsaw and light fitting by hand.

From contributor K:
I agree with Contributor W and P. You'll be surprised how fast you can round those things off. If I have more than that – I recently had a run of 120 – then I rip tenon corners off on the bandsaw. Set the bandsaw table at 45, set up a depth stop and away you go. A quick swipe with a handsaw or chisel or file to clean up if you need to. Some folks worry about the space left by 45ing those edges, but I don’t – it’s mostly end grain in the round, anyway, and doesn’t help you with gluing surface. If you aren't using glue, (knock down scenarios, for instance) that's a different story, but then I'd chop my mortices by hand.

From contributor R:
You don't have to round them. I've been doing it for 30 years, or not doing it.