How to correct a tapered mortise?

  • Advertise with us

« back to Woodworking Skill Share forum

Forum topic by DavidTTU posted 03-24-2017 03:30 PM 430 views 0 times favorited 4 replies Add to Favorites Watch
View DavidTTU's profile


141 posts in 1806 days

03-24-2017 03:30 PM

Topic tags/keywords: work bench mortise taper

Title says it all. I am working on a workbench that is based on the Benchcrafted “Classic workbench plans”. I cut my mortises using my plunge router, and that part of the process went well. I left a bit too much material because I was afraid of making a mistake with the router. Thought I could clean it up fine with a chisel.

My chisel work was suspect at best. And it took me two mortises to realize it. The last two I was much more careful on, but my first two have a solid taper to them.

What would be your approach to fixing this?

-- -David -- Lubbock, TX

4 replies so far

View Loren's profile


10477 posts in 3818 days

#1 posted 03-24-2017 03:36 PM

Chisel the side of the mortise flat and glue
a thin piece of wood in there. Then, re-trim
using a chisel or the plunge router.

If your chisels are really very sharp trimming
the flat should not be a great deal of trouble.
Use the flat back of the chisel as a sort
of reference surface.

View clin's profile


945 posts in 1166 days

#2 posted 03-24-2017 03:44 PM

I’m not sure it matters, but in what way is it tapered? I assume you took off more than you should have.

In general, you should be able to square it up. Of course the mortise will be larger than planned. If you’ve already cut the tenon, you could glue some material back on the tenon and then cut it to fit.

Since this is a workbench, you might also consider using drawbore pins. These pull the joint very tight at the shoulders of the tenon. The fit of the mortise is not as critical since it is not relying on a glue joint to hold it. In fact a drawbore doesn’t even need to be glued, though I would. Drawbores are also very satisfying to do.

-- Clin

View DavidTTU's profile


141 posts in 1806 days

#3 posted 03-24-2017 03:47 PM

Clin, You are correct. I removed two much material towards the bottom of the mortise. I do plan on drawboring the joint, but I am worried about getting everything square before that happens.

-- -David -- Lubbock, TX

View Ron Aylor's profile

Ron Aylor

2649 posts in 818 days

#4 posted 03-24-2017 03:57 PM

I agree with Loren and Clin both … glue some material to the tenon and perhaps a wedge or two to the inside of the mortise. I am faced with this problem in my current project. As my pieces have moved a bit over the course of the build, I use thin wedges in the mortises or perhaps trim a bit off the tenons to help keep things square!

Have your say...

You must be signed in to reply.

DISCLAIMER: Any posts on LJ are posted by individuals acting in their own right and do not necessarily reflect the views of LJ. LJ will not be held liable for the actions of any user.

Latest Projects | Latest Blog Entries | Latest Forum Topics