Chopping the Leg Mortises in the Workbench Top.

The time has come to chop the through mortises in my benchtop.  I designed the bench to have double wedged through tenons on the top of each leg.  I realize that this may be a little overkill, but I think that if I can pull it off, it will look great.  There’s no doubt that the joint will be strong.

This is the part of the build that I have been putting off for ages.  I don’t know why, but I seem to have done every other part of the build I can before moving on to this.  I suppose that I spent so long making the benchtop that I have been hesitant to put eight holes through it.  These need to be precise as they will not only be visible in the finished bench, but will actually be a focal point.  I want the mortises to fit tightly and not have gaps around them.

To put the mortises into perspective, I should show you the tenons that are on the tops of the legs:

Here’s an older picture I dug up showing the  double tenons on the top of each leg.

To get started, I carefully laid out the location of the mortises with marking gauges, a square, and a marking knife.  I shaded the areas to be removed with a pencil.

Laying out the leg mortises in the benchtop.

I went around the bench and laid out all of the mortises before I stated to cut any of them. The two marking gauges in the below picture have been locked at this setting since I cut the tenons on the legs.  I just went back into my old posts to find the one where I laid out and cut the leg tenons, it was back in September.  God, I’m slow!!!

I marked out all eight mortises before chopping any.

The benchtop is 4 ½” thick so I’m not about to do this with a chisel and mallet alone.  I will bore out most of the waste wood and clean up the mortises with chisels afterwards. I’ll go about halfway through from the underside, before getting some help to flip the bench top and completing the mortise from the other side.

In my couple of years of rust hunting, I have acquired several braces, but my favorite by far is this Yankee 2101A 10″ brace.  It functions flawlessly and is a joy to use.  That’s good, because boy is it about to get some serious use.

My Yankee brace is about to get a workout.

I bored a series of holes until I was left with this:

This is going to take a while!!!

While boring all these holes my mind started to wander.  I counted and found that it took about 65 revolutions of the brace to get to a depth of about 2 ½”.  There are 14 holes in each mortise (910 revolutions), and eight separate mortises (7,280 Revolutions).  But I won’t be done there… I then have to flip the benchtop and repeat this process from the other side.  It’s a good job that I like this brace, because my math says that I’ll be giving it about 14,560 turns.

After boring, I cleaned up the walls of the mortise with chisels.  I pared a little wood from the walls and then checked them with a square.  I repeated this process until the walls of the mortise were smooth and perfectly square to the surface of the bench.  I paid particular attention to making sure that I did not enlarge the mortise beyond my original layout knife lines.

The walls are cleaned up with a chisel.

I then repeated this process for the other seven mortises.  I estimate that I took me about an hour on average to complete each mortise.  Some days I only had an hour in the shop and managed only a single mortise.  Other days I was able to get two done.  All said, these took most of a week to get done considering the small amount of time I was getting in the shop each day.

I didn’t take pictures of chopping the other seven mortises as all were the same as the first.  After all eight were done the benchtop looked like this:

A long time later… all eight mortises are chopped half way through the benchtop.

I’ll finish the mortises from the other side, but I’ll apply finish to the underside of the bench first.

The benchtop needs to be flipped over to finish the mortises, but I’ll need help to do that. Also, once I turn it right side up, I don’t think that I’ll flipping it ever again.  I will apply a few coats of Watco Danish Oil to this side before I complete the mortises.

I’ll post more about that soon.

– Jonathan White