Making a moulding plane: Step 4 – Boring (the Wedge Mortise)

This is the fourth part in a series on making a moulding plane.  If you haven’t been following along, check out the previous posts using the following links:  Making a moulding plan: Step 1 – The blankMaking a moulding plane: Step 2 – Layout, and Making a moulding plane: Step 3 – Making the grip and escapement.

In this post, I’ll show you how the wedge mortise is bored and how the mortise and escapement are finished.  At the end of the last post, we had sawed out the escapement and removed the waste material with a chisel.  Now it’s time to complete the wedge mortise and escapement.  We’ll start by securing the plane body upright and getting an 1/8″ drill bit chucked up.  We will need to bore two holes, one about 1/8″ from the front of the mortise and the other about 1/8″ from the back of the mortise.  Choose which one you want to bore first and secure the plane body in a vise so that the when you bore straight down, the hole will be leaning slightly toward the inside of the escapement.  In other words, if you are boring the hole closest to the front, position the blank so that the front of the escapement (the breast) is just off of vertical and leaning back toward the heel of the plane blank.  If your boring the hole on the bed side of the mortise, you want the bed side of the escapement nearly vertical and leaning slightly toward the toe of the blank.  If this doesn’t make sense, leave me a comment and I’ll post something graphical to clarify.  You will also want to lean your boring tool slightly so that the hole runs toward the escapement side of the plane instead of straight up and down.  More on that later. . .

I used a gimlet bit in my brace, but you can use pretty much any set up you have available.


If you use an electric drill, set it to run as slow as you can.  You want to be able to control the direction and depth of the hole as much as possible. One advantage to using a gimlet bit is that the bit can be steered more easily than a brad-point bit while the hole is getting started.  You might be able to get a similar level of control with an 1/8″ machinist drill bit as well – just make sure to use an awl or punch to make indentations for the start of the hole.

Bore these holes slowly and back the bit out every few turns.  The bits won’t be able to clear chips out of the hole and will tend to get very hot which can ruin the bit.  It’s wise to place the bit on the outside of the plane along the grip so you can use some type of depth indicator or stop on the bit.  You will want the bit to just clear the top of the escapement and then stop.  A piece of blue painter’s tape works well as a depth indicator.  Just tear off a piece and put it around the bit like a little flag.  When the taped off section gets to the top of the mortise, you’re at your depth and can stop drilling.

The two holes will (hopefully) meet somewhere around the top of the escapement.   You want to see the bit pop out at the top of the escapement about 1/16″ into the plane body from the ramp area you left under the shoulder.  I didn’t lean my brace far enough toward the escapement side of the plane when I bored my holes and ended up not being able to even see the tip of the bit.  You can see half of the holes left by my bit in the photo below. This wasn’t ideal, but it doesn’t ruin the plane either.


Once the holes are bored, use a 1/10″ chisel to start prying out the material between the two holes through the top of the mortise.  This can take a little time, but all you are trying to do at this point is open up the mortise so you can get an edge float into the mortise.


When the mortise is open enough, start using an edge float to widen the mortise almost to the layout lines (leave a little extra for fine-tuning the mouth).


It shouldn’t take very much time with the edge float to have the mortise opened up to close to it’s full length.  Next, it’s time to widen the mortise with a side float.  The side float is the tool you’ll use to make sure the side walls of the mortise line up properly with the blind side of the escapement and that the bottom of the mortise at the top of the escapement is exactly the same width as your wedge (3/16″ in the case of a #6 plane).  Use lighter and lighter touches with the float as you get close to your desired size for the opening.  Floats are extremely dynamic tools.  They can take very heavy cuts if the handle is lifted and firm pressure is exerted, or they can make extremely fine controlled cuts if used flat and with a delicate touch.


At this point, we have opened up the mortise.  In the next post, I’ll show how to bed the iron and fit the wedge.

Until next time. . .

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