Make Square Rabbets – Theory and Practice

I’ve been using rabbet planes for years and I have made my peace with them. However, there are thousands of woodworkers out there who are driven to distraction by these simple and essential planes.

I hope to help you eliminate the two most common errors that lead to rabbets with sloping shoulders and angled cheeks.

Fix Those Shoulders
When you use a rabbet plane, the aim is to make an open trench with a vertical shoulder and a horizontal cheek. Getting the shoulder vertical is the first challenge. Many beginning woodworkers make rabbets with sloped shoulders — the rabbet gets narrower and narrower with every pass.

What causes this? Poor set-up. Actually, strike that. What causes this is a perfect setup.

In a beautiful, sun-drenched, 71° world, you should set the cutter of your rabbet plane so it lines up with the edge of the plane’s body. Makes sense, no? The problem is that this perfect setup tends to give you sloping shoulders. Why? I have a theory.

Keep in mind that this theory was developed to explain reality. So it could be as valid as the theory that the planets revolve around the Earth.

THEORY: If you have the cutter aligned with the edge of the plane’s body, you will make a sloped rabbet because of the springiness of wood fibers. When you press wood down to plane it, you need a clearance angle behind the cutter or the fibers will spring up after being cut and push the cutter out of the cut. Hence, you need some open space behind your cutter.

I suspect this same situation applies to rabbet planes. You cut the shoulder and the fibers are compressed by the side of the plane and the lateral pressure you are applying. When the fibers are sliced, they push back against the plane behind the cutter. Hence, a sloped shoulder.

But if you set the iron so it extends beyond the edge of the rabbet plane by a few thousandths of an inch , then your rabbets are square. This is fact. I suspect that the corner of the iron is slicing the wood and the gap behind the iron is allowing the springback.

Got a better theory?

Make a Horizontal Cheek
When making rabbets, your dominant hand can do you in. It can (and will) tweak the rabbet plane left or right and make a rabbet that either slopes away from or toward the shoulder of the joint.

What to do?

This is an easy fix that I have developed while teaching lots of woodworkers to make rabbets. The goal is to get your dominant hand out of the equation.

Here’s how: Usually you grasp the back of a rabbet plane with your entire hand. Your fingers want to twist the tool. So get your fingers out of the equation. Instead of pushing the tool with your whole hand, push it only with your palm (see the photo at the top of this post).

This change forces you to focus your efforts on pushing the fence of the tool against the work. And this creates a square rabbet. And your dominant hand can do only one job: Push the plane forward.

This really, really works – for me and for students. Give it a try.

The same little trickiness helps with plough planes, too. Just saying.

One Last Tip
Some people have problems balancing the fence of the tool on the edge of the wood, especially when they have made several passes and that edge is getting smaller and smaller with every pass of the plane.

To help keep your tool plumb, align the edge of your board with the front edge of your benchtop. And voila – you have a huge surface to press the rabbet plane’s fence against.

— Christopher Schwarz

Other Handplane Resources
“Handplane Essentials” is my brain dump on this tool. The book is printed in the United States, 312 pages long and filled with information on selection, sharpening, set-up and use. It covers all the planes, except the moulding planes.

We also produced a DVD on bench planes called “Handplane Basics” that focuses on how to use bench planes, the workhorses of the shop. Pick the three bench planes you need and learn how to use them to flatten and smooth boards.