One of the most frustrating parts of using a smooth plane is when you have a low spot on your board that simply refuses to be planed out. There are several strategies. Here are just a few:
- Just keep planing as usual until you are an old man or woman.
- Drop down to a coarser plane (such as the jointer). But this could introduce tear-out.
- Increase the depth of cut. This could introduce plane tracks.
- Put a shaving under the low spot between the board and the benchtop. This works only sometimes.
- Change your frequency, Kenneth.
What I mean by “frequency” is how closely spaced each pass with your plane is to your previous pass. Some drawings might help explain this better than words.
So here’s a panel that I’m planing with my No. 3, which has an iron that is 1-3/4” wide. When I begin to plane the board, I’ll stagger each pass about 1-1/2” from my last pass to ensure every bit of the panel gets to see the plane iron. In the drawing, each line on the panel represents the center of my plane’s iron.
After I plane the panel a couple times, I might notice there’s a low spot in the middle, which is very typical.
What beginners do is try to plane the low spot to remove it. This doesn’t really do anything (unless you switch to a much shorter plane) because it’s the wood that surrounds the low spot that is preventing the plane from cutting the low spot.
So here’s what I do. Instead of staggering each pass of the plane 1-1/2” inches from the previous, I’ll stagger it 1/2” or 3/8” as I get close to the low spot. Changing up the spacing of your passes will help remove high spots left by previous passes and allow you to access the low spot faster.
Yes, this can introduce a shallow cupping on the face of the board, but it is insignificant in my experience. A machine planer and sander will leave a surface that is more irregular that the approach described above (and is still a surface that is perfectly flat enough).
— Christopher Schwarz
Shameless plug: For more handplane tricks, check out my book “Handplane Essentials Revised Edition,” which is a massive brain dump on these essential tools.