If you can sharpen a chisel, you can sharpen a plane iron. But there’s one key difference that makes sharpening plane irons a lot easier.
On chisels, the back needs to be flat right up to the cutting edge to cut accurately.
But on plane irons, the back only needs to meet the opposite bevel at the very tip of the blade.
And thus, The Ruler Trick was born — credited to the late great David Charlesworth.
The ruler trick saves you literal hours trying to lap the back flat, meaning you can get back to using the plane ASAP.
Here’s how it works:
- Take one of those super thin metal rulers and set it along an edge of your sharpening stone. Any very thin piece of metal works (I’ll use an old Dozuki saw blade sometimes).
- Set the plane iron onto the ruler, then gently set the tip down so it rests as close to the opposite edge as possible. The bevel of the blade should be facing up.
- Slide the blade back and forth sideways, keeping even pressure on the tip. Keep the cutting edge no further than ¼” from the edge for the entire operation.
- Once you can feel a burr along the entire beveled edge, you can move on to the rest of the sharpening process.
The key is to lightly hit only the very tip of the blade. In essence, you’re adding a super tiny back bevel — but don’t overdo it.
Use this trick for lapping the back initially and also removing a burr after honing the bevel on the other side. It's not necessary for stropping.
And remember: Don’t use the Ruler Trick on chisels!
Looking for an inexpensive way to learn hand tool sharpening? Then check out the Scary Sharp System.
This method of sharpening uses a specialty 3M microfinishing sandpaper instead of traditional stones — making it ridiculously affordable.
Simply mount the paper onto a flat surface (each sheet has an adhesive backing) and sharpen away.
The coolest part is the equivalent grits of the sheets go all the way from 300 (good for establishing a bevel) to 60,000 (essentially a super fine strop).
This is THE place to start if you’re new to sharpening.