How to Adjust the Tightness of Your Japanese Hand Plane
Riho Egawa·August 05, 2022
Japanese hand planes, like all things, need a little TLC with use. When the side grooves that hold the blade in place begin to loosen, and the blade is able to slide beyond the opening of the mouth with a few taps of a hammer, it's time to adjust the tightness. Here we explain in detail everything you need to do to either fix loose or tight side grooves. You don't have to be a seasoned craftsman to follow these steps.
In this article, we go over these important, easy-to-follow steps to help tune and adjust the tightness of your hand plane.
1: Fixing Loose Side Grooves
When the side grooves that hold the blade in place begin to loosen, and the blade is able to slide beyond the opening of the mouth with a few taps of a hammer, you can use a piece of paper on the bed of the hand plane to adjust the tightness of the side grooves.
The ideal paper thickness is either a business card or a post card.
To tighten the side grooves, first cut out a piece of paper to the same dimensions as the bed of the plane that the blade rests upon.
Next, glue the paper onto the bed.
Then, insert the blade and check to see if the issue is fixed.
2: Fixing Tight Side Grooves
If the side grooves are too tight and it's difficult to remove the blade, you will need to sand the bed to loosen the fit.
To find out what areas of the bed are causing the tightness, apply a light coat of oil to the bevel-side of the blade and insert the blade into the hand plane.
Then, remove the blade and identify any oil marks on the bed of the plane. These marks indicate the high spots that need to be filed down to loosen the fit of the blade.
We recommend using a flat mill file that is around 150 millimeters long. Because mill files have finer teeth than wood files, you are less likely to take off too much wood when tuning the bed of the plane.
Also, single-cut files are better suited for this purpose than double-cut files.
To avoid filing off too much wood, take your time and do it slowly, little by little. When you think you have removed enough of the high spots, insert the blade and check to see if the tightness is fixed.
Check out our other articles for more great tips on how to care for and maintain your Japanese hand planes!