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Sharpening Block Planes Print  |  Back

From: book: The Complete Guide To Sharpening

Page 1 of 1

Whereas bench planes are generally used with the grain, the block plane was designed to work end grain. Today it is used for all types of cuts, but its name comes from its original use in dressing the top of butchers’ blocks. As the various ways to shape the blade are discussed below, keep in mind that the recommendations are aimed at effective end-grain cutting.

Block planes provide an opportunity for some very innovative sharpening, but they are probably among the worst-made planes on the market today. For example, of the four block planes made by Record and Stanley (see the photo below), only the Record #09-1/2 has a lever cap that is long enough. Since block planes do not have cap irons, the lever cap has to do double duty whenever a cap iron would be desirable—usually only for face- or edge-grain cutting with a standard block plane; a cap iron is not needed when cutting end grain. Be cause these planes have only a narrow bed lip and a frog post for the blade to rest on, it is desirable that the lever cap extend at least to a point above the bed lip; otherwise, it will be pressing on an unsupported section of the blade.
From top to bottom, the Stanley #60, the Record #060-1/2 (both low-angle block planes), the Stanley #9-1/2 and the Record #09 (both standard block planes). Only the Record #9-1/2 has a lever cap that is long enough, and then just barely. It would be better if the lever cap were 1/8 in. longer.

This article is excerpted from The Complete Guide To Sharpening by Leonard Lee.
 
LOWERING THE BED ANGLE ON A BLOCK PLANE
If you have a short lever cap on your block plane, it will apply pressure behind the machined portion of the bed caus ing the end of the blade to be lifted away from the bed. To reduce blade chatter caused by this flaw, you have to lower the bed angle so that the blade rests on the bed at the mouth, not 1/4 in. back of the mouth. To dress the bed, strip the plane (removing the adjustable nosepiece) and file the bed, letting the file pass through the open mouth and using the frog post as a guide since it is several degrees below the blade line on all modern block planes. (The low post is another flaw, but at least it works in your favor for this process.)

If you find it too difficult to get even seating of the tensioned blade along the entire bed, you can relieve just the back part of the bed so that the blade only touches at the mouth. That is still better than the condition you are correcting.


The lever caps on both of the Stanley block planes are about 1/4 in. short of what they should be, the lever cap on the Record #060-1/2 is nearly 1/2 in. short. To compensate for this, you should lower the bed angle by 1° or 2° to ensure that the pressure of the short lever cap does not cause the blade to arch away from the front of the bed (see previous page). Assuming that you have done that and all the other necessary tune-up procedures, you can turn your attention to the blade.

BEVEL ANGLES
The standard block plane (#9-1/2) has a bed angle of 20°. Since the blade is used bevel up, if we put a standard 25° bevel on the blade, we will end up with a cutting angle of 45°. This just happens to be the same cutting angle that we have for a smoothing plane, which has a bed angle of 45° but where the blade is used bevel down. So when you sharpen the blade of your standard block plane at 25°, you produce what is in essence a smaller smoothing plane.

But there is nothing to say that you can’t put two bevels on a plane blade. You can easily grind and hone a 15° bevel on the blade and then put a 10° back bevel on the face of the blade (as shown in the top drawing at right). This would still leave you with a 25° included angle, but you would now have reduced your cutting angle from 45° to 35°. You are still left with a 10° relief angle, which is perfectly adequate for block-plane use.

Possibly more significant, you have sharpened the blade of your standard block plane in a manner that will give you a lower cutting angle than someone who sharpens a low-angle block plane in a standard fashion (12° bed angle plus 25° bevel, a total of 37°).

All of this dazzling footwork with bevel angles now raises the question, “Why do we bother with a low-angle block plane?” It is a good question. The answer is that lower bed angles not only let you use lower cutting angles but they also align the blade more closely with the direction of cut, there by minimizing chatter. The lower you make the bed angle, the closer you approach the function of a chisel, which does not chatter.

This article is excerpted from The Complete Guide To Sharpening by Leonard Lee.

In practice, whether or not you get chatter with a low-angle block plane depends almost entirely on the fit of the blade to the bed and how well you can tension your blade with the lever cap. A well-tuned standard block plane will chatter less on end grain than a low- angle plane with a blade just as sharp but that has not otherwise been tuned. In my view, once the blade is clamped in position properly with a lever cap of the right length, bed angles become a secondary consideration; cutting angles remain significant.

Given the curious state of block- plane production today, I would look first for a block plane that can be tensioned properly (e.g., a Record #09-1/2), get an extra blade, and then have one blade sharpened for regular block- plane use and the other blade sharpened for low-angle use.

Whether or not you do any or all of the things suggested here is almost incidental to my purpose. What is particularly important is that you become comfortable with the principles involved so that you can tune your planes and shape their blades to suit your requirements and your practices.

This article is excerpted from The Complete Guide To Sharpening by Leonard Lee. ©1990 by The Taunton Press.