Sharpening chisels consistently, part 2

2 04 2010

After my previous post about sharpening chisels, I received a helpful comment which informed me that another way to set angles consistently for sharpening chisels is to make a blade projection board. This takes just a little bit of work and has many advantages over the marking method I wrote about before.

The angle of the blade in the honing guide is determined by how far it projects from the front, and so the key to getting the same angle every time is to make sure that the blade projection length is the same every time. Having a physical guide is faster and more precise than visually lining up a mark.

Making the jig is simple. First, decide which angles you want to use for the primary and secondary bevel. Next, put the blade in the honing guide and adjust the blade projection until you get the desired angles. For each angle, measure how far the blade sticks out. Then take a board and attach stops that are those distances from the edge.

To gauge blade angles, I used an application for my iPod Touch called Clinometer. Even though it’s not particularly important to set it at a specific angle (27 vs. 28 degrees, for example), it’s still nice to know what the angle is.

Measuring the angle of the chisel in the guide, on a glass plate (the other side happens to have sandpaper glued to it).

I made the jig with stops for 25 degrees for the primary bevel, and 28 degrees for the secondary bevel. The stops were placed at 41 and 34 millimeters.

To use the blade projection board, just put it against the front edge of the honing guide, move the blade until it contacts the stop, then tighten the screw to lock it in place.

Using the jig to set the blade in the honing guide. After taking this picture, I wrote the angles on the jig.

Plane blades will require a separate jig, since they clamp in a different spot on the honing guide, and because they may be set at different angles. Very simple and effective — I like it!

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One response

2 04 2010
Olly Parry-Jones

Glad I could be of help. ๐Ÿ™‚

Nice iPhone app!! ๐Ÿ˜€

Olly.

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