Square blade edges

[Michael Bulatowicz]

Rather than risk derailing the thread about the Veritas MKII honing guide, I am starting a new thread on a relevant question.

Specifically, when, in your experience, does it really matter if your edge is slightly out of square on chisels or plane blades? I'm not talking about an unintentional skew chisel or a plane blade skewed beyond the limits of the lateral adjuster--just a slight skew.

Maybe I'm misconstruing things I've read here and elsewhere, but there seems to be a lot of effort that goes into getting the edge perfectly square to the sides of the blade and stress associated with a small skew. My work seems to tell me that a perfectly square edge is almost always unnecessary and a small skew is most often nothing to worry about. Am I missing something?

To be clear, I am not talking about ignoring manufacturing issues on a honing guide (which I agree are a problem independent of whether or not the skew itself is an issue): this is a general question about the squareness of the edge itself that probably applies more to those of us who sharpen freehand.

Thanks in advance.

Michael Bulatowicz

[Jim Koepke]

The only problem that occurs to me is on a mortise chisel. A skew may cause it to twist in the cut.

If a chisel is noticed to have any skew, my usual practice is an attempt at working the skew out when sharpening it in the future.

jtk

[Michael Bulatowicz]

The only problem that occurs to me is on a mortise chisel. A skew may cause it to twist in the cut.

If a chisel is noticed to have any skew, my usual practice is an attempt at working the skew out when sharpening it in the future.

jtk

Thanks, Jim.

That mirrors my experience and practices. While I agree for my own work with mortise chisels, it occurs to me that the need for squareness may depend on the technique used for mortising (which is why I didn't call it out).

[david charlesworth]

The squareness of edge may be important in a Shoulder plane, as they have very little lateral adjust.

Bench planes have a huge leeway,

David Charlesworth

[Rafael Herrera]

I have a Millers Falls no. 4 bull nose plane, one side of the blade protrudes about 1/32" higher than the other. I could not adjust laterally so that the blade would be level with the plane sole. I decided to grind away the protruding edge to see if that would solve the problem. The blade now has a visible skew. The plane sole and sides are square. It's possible the blade bed is milled badly, but re-shaping the blade seemed like the best approach to tune this blade. The blade is still needs a little bit of grinding to make it protrude level at the sole. I'll add some pictures after work.
Rafael

[James Pallas]

The photo shows a 1” chisel with a .010 skew from freehanding. It’s time to correct it. As you can see it puts it out of plumb a good bit over its 12” total length. You can definitely notice it when trying to hold it in a gauge line.
Less then this is less noticeable. It’s at about this point that it starts to annoy me.

[Jim Matthews]

I sharpen freehand. While I suspect all my blades are skewed, it's pronounced on smaller (more narrow) chisels. I tend to hold blades too long, right handed.

I submit that is where a skew causes the least trouble.
Broader blades ground askew plow toward the "leading" edge. I only notice this on my shoulder plane.


I use a Sharpie Marker to take greater care on plane blades that need a little camber.

[Rafael Herrera]

In my case I have to force a skew on my blade.

Here is the bull nose plane.

20200414_235133.jpg

Here you can see how the blade edge is not coplanar with the sole and a top view.

20200414_235807.jpg 20200414_235545.jpg

This is the blade, I already worked on it,but I need to increase the skew a little more to make the blade edge co-planar to the sole.

20200414_235404.jpg

I think the problem is with the plane bed, the blade bed does not meet the plane sole at the same angle on each side. See the difference in thickness?

20200414_235925.jpg

Re-shaping the blade is feasible for me, re-milling the blade bed not so much.

Rafael

[Jim Koepke]

Re-shaping the blade is feasible for me, re-milling the blade bed not so much.

You would be surprised how easy it is with a file sized for the job.

jtk

[James Pallas]

The infamous #75. I think it’s been about a year since the “thing” reared it’s ugly head. It’s not technically a bull nose plane. Someone has ground the sole down to be coplaner with the nose. That is most probably why the bed appears to not be level. It’s most likely not the bed but the sole that is off. If you really need a bullnose plane you need a bullnose plane like a #90. (I think that’s the right number”. I have and use a #75 but not as a bullnose plane.

[Robert Hazelwood]

Mortising. Having much of a skew tends to make the chisel dive to one side and chew up the mortise wall.

[Chris Fournier]

I've never lost any sleep over square edges on my hand tools but early on it was pretty hard to get one! In planes there is plenty of tolerance to align your cutting edge with the sole. I use a bench grinder and my set up makes square edges pretty straight forward. I'll often grind freehand and keep an eye on my progress with a small square at my side. A light grinding touch gives you plenty of opportunity to chase square. Now "sharp" will keep me up at night...