edge jointing and the mysterious vanishing camber

[adrian]

The blade where I thought I'd nicked the edge with the honing guide was actually an A2 veritas blade, but I assume that would be less rather than more prone to damage. Clearly I'm going to have to try this process again. Thanks for doing the test! (I noticed that your honing guide has a different piece for the blade stop. Mine is painted black.)

I finished up with the cherry and moved on to gluing. I did joint about 20 feet of 1.5" wide softwood to aid in the gluing process, and another 25 feet of 3 inch wide softwood (with knots) without observing any deterioration in the performance of the planes---the mysterious concavity has yet to reappear.

 

[ivan]

By "lateral setting" I mean the setting of the lateral adjusting lever, (not the position of the plane over the edge you're planing.) This can "creep" in use and take you unawares. You might re read this section my post above with this in mind.

If a blade has a crown of (say) 4 thou , and you set the blade to take a two thou shaving, and you plane a shaving from piece of flat, pre-planed timber, the shaving with not be the full width of the blade. If you keep planing over the same track very soon the plane will stop cutting altogether, (see post above) It is very difficult to crown a blade to an exact number of thou (unless you use a very expensive set of Odate crowning plates) so you may well be seeing this effect when you plane an edge. (on an edge you keep going over the same track) Hence my suggestion to plane with a straight edge, easy to get with a Veitas wide roller, and get the feel of the plane before trying fancier stuff with a cambered, or crowned blade.

When you get more used to the feel of the plane, you can begin to hone a slight crown so you can still get a full width shaving of about 2 thou, which tapers out to whispy thin-ness at each edge. (Bear in mind setting the same blade for a thinner shaving will result in a cut less than the full width of the blade. Being able to estimate a shaving thickness by observation is another planing skill to develop)

 

[adrian]

By "lateral setting" I mean the setting of the lateral adjusting lever, (not the position of the plane over the edge you're planing.) This can "creep" in use and take you unawares. You might re read this section my post above with this in mind.

I understood this. My observation was that the plane was taking a full width shaving when positioned a certain way over the edge. If I shifted the plane to one side or the other than the shaving would no longer be full width; rather it would remove material only from one side of the workpiece or the other. If the blade were shifting laterally in use, then I would observe a change in the location of the full width cut. Since I did not observe such a shift, I believe that the lateral adjustment was not creeping in use.

If a blade has a crown of (say) 4 thou , and you set the blade to take a two thou shaving, and you plane a shaving from piece of flat, pre-planed timber, the shaving with not be the full width of the blade. If you keep planing over the same track very soon the plane will stop cutting altogether, (see post above).

This applies to shaving a face, but not an edge. In the case of the edge, the cut is the full width of the wood, so you never form "rails" that keep the plane from being able to cut. (In principle this same thing would happen even without a crown because the plane has edges where it does not cut, so if you had a straight blade and you worked in exactly the same track the plane would start riding on the uncut region where those edges are.)

It is very difficult to crown a blade to an exact number of thou (unless you use a very expensive set of Odate crowning plates) so you may well be seeing this effect when you plane an edge. (on an edge you keep going over the same track) Hence my suggestion to plane with a straight edge, easy to get with a Veitas wide roller, and get the feel of the plane before trying fancier stuff with a cambered, or crowned blade.

Since my shavings are the full width of the edge the situation you suggest cannot arise. To get this situation on an edge would require an extremely large camber such that a centered shaving is not full width on the edge. (For a 2 thou shaving and a 2 3/8 inch blade the camber would have to be 0.03 inches at the edge of the blade, assuming a circular blade profile and 45 degree bed angle. My camber is about a tenth of that.)

When my blades were flat the edge of the blade left trails through the wood, which I didn't like much. I'll admit that the period where I worked with flat blades was fairly short. For a long while I was sharpening on dished waterstones, so everything had a camber (chisels too, presumably). Once I corrected this I had a period with flat blades, but I observed the plane tracks problem and I learned about Charlesworth's approach and so I applied the camber.

It took a significant amount of time for me to camber the blades, so I'm not inclined to grind off the camber for a short experiment. I do have two flat blades left for bevel up planes that I could experiment with. But what am I supposed to be trying to learn? What experiments should I conduct? What should I be paying attention to? (I'm not entirely sure I believe in the theory that I should adjust the tool into an abnormal state to try to gain insight into its function since what I really care about is how the tool behaves in normal use, which I think means with a camber.)

 

[o_LuCaS_o]

Hi!

Adrian, it's been a long time since this thread was alive. I found it a few days ago and read it with a lot of interest. How is Your edge jointing going? Did You ever encounter the problems You mentioned here with the concave camber and persistent bump? I've been doing some edge jointing myself and noticed a few things about bumps. I've been planning a piece of birch, which I thought is one of the most pleasant woods to plane, but the piece I have is a little knurled. The grain often changes directions, also on the edges. The result is tearout, even with thin shavings and a higher pitch angle (LV BUJointer w/54deg angle). Near the end of one of the edges I encountered tearout and in that spot it was hard for me to "dig in" with the "stopped shavings" method, leaving a bump near the end. Was that a case in your problem? You also mentioned a squeaky noise while planning. Maybe it was a knot You had in the edge, that was hard to take down with the jointer.

The thing I'm wondering about is, if grain direction changes giving tearout can prevent one from getting a really true surface, or at least make the task harder? Should one locally change the planning direction to take the tearing spots down and then return to the globally proper direction?

Regards, Lucas.

 

[adrian]

Hi!

Adrian, it's been a long time since this thread was alive. I found it a few days ago and read it with a lot of interest. How is Your edge jointing going? Did You ever encounter the problems You mentioned here with the concave camber and persistent bump?

I think it may be better to start a new topic instead of reviving this ancient one.

I have not gone back and re-read this thread and I don't recall the problem I was having with the persistent bump back then. With the vanishing camber I quit using the Clifton plane and haven't had that problem occur with any of my other planes. I've had various other issues arise in edge planing, and you can probably find threads about them posted here if you search. I tried match planing but it didn't work because the grain of the two boards went the opposite way and even when I tried a 70 deg cutting angle I still got tear out. I had the mystery of the bevel up plane that stops cutting in 15 minutes while the bevel down plane cuts for ever.

I've been planning a piece of birch, which I thought is one of the most pleasant woods to plane, but the piece I have is a little knurled. The grain often changes directions, also on the edges. The result is tearout, even with thin shavings and a higher pitch angle (LV BUJointer w/54deg angle). Near the end of one of the edges I encountered tearout and in that spot it was hard for me to "dig in" with the "stopped shavings" method, leaving a bump near the end. Was that a case in your problem? You also mentioned a squeaky noise while planning. Maybe it was a knot You had in the edge, that was hard to take down with the jointer.

The thing I'm wondering about is, if grain direction changes giving tearout can prevent one from getting a really true surface, or at least make the task harder? Should one locally change the planning direction to take the tearing spots down and then return to the globally proper direction?

You aren't clear if 54 degrees is your cutting angle or your blade bevel angle. If it's your cutting angle you could try raising it more. I was using 59 and some people use higher.

It's been a while since I edge planed, but when I did I had wood with some small knots where the grain reversed. As I recall, I did have more difficulty in planing those regions and getting the surface flat. Could something different happen to the fibers when planing the wrong direction? Is it possible that when the fibers are standing up that the plane sort of "pushes them over" and then they pop back up so that they aren't getting cut off the same way? (In other words, that you get more fiber spring back?)

I have certainly changed directions at times when the grain reverses. However, I end up with a bump at the point of reversal when I do that. To remove the bumps I have to be able to plane the neighborhood of any point on the board all in the same direction.