Reply To: Uncooperative moulding plane advice

#768066
Ed
Participant

I suggest a slightly different approach than that of YrHenSaer as it can be quite technical to adjust the sole of the plane, yet it is quite possible that the sole is perfectly adequate even if one can detect imperfections. Therefore, I suggest that you simply address the blade and try it. I would not mess with the sole unless forced to do so.

Wood shrinks, metal doesn’t. It is common to find old planes in which the iron appears to be too wide for the plane. On hollows and rounds, the blade will commonly project beyond the width of the plane body making it difficult to join up profiles and making one portion of the cut too light and the other portion too coarse. Or, it can cause the corner of the blade to dig tracks into the work no matter how you set the plane.

If you have machinists marking fluid, paint the back of the iron, let it dry, and then load the iron and wedge into the plane. Use a long slender scribe, perhaps an awl, to trace the profile of the sole onto the back of the iron. Have this in mind when you load the iron. You want a minimal amount of iron projecting in order to reduce grinding, but you need enough that you don’t miss spots with the scribing. In the ideal world, you will literally work to the scribe line, just removing it in the grinding, and there will be a few spots that have practically zero grinding. In practice, the scribe line may be back of the edge a bit and is just a guide. Try for the ideal. If you don’t have marking fluid, you may be able to use a wide sharpie, but it may be hard to scratch into the sharpie.

You will be scribing across the gap of the mouth onto the back of the blade, which can be awkward, but that is what must be done. Have the wedge in place. Don’t try to have the blade loose and pressed up against the breast angle of the mouth in an attempt to avoid scribing over the mouth gap. You’ll get the wrong profile. Plane makers often fabricate a scribe that is flat on one edge to ride float along the sole, but tapers to a point from the other side. A skinny awl won’t be perfect, but it will be more than adequate.

If you use a grinder to work the profile, it is best to set the grinding table at close to 90 degrees while you grind the shape. Once the shape is ground in, you then set the grinder table to the appropriate bevel angle and grind in the bevel, ideally not changing the shape (profile) at all and leaving just a whisper of a (flat) line that you grind and hone by hand. If you try to shape while grinding at the bevel angle, you will almost certainly overheat the metal at the edge.

So, I would address the blade first. Even if you find that you want to dress the profile, it shouldn’t be so much change that it would affect the blade profile much, if at all. Personally, I’d be very wary of adjusting the profile. It’s tricky. I would definitely hold a rule up to the plane to see that the toe and heel are in line and not in twist, but if they aren’t there’s little you can do and the plane might function passably anyway. When buying planes, I check for toe and heel being in line first thing and reject the plane if they aren’t because it can be the death of the plane. Your photos look good, though, although I can only see a small portion of the plane.

Don’t forget: When the blade is loaded, you want the edge of the blade pressed dead tight against the side of the plane / mortise. Make sure you load the blade like this when you trace the profile. I’ve actually skipped a step, which is to inspect and correct the bedding of the iron, both in terms of how it rests on its face and how it mates with the mortise and wedge along its side and back. I’m going to gamble that those are fine for your plane, but you should inspect to make sure that the iron loads dead tight against the side of the mortise, that there isn’t any grunge in there holding it away from the wall or making it rock or not load identically time to time.

  • This reply was modified 3 weeks, 3 days ago by Ed.
  • This reply was modified 3 weeks, 3 days ago by Ed.
  • This reply was modified 3 weeks, 3 days ago by Ed.
  • This reply was modified 3 weeks, 3 days ago by Ed.
  • This reply was modified 3 weeks, 3 days ago by Ed.