Coffin Smoother - 2503

With the infills now temporarily pinned in place I turned to one of the most consequential internal operations on the plane: bringing the wooden bed into perfect continuity with the steel at the mouth. This step is not about appearance, with the blade in place none of this work will be visible. Any bump, hollow, or discontinuity here will telegraph directly into blade support, so the goal is a single, uninterrupted bearing surface from the rear of the bed through the mouth. That's the theory anyway, in reality getting 70% of the surface co-planar will be a win. I used dry erase marker on the iron itself to read contact, working slowly and deliberately to remove only the high spots in the wood. The process is highly repetitive: each pass shows not just where material needs to come off, but how the bed and shell are relating to one another as an assembled system.

What I was looking for was consistency rather than speed. Uniform contact across the width of the iron and right up to the mouth, without biasing the shell or closing the mouth even slightly. This is one of those operations where progress is measured in feel and witness marks rather than visible change, and it rewards restraint. I'm aiming for ~70% of the surface to bear with a preference for the surfaces immediately around the mouth. I'm getting there, probably 40-50% right now, but with the gaps that exist near the mouth. I did some testing with feeler gauges, and it's about a .002 gap right now between the metal at the mouth and the back of the blade.

Once I get that gap closed, the remaining interior steel can be brought up to final finish, after which the infills will be permanently locked in place.

Fitting the infills to the shell is a slow methodical process. I determined the best way to get a clean shoulder line for the fit between the wood and the metal was to shim and scribe. That is, a know thickness spacer (0.250" in this case) is placed on top of the sole and then the stuffing is shaped until it firmly registers on that shim. At that point a purpose-made scribe that puts a line exactly .250" above a reference edge is used to mark the shoulder. After that it's a simple matter of removing the material right up to that line.

Having now fully peened the shell I am realizing some challenges of the design choice I made for how to structure the dovetails. The traditional "double dovetail" is what I've seen on most modern makers' planes as well as read about. However, examining the antique example, the tails coming off of the sides were visually straight. So I replicated that in this plane. The end result, likely due to my inexperience, was that the peening process lifted the toe end of the sides off of the sole as the metal pushed it up. If I'd been able to peen the ends of the tails on the sides first, it would have locked it in place and prevented that from happening, but a combination of the design and not leaving enough meat on those parts prevented doing that. I will redesign the side for future planes. Fortunately, the sides are structurally locked in; reasonably application of force doesn't result in any movement. So I will fill the gaps with some Devcon 10110 and move on.

Speaking of moving on, the lever cap and screw that I sent out for machining came in today and are gorgeous. I'm very happy with how they turned out.

Using a two-part bending form I can fairly quickly bend the sides to shape using the force of a vise or clamps to bring the sides together. Anticipating the spring-back and shaping the form accordingly is much trickier. On this plane I managed to get the sides close off the form and then used various combinations of a makeshift anvil (1.5" metal rod stock), a baby sledge, and squeeze clamps to adjust the curve until it was close enough to the curve of the sole. Once it was close, it was painstaking work with the file to file off the high spots in each dovetail socket, test the fit, mark the new high spots, file them off, over and over until the fit was where I wanted it. My shop log shows that as about 4 hours of work, though it felt like a lot longer.

A few more hours of filing got me: undercuts for the metal to flow into during peening, a mouth roughly angled where I want it, and a mouth extended out to meet the sidewalls. I get the feeling there is a lot of technique to develop here that would improve speed and accuracy on future planes. For now, I'm just glad to put my files down and move on.

I'm stepping up to a full-sized plane for my next effort. This will be modeled closely on an old Spiers infill smoother in my collection. Many hours went into closely measuring the plane and modeling the metal parts in CAD so I could outsource rough cutting of the metal to a laser to jump start my process. This will be all steel. Mild steel for the dovetailed components, stainless for the lever cap and screw. I haven't decided on a stuffing wood yet, but will go shopping once I have a shell made.

The dovetail pattern on the Spiers smoothers in my collection is a bit different from the one I executed on my last plane and what I've seen on modern two-metal dovetailed planes. That is, looking at the plane fro the side it looks straight, like a box joint, rather than showing the characteristic dovetail outline. Since it's supposed to blend in to the side when the metals are the same for the side and sole, it shouldn't matter aesthetically. It shouldn't be any harder to execute, and I'll see if it saves any time when it comes to the peening.

The first challenge, however, will be bending the metal for the sides, which means making up a bending form.