A couple weeks ago I presented a problem I was having with my wooden plow plane, especially when trying to plow a groove in end grain.
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| Right side of the plow, showing skates and iron |
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| A closer pic of the skates and iron |
After a bit or playing around and then noodling about it for a while, I realized that the underlying problem was that the iron(s) were not well supported by the skate.
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| On this 3/16" iron, I was able to slip a couple thicknesses of paper between iron and skate |
Let's step back a moment. The lower portion of the front edge of the rear skate has a 90° V-shape that is supposed to fit into the V-shaped groove on the underside of the iron. But I had gaps there with some of my irons.
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| The front edge of the rear skate, between the green arrows, protrudes a little further than the upper edge and has a V-shaped edge. The yellow arrow points to where the heel of the iron's bevel rests. |
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| Here's a typical iron's groove. The pencil points to the spot that mates with the uppermost part of the V-shaped protrusion on the skate. |
Based on some comments I got on a Facebook post, I first tried to file the groove to allow the skate to support the groove better at the heel of the bevel (where I think it would do the most good). But this got nowhere and I was really afraid of causing irreparable damage.
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| Trying some judicious filing |
Another comment was about trying to bend the iron by peening the flat side. This would theoretically make the flat side slightly convex and force the heel of the bevel to make better contact with the skate. I did some work on one of the irons, but either I didn't peen enough or I was afraid of peening too much. All peening was behind the location where the harder steel of the laminated irons ended and went to the location where the iron exits the plane's iron/wedge mortise.
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| You can see the peening marks |
In the end, I just added some 0.005" brass shim material in the irons' grooves. In some cases I needed more thickness than the 0.005" shim, so doubled it up. It's held in place with superglue, so time will tell how that holds up.
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| Seeing how it fits |
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| Glued in and excess glue scraped away, brass filed close to flush |
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| Here's a test groove in end grain pine - much cleaner! |
This was certainly not an optimal fix. I wonder how someone might have handled this 150 years ago. If anyone has further ideas about how best to deal with this, please let me know.
At least this ordeal did teach me one thing that I really ought to have known by now: check your specialty tools on scrap before committing them to the project wood. If you start on a project and then find that the tool needs to be adjusted or modified, it could be very tough to get it back to the exact settings that you started with and so some parts may not align properly - in this case, grooves.
