Hey David,
Rich’s advice on inletting the plate into a stock that is close to finished dimension is spot on. In addition to that, Ian explained to me that you need to basically inlet straight down as well. You can always adjust the inlet slightly forward as you go. It took me two or three explanations before that made sense to me. Once I got it organized in my mind, I’ve done a better job inletting complicated buttplate extensions.
Also, his advice to solder a piece of brass under the extension is a sound one. I recently applied that principal to help a friend repair his great-great grandpa’s Belgium shotgun. There was a crack in the screw hole of the bottom tang through which the main stock bolt passed. I soldered a piece of steel to the inside of the tang, relieved the stock to accommodate the increased thickness, and re-drilled the screw hole. The reinforcement made the area stronger than ever would have been attainable by trying to repair the crack alone. The piece wouldn’t have to be all that thick, maybe 0.025-0.032” stock that could conform to the gentle underside curve of the extension. A low temp solder would reduce the potential for heat warping the thin metal.
Another thing to consider for next time might be to make the terminal part of the extension shorter overall. I think anytime you have a piece of metal that long and thin, you are going to have an issue trying to keep that extension in the inlet where it belongs without pinning. That’s one good reason to start out with a heavy piece of stock (0.090”)” to begin with. You have more leeway when taking metal off.
I really like how the finish turned out. Looked like you had a beautiful piece of curly maple to begin with and your finish really seemed to highlight that. One thing that caught my eye though was that transition area mid-stock behind the nose of the comb. To my eye, that transition is way too abrupt. The picture of your unfinished gun/repair shows both sides of that transition very well. In general, that area should transition gradually and blend in with the wrist and butt. Many of the wrists you see on fowlers are also cylindrical in shape as they transition into the butt. Buchele’s book had a good illustration of that concept.
See you in class!