I am an experienced woodworker but a first-time luthier. I am working on my first-ever instrument build, an F-style mandolin with a spruce front and maple back. I am following Siminoff's book, "Constructing A Bluegrass Mandolin: A Complete Technical Guide." To carve the two plates, I was looking for a single tool that was durable, simple to use and would last years. After consulting a couple of professional luthiers, I went with the small (10mm, I believe) D'Angelico plane sold by LMI. I also ordered a spare iron. The irons, made by Hock, seem very high quality.
The tool showed up yesterday. As with every plane I ever owned, the first thing I did was remove the iron and polish the back of the iron to ensure it is absolutely flat. Next, I took the iron to my set of three progressive diamond sharpening plates (coarse, medium and fine) and sharpened the iron bevel, careful to maintain the rounded bevel that works so well with the plane's convex sole. Admittedly, I did all of this by hand. However, I examined the bevel along the way and was confident I was maintaining the bevel properly. Finally, I stropped the iron on my usual leather strop with honing compound applied.
I placed the iron back in the little plane, bevel up (the way it arrived) and I picked up a scrap to test it on. This wasn't just any scrap--it was a back plate that I had cut out on the bandsaw already but had a number of defects. (I should note here that for budgetary reasons and because this is my first mandolin I am not using an extremely fancy species of maple. I am using typical "hard" maple that happens to have a bit of curl to it.) I took a few test passes with the little D'Angelico plane and noticed a bit of chatter and tearout. So I loosened the plane's set screw, pulled the iron a bit back in to the plane to be less aggressive. A few more passes and the plane got caught up and tore out more wood. I went through this a couple of times until the iron was pulled so far back in the plane that it wasn't making contact with the wood.
I thought perhaps I had sharpened the iron improperly. So I took it out and went back to the diamond plates, going through my whole sharpening process once more. When it was done, I tried it on the maple back plate again. Once again, I got no actual shavings like with a typical plane. Instead I just tore out a few hunks of wood and scared the maple.
I switched out the maple with a piece of scrap spruce. And while the results were improved (due to the softer species of wood, presumably) I was not getting the kind of shavings that I am used to from any other plane.
What am I doing wrong? Are these irons not meant to be sharpened as other plane irons are? Could this possible be caused by my technique? It's a simple enough tool but I realize some tools have nuances around their use. I'm just not sure what else could be causing these problems.
Thanks for any help you can offer.
Mark
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