Making a Spar Plane Inexpensively
Bob Smalser, Seabeck, WA
>James Krenov shows a simple way to make custom wood planes in his book, �The Fine Art of Cabinetmaking�. The only problem for a boatbuilder, who might need a half dozen spar planes of different sizes, is the price of high-quality, aftermarket irons of sufficient thickness for a wood-bodied plane.
There is a less expensive way to a high-quality end, and that is converting old flea-market woodies. Auburn, Ohio Tool, Fulton, and dozens of other 19th-Century manufacturers competed hard with each other in quality and value. These planes are generally beech with thick, tempered cast-steel irons�some of them laminated like today�s Japanese blades�and mild steel cap irons. The ones the collectors don�t want are worn, scruffy and cracked with the logos stamped into the wood illegible�. you see them at swap meets and on Ebay for as little as 5 dollars each. We�ll use the same modern-glue rationale to make permanent repairs as Krenov used in making split-bodied planes. Make sure the one you buy has the original thick iron with some length left in it and not too much pitting on the back side near the edge.
Here�s an old, worn-out Ohio Tool coffin smoother above I�ll remake into a spar plane. I�ve jointed the cracked sole flat, and will laminate a thick, squared-up piece of beech to it. How thick? Thicker than the plane and cap iron assembly will penetrate the jointed sole of the body�.plus a little more for good measure. Also note the rapid technique for marking center lines in the photo.
I laminate using boatbuilder�s epoxy�a coat of unthickened on each faying surface followed by a thickened coat�I worked the unthickened coat into the cracks in the sole using gentle heat for penetration�and used a lead-weighted mallet as a �clamp�. Epoxy doesn�t like a lot of clamping pressure.
I use the same heat technique to repair the many cracks in the plane�s top side�cleaning those cracks with a thin solvent, first like acetone or trichloroethylene to remove any oil. I dye the epoxy to match the wood, merely for cosmetics.
Old woodies like these generally wear much more at the toe than heel, which changes the iron�s angle of attack, so I rip the sole parallel on the table saw.
Now I chop out a new throat from the throat side of the plane. The rear of the throat is a 45-degree angle and the front bevel of the throat needed to clear shavings is about 20 degrees in the opposite direction. I merely index the chisels against the plane body and tap and pare.
I continue to remove wedge-shaped waste until the back of the throat and the front of the throat meet�
�in a nice, clean �V� about halfway to the bottom of my over-thick sole stock. The cleaner and more accurately-indexed your new throat, the cleaner the resulting mouth will be�. which I�ll cut shortly on the table saw.
To lay out the eventual depth of cut of the cove I am about to mill, I measure the depth to the bottom of the �V� and transfer that measurement to the plane body.
Continued�
