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
illegibly. You see them at swap meets and on eBay
for as little as five 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 which
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.