dowel

vaarna A pin, or block, of wood or metal, fitting into holes in the abutting portions of two pieces, and being partly in one piece and partly in the other, to keep them in their proper relative position.
A wooden rod, as one to make short pins from.
(quote-book)
puhekieltä A piece of wood or similar material fitted into a surface not suitable for fastening so that other pieces may fastened to it.
puhekieltä To fasten together with dowels.
puhekieltä To furnish with dowels.

A cooper dowels pieces for the head of a cask.