Brusi of Orkney wrote:
> The tapered tennon is made with a 'spail engine' - there are a heap of
> different names depending on location & trade - if you have seen the
> re-issue video's of the Woodwright's shop, Roy shows how to make one in
> one of the early shows. It can also be used to make rake handles and
> similar long round shafts, depending on how you set the cutting blade.
I've made one of these, and it wasn't that hard to do; basically a bigger
version of a pencil sharpener, in hardwood.
> A tapered hole reamer is used in other medieval trades too, such as for
> making bung holes in barrels as well as wheelwrighting. Big reamers had a
> hardwood body with an inset wedged blade, but it would be well within the
> technology for a tapered all metal tool to be used, I just dont know of
> any surviving ones.
I believe the wheelwright in the Standartarbuch (mid 16th Century) is
shown using a big taper reamer with an all-metal blade--the same kind used
into the 19th Century. So they actually did it, at least toward the end
of the period.
Blacksmiths use a taper reamer that's much simpler: just a tapered strip
of high carbon steel, with relief ground on the two edges to make them
cut. You can grind one out of an old file or piece of leaf spring,
depending on the size you want. I would normalize (heat the tool red-hot
after grinding, then allow to cool in air) in the case of the file,
because it's very high carbon and the twisting might snap it in use.
If you make the reamer first, you can use it to ream the hole in the stail
engine/rounder plane/taper cutter/whatever you call it. Then install your
blade parallel to the reamed surface of the cone.