I wanted approximately a 6° angle on the taper (3° either side of an imaginary center line) and calculated that over 8 1/2" length of taper I'd need 3/8" diameter at the small end and 1 1/4" diameter at the large end. So I glued up some oak, octagonized a 1 3/4" square blank and put it on the bungee lathe.
|Checking the taper for straightness|
To guide my sawing a kerf lengthwise through the tapered section, I marked some lines carefully along the length of the taper. Having marked crosshairs on both ends before turning helped to get the lines 180° opposed to one another.
For the blade of this tapered reamer, I'm using a really crappy and cheap garage sale saw that I've been cannibalizing for scratch stock blanks.
|Blade marked out|
|I had hammered most of the set out of the teeth to get a kerf that will match the blade's thickness|
|The blade cut out and the edge filed to match the taper of the reamer|
|Bladed installed in the reamer: the saw's teeth are just barely showing|
|On the other side, the edge is proud of the taper by about 1/32"|
I bored a through hole in some pine and made the first test taper.
|The first cut|
|The tapered hole showing the reamer's teeth marks|
This is good enough for a prototype and proof of concept. Next I'll write about making the other part of the equation: the tapered tenon-cutter.