I have been feeling
the need the last few years of either getting or making myself a sensitive
drilling attachment. I admired Sherline's sensitive drilling attachment (Part
#1012), but felt I didn't have the bucks to get one, so, I made one essentially
based on their model. Below are the individual parts pics, and some assembly
and final assembly. Drilled some holes in aluminum with a small #56 bit, and
worked great.
I didn't know of a
place in town to get the bearing for pulling down the drill, so I got one at
our local Ace store in their Hillman boxes. Not the best, a little wobbly, but
allows me to pull down on the lip flange of the bearing and control depthing
with the drill bit.
Some notes on
materials and what I did: The brass tube is 13/32 O.D., the inside shaft is 3/8
O.D. cold roll, the shaft fits inside the brass tube with hardly any side shake
to speak of. The drill body is made of aluminum, internally tapped and threaded
3/4" 16 T.P.I. The drill body was drilled to near size of the tube, then
bored out to allow the brass tube to be pressed into the body and loctited in
place. The set screw guides the steel shaft and also prevents the brass tube of
ever twisting in the drill body. I did some knurling on the main shaft so the
bearing could be fixed in place, as the tolerances of the bearing were a little
sloppy.
The whole project
from start to finish would have taken (for me) about a full day with all parts
at hand, fabrication of other parts, and cutting threads on the main shaft for
the Jacobs chuck with the Sherline. One of the larger purposes I intend on
using this for is to make Geneva stripes on some watch and clock movements,
along with spotting or perlage besides drilling.
What an interesting restoration project. Thanks for sharing.
ReplyDeleteRegards
The Goldgena Watch Project