I've seen sets of these available as gasket hole cutters, Pete. Some
versions have holes in the wall of the tube section for inserting a tool for
ejecting the slug.

I've seen the tapered cut (to form the cutting edge) on the inside too,
making the OD the desired hole size.
I don't actually recall the term/name Dinker though, just remember them as
being referred to as hole cutters or cutting punches.

The forming of the sharp edge starts as a chamfer, but ends up being a
bevel, technically speaking.

From back in my early days as a pup, I would use nails for punches, and
sometimes still do. The point is ground or filed away, leaving a flat end
with a sharp edge.
Using the endgrain of a hardwood block as a backer, tapping the nail/pin
thru the sheetmetal, leather, rubber etc, produces a fairly clean hole with
little distortion in the sheet.

--
WB
..........
metalworking projects
www.kwagmire.com/metal_proj.html


"spaco" wrote in message
...
A friend just asked me how I might go about making 1 1/4" dia. round holes
in the bottoms of tin cans. He was thinking of making a chassis punch to
do the job. He needed an excuse to do something on his South Bend Lathe.
I suggested making a "Dinker Die", as an easy to do, faster
alternative. I googled "dinker die" to get a .jpg to send him, and
didn't get many hits. This surprised me. I thought everyone knew about
them, but apparently not.
So, here's what I wrote him on the subject (use tool steel if you want
it to last):

Yuh know, us blacksmiths chisel cut sheet steel up to 1/16" thick or
more, cold, with a sharp cold chisel. I have several dozen of these that
I have made. I have a set of them that are curved, so I can produce
radii from about 1/4" to about 2".
You could also turn a "dinker die" in your metal lathe. It's just a
piece of tubing (water pipe, etc.) whose ID is correct for the hole size.
Then you turn a chamfer on the outside of the tubing at about 60 degrees.
all the way towards the ID until it is sharp. Just set the sharp end on
the tin, backed with wood, and hit it. You simply punch out a slug.
I have made many of these over the years. Sometimes its the hole that
I want and sometimes its the slug.
----------------------------
These work great for punching holes in rubber, leather, canvas, etc., too.


Pete Stanaitis