On 2/9/2018 8:42 PM, Ed Huntress wrote:
On Sat, 10 Feb 2018 08:59:37 +0700, John B.
wrote:

On Fri, 9 Feb 2018 13:29:20 -0700, Bob La Londe
wrote:

I'm finishing up some details embossing press dies in steel, and I'd
like to do a little bit nicer job. They flat part of the plate is
pretty easy. I go over it with a diamond hone, then some fine grit
paper, and finally hit it with the buffing wheel and some polishing
compound. Comes out looking fairly decent.

The embossing part looks looks pretty good, but I'd like to make it
look
better. The finish pass with the smallest ball end mill leaves a
pretty
good looking finish, but there are fine tool marks if you look close.
The big old buffing wheel just won't fit down in all the fine
details so
I was thinking of maybe making a tiny soft cloth wheel to fit a rotary
hand piece mandrel and having a go at it some polishing compound.

I have a few failures from the project on my bits and pieces shelf I
could test it out on, but I'd like to know if I am just chasing my
tail.

Perhaps not want you want but I might mention that hand engraving,
guns for example, are polished surfaces with hand cut depressions. The
actual engraved portions are not polished or smoothed in any way.

If you really *do* need a polish, the traditional way to do it is with
slips (shaped hand stones) and die grinders equipped with points
(cylindrical buffs, longer than they are wide, made of felt and
available in a variety of end shapes) The last handwork I saw of that
type, over 30 years ago, was being done with die grinders and
rubberized abrasive Cratex points, and polished with felt points.

A lot has to do with how fine and complex the details are. But a
complex coining die might require 30 hours or more of handwork. Often,
depending on the machine finish, it starts with jeweler's files and
diemaker's rifflers, which are like woodworker's rifflers but with
very fine teeth.

These are traditional moldmakers' and diemakers' skills. They've been
largely replaced with advanced ram-type EDMs. It's a lot easier to get
that finish on a piece of graphite or tellurium-copper electrode than
on steel, and the finish you can achieve with today's EDMs, using
copper or copper-alloy electrodes, amounts to a medium-high polish.



Thanks Ed. I am not quite ready to step into EDM, so polishing tricks
may be the ticket. I didn't pickup the graphite mold job, so I have not
dedicated a machine to being destroyed by cutting graphite just yet.

I probably have a "good enough" finish, but I'd like to do better.