Number Punches

This post is about another attempt to make identification marks on my reels. Number punches are often used to mark a serial number on equipment nameplates. The resulting characters are usually readable but not very neat; the punch is not accurately placed, it is hit too hard, etc. Is it possible to make neat letting with punches if the are accurately placed and guided to be normal to the surface punched? My conclusion is that it still does not produce neat lettering.

Here are the parts that I made to serve as a punch guide: a base to hold the target screw, a spacer, and a guide for the punch.
IMG_3957
By rotating and/or flipping the guide, four character positions are realized.

This is the punch assembled for the first character position.
IMG_3958

Here I have made all four characters, using a hammer. The “N” and “2” are deeper than the other characters.
IMG_3961
My fixture positions the punch well enough that I can go back and hit a second time, but I was unable to improve the result.

Here I used an arbor press to make the impressions.
IMG_3963
The right side of the “N” is not deep enough, and alignment is not very good.

So I will resort again to an engraving service.

Update 18 Jan 2013: Here, I believe, is the proper use of the punches: add serial number to an inside, hidden surface. I may settle on this and forego external marking that must be done at high quality.
IMG_4008
Note that the “1” here is a deeper impression than the other characters. It has a smaller total line length, and should therefore receive a lighter tap from the hammer.

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