Optical Center Punch

I finished up a project the other day manually. Ordinarily I CNC
everything, but I thought about it, and figured I could do most of what
I needed manually faster. I was making some die holders for some
Chinese pipe dies. All three dies in the set are a different OD. Sigh!
I CNC machined out some 1" 4140HT bar stock I had on hand to get the die
bore, clearance bore, and outside profile. The first one I CNC drilled
for set screws and handles, but that just seemed to be such a pain. 4
setups for each part to drill one lousy hole. Yeah, stops and fixed
vise jaw help speed that up a little, but still.
Then I told myself, this is silly. I used a dual beam height gage on my
surface plate and a calculator to determine all the measurements. Then
I just used a scribe on the height gage to make cross hairs in
cheapskate's layout fluid. (Sharpie Marker). This is not particularly
critical positioning. I decided to try out the optical center punch
setup my son had given me for Christmas last year. Every mark except
one was dead on the money. Even looking at them again under the optical
lens the punch marks were perfect circles equally divided by the layout
lines. The one that was off I felt slip as I brought the hammer down on
the punch. It was off maybe half a line width. I was able to push it
over by angling my spring punch. The same spring punch I used to deepen
the center marks before drilling. Then I drilled it all to size on the
cheap old HF drill press and tapped them by hand. I can use the same
handles on all three die holders, but I'll probably make handles for all
of them when I have time.
The optical center punch is not something I think I would have ever
bought for myself, but it sure does a good job for this sort of work.
Even an import from India.
Reply to
Bob La Londe
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Years ago to settle an argument I bet my boss that with a magnifier and a height gage with a sharp tip I could lay out and drill holes to within + or - .003". So he said sure. And I won the bet. Easlly. Eric
Reply to
I made mine. The lens isn't great, but works well enough.
Reply to
Pete Keillor

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