.060” Pin Punch (Sorry for the confusion)

Ulma Doctor

Ulma Doctor

Infinitely Curious
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I'm working on a project that had the smallest pin (.065”) that required extraction, luckily through holes are present for the pin.
i went to the toolbox and looked for my smallest pin punch, the closest i came was a .30"
obviously, that's a no-go.
i searched through the crap and found a 1/8"x3"unknownium pin that had an end broken off
due to the scale of the work i employed the Unimat SL1000
i used the stock 3J chuck and extended about 3/4"
after squaring the end, the diameter was reduced to .060” in steps to a length of approximately 11/16".
i relieved the tip to help stay on the split pin while driving
the end result was quite nice
have a look....

IMG_5520.jpg

as you can see the pin punch worked, the offending pin is pictured below the punch.

thanks for reading!

I screwed up in my previous post, this has been edited due to stupidity on my part
The drawing is incorrect, I measured incorrectly, placing an extra decimal point of resolution where it should not be.
My sincere apologies for my mistake .
 
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RJSakowski said:
Did you really mean 11/16"? It looks more like 1/16".
Click to expand...
Yes sir , i messed up.
the total protrusion from the big end is .068” the overall length to diameter is hard to scale by picture.
The real diameter is.060”
The pin at the bottom is.065”x 750”
 
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.006 is about as thick as 2 pieces of paper.
I wouldn't even be able to see a pin that small.
 
I'm not understanding something here. If the punch is .125" diameter in the 'handle" portion, the the punch end would be about 1/20th that diameter. It appears larger than that.
 
john.oliver35 said:
I'm not understanding something here. If the punch is .125" diameter in the 'handle" portion, the the punch end would be about 1/20th that diameter. It appears larger than that.
Click to expand...
Very astute, you made me recheck my measurements. I’m very sorry to inform that I have been foolish.
I have edited the post to reflect my mistake.
My apologies and thanks go to you.
 
Ulma Doctor said:
Very astute, you made me recheck my measurements. I’m very sorry to inform that I have been foolish.
I have edited the post to reflect my mistake.
My apologies and thanks go to you.
Click to expand...
That's kind of what I was hinting at with the thickness of paper comment.
For reference, .030 is the thickness of a credit card so I suspect that the punch you mentioned in the OP was .300

Easy to make that mistake when typing dimensions.
 
Even so, turning an 11/16" long .060" pin is a notable achievement. Some twenty plus years ago, I made some 10cm long pins, 2mm in diameter from an epoxy composite for a new product prototype. Used the same procedure that you have described. I was using a 12" Craftsman lathe at the time and it had some runout so there were slight discontinuities at each of the steps it the result was good enough to demonstrate proof of concept. To prevent the turned pins from bending and breaking, I mounted a tube in the tailstock to receive the turned pin. It was a loose fit but sufficient to prevent the pin from running out more than a few thousandths.

Some ten years later, on a different product, an outside vendor was making 10cm long shafts 2mm in diameter on a Swiss screw machine using essentially the same strategy. As I recall,his raw material was 1/4" 304 stainless and his product was flawless, both dimensionally and in surface finish. AFAIK, he is still making those pins in production for the company that I worked for.

Joe Pieczynski has a You Tube video where he turns a small diameter pin effectively using this same technique.
 
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