Found this Today

I'll go out to the shop later and see the parts breakdown and I might be able to tell you exactly how to set it. I have a distributor's catalog of Mitutoyo instrument parts. It's not the newest stuff, but I believe it will have that mic in it.
 
Ok,

Last night before going to bed, I did a check on the mic against something I knew that would be a constant. And that was one of my Berger competition bullets. Berger is known for consistant quality control in their production of product. Lead cores are precisely cut and copper jackets are formed to exacting tolerances. My competition rifles are .223 caliber, which calls for a .224 dia bullet. The dia of centerfire .22 and rimfire .22 are different. Well so I pull out one of my 90 grain Berger .223 bullets and measure it. Now where you measure it is on the bearing surface of the bullet and the point on the bearing surface of the bullet is known as the pressure ridge. It is at this point that you would measure the dia of a bullet. Bullet makers run their product in lots and Berger puts the lot number on the box. This gives you a constant to go by. So I take that bullet and measured the pressure ridge with my electronic calipers. Now I know that I have checked my lil inexspensive calipers (14.95) against a Starrett caliper and mine was reading exactly .001 more than the Starrett. My measurement of the pressure ridge with the caliper was .2245. Then I did the same thing again and got the same measurement. So satisfied that I was doing the check consistantly enough I could use the Mitutoyo mic. What I came up with was .2236 with the mic, the way I did this was to bring stem down and rest on the pressure ridge of the bearing surface of the bullet, then watched the black needle on the lil windowed scale come to zero and then rotated the mic around to read which lines had lined up on the ten thou indicating lines. I did this three times and came up with the same number each time, .2236. So I am confidant enough that I feel that I can use the mic with reliable consistancy.

Here is a picture of a Barnes Bore Rider competition bullet, it is a .50BMG match bullet. It has three pronouce surfaces on it. If you look at the are of the bullet where the boat tail of the bullet meets the bearing surface of the bullet, you will see a pronouced ridge. This is the pressure ridge of the bullet. It's reason of life in a bullet is to seal the bore of the barrel so that the gases created will not escape around the bullet and reduce velocity.

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Well I played with the hand knurling tool.. ha, I will say this, it is a piece of junk, but I had fun with the experience since in reality, I got it for free. So, what is next for it, well it will become a donor to being something else somewhere down the line.
 
OakRidgeGuy said:
Well I played with the hand knurling tool.. ha, I will say this, it is a piece of junk, but I had fun with the experience since in reality, I got it for free. So, what is next for it, well it will become a donor to being something else somewhere down the line.
Click to expand...

That hand knurler is a fine tool, if the knurls are sharp, the frame isn't sprung and it's not wielded by someone hamfisted.
 
Ok..(trying to post this response for the 4th time!)

It will need new wheels.. as for what I plan on using it for in the future, I have a few ideas floating around in my head.
 
OakRidgeGuy said:
Ok..(trying to post this response for the 4th time!)

It will need new wheels.. as for what I plan on using it for in the future, I have a few ideas floating around in my head.
Click to expand...

A knurler such as the one you have wasn't meant to knurl heavy things. Brass tubing, aluminum tubing and very light knurling on steel. It's a 'gentlemans' tool. I still have two that belonged to my Dad. He bought them in the early thirties. They are unsurpassed for what they were made.
 
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