Ball Micrometer

adamsgt said:
that Butch is being a little "tongue in cheek"? I have noticed , as I'm sure most of you do, that I can vary the reading depending on how much pressure I put on the thimble. Thus it can be easy to "get the reading you want".
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You are correct Jerry.
 
I realized Butch was joking. I have seen micrometers abused in about every possible way, the use
as a clamp was one of the worst. I have also seen people force a preset mic over a shaft, 4 to 8 in dia.
to prove the length of the shaft was totally true. People never cease to amaze me in their abuse of fine
tools.
 
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Brian Adams said:
Bump



Did you ever find a ready made depth stop solution for using the ball micrometer?

(Advising someone to just turn the case necks, then measure loaded rounds' necks, misses the common use for a ball mic - to determine what you have in hand before neck turning. A depth stop is an obvious need since most factory case neck walls are progressively thinner between shoulder junction and case mouth.)
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No. Continued my method of measuring the OD of the loaded round. Keeping it simple. :)
 
where

Where is the correct place to measure a case ? I noticed they are thicker as you move deeper into the case.
 
I measure a few points on the neck, starting midway down:

Tube_Micrometer.jpg


-Lee
www.singleactions.com
 
Brian

I guess I've forgotten - as I have so many things. Catch me up please Sir. Why would I care what the original neck measured if my intent was to turn the neck true...and to fit an undersized chamber?

Having a "depth stop" is really important when you're measuring bullet jacket wall thickness. You can have one made if you need one. Frankly, there was a "lot" of bullet jackets that varied quite a bit and I sent them back. Turns out that they were record setting jackets! No, I wasn't wrong in my measurement. The jackets were terribly poor (by the standard of the day) but made EXCELLENT bullets. Go figure!
 
Wilbur said:
Having a "depth stop" is really important when you're measuring bullet jacket wall thickness. You can have one made if you need one.
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I finally made my own, out of a short section of hardwood dowel. Made the plug the height I wanted, drilled a 5/32" hole in the middle (happened to fit the shaft where it would go perfectly) then I used an Xacto knife and a small mallet, rapping on the back of the blade, to split it along the grain through the hole, and glued the two halves back together, around the shaft, using thin super glue. It's permanently in place, but will be easy to split apart and remove some day. I can slide it up and down to change the height, and I made a couple of shims out of plastic bread bag clips to wedge under it.
 
Wilbur said:
Catch me up please Sir. Why would I care what the original neck measured if my intent was to turn the neck true...and to fit an undersized chamber?
Click to expand...

Sorry, missed your question until now:

I don't turn necks, I sort factory brass and cull out those with a lot of neck thickness variation.

Un-turned necks seem to have walls the get progressively thicker towards the shoulder, so a depth stop is obviously required in that case.

But a stop I think is handy even with turned necks, it supports the case and allows you to concentrate more on operating the mic and less on holding the case.
 
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