Gunsmithing Point Anvil Tipped Micrometers for Measuring Bore Slugs?

[MtnGhost]

Not sure if this is the right section to post this, but I need to buy a new set of mics that I plan to use exclusively for measuring bore slugs / bore casts and ammo. I've had some issues with my old flat tipped mics, so I'm thinking chisel tipped or pointed tipped (15 or 30 deg) would be a good option, especially for really small bores where it's hard to indicate off the land indentations of the bore diameter.

On the other hand, I switched to Cerrosafe from the harder lead alloy that I was using prior, so I'm concerned that using really pointy tipped anvils could indent the slugs (or soft lead ammo) and give me bad readings.

Wondering if anyone can chime in and let me know if I'm being too paranoid or if there's a better option that I should be looking at. Thanks in advance!

 

[12Bravo20]

What you seek is a screw thread comparator micrometer. Be warned, they are not cheap. A Starrett thread comparator micrometer is around $200 to $220.

https://www.starrett.com/metrology/product-detail/210AP

 

[E. Bryant]

Here's an option:

McMaster-Carr

McMaster-Carr is the complete source for your plant with over 595,000 products. 98% of products ordered ship from stock and deliver same or next day.

www.mcmaster.com

Note that most of these are sold individually, not in pairs.

 

[MtnGhost]

What you seek is a screw thread comparator micrometer. Be warned, they are not cheap. A Starrett thread comparator micrometer is around $200 to $220.

https://www.starrett.com/metrology/product-detail/210AP

Thanks! I wanted to get two sets of mikes for under a grand. I was given an excellent quote on a set of higher resolution Mitutoyos, so I was planning to set up the high res set in a fixture and have a second set that I can float around.

Here's an option:

McMaster-Carr

McMaster-Carr is the complete source for your plant with over 595,000 products. 98% of products ordered ship from stock and deliver same or next day.

www.mcmaster.com

Note that most of these are sold individually, not in pairs.

Thanks! I never knew they made those in rubber. I wonder if those would work better with a friction thimble? Adding some of those to my next MC order none the less!

 

[12Bravo20]

I have had my Starrett thread comparator micrometer since 1996 and it definitely has came in handy over the years as a tool and die maker/machinist and with other uses too.

The Starrett 210AP is actually a decent price once you start comparing them to other brands or even Starrett's digital readout version.

Most shops I worked at did not have actual thread micrometers due to the price so we always just used the three wire method to measure threads.

I have used the slip on points and they just aren't as accurate. But I was dealing with tight tolerances with machines and tooling too.