Suggest a micrometer

[Rocky Raab]

All that is true - but is also far overboard for anything you need to measure in reloading. Bullets fly, but they aren't the Space Shuttle.

[John Guedry]

I have a Midway caliper that I took out of its box the other day and the part that you adjust to get the reading literally fell apart in my hands. Like the metal disentegrated. I also use a harbor freight digital caliper and a Starret 0-1 mike. A shame about the Midway but what can you expect for $19.95?

[Shiloh]

I never heard of fixing up a micrometer. I thought that, unlike a mold, micrometer is a piece of precise mechanics, and any filing/polishing on the micrometer may not make it working better.

The barrel is adjustable for a zero, much in the same way as a caliper. That's as much as there is to be adjusted. If the engraved calibrations are off, you're
hosed.

Shiloh

[atr]

Lufkin micrometer and starett dial indicator....I find both very necessary

[machinisttx]

Mic's are nice to have, but for reloading, all you really need is a set of calipers. I've got a couple nice Starret and Mitutoyo calipers, but the ones in my reloading drawer are a set of stainless-steel Harbor Freight made in China calipers that seem to hold the same as my Starrets, and they were less than $10.

Would I use them for checking surface finish on aircraft parts? Probably not. But for measuring if my .357 bullets drop at .358 or .359, they are perfect.

You'd use a profilometer to check surface finish.

[Marvin S]

Jim has it right, just because it zeros dont mean its good. It could have worn threads in case of a used one or what is callled a drunken thread in case of a new one. Only you will know what is acceptable for you and most of them probalby be okay. For the cheaper ones I would look at the Fowlers.

[alamogunr]

Previous threads have discussed plug gages for measuring revolver throats. Why couldn't they be used to check accuracy of micrometers? I agree, if the threads are worn, zeroing against the anvil would not guarantee accuracy but checking several plug gage diameters should give an idea of repeatable accuracy. Just a thought and I may not know what I'm talking about.

John
W.TN

[machinisttx]

Previous threads have discussed plug gages for measuring revolver throats. Why couldn't they be used to check accuracy of micrometers? I agree, if the threads are worn, zeroing against the anvil would not guarantee accuracy but checking several plug gage diameters should give an idea of repeatable accuracy. Just a thought and I may not know what I'm talking about.

John
W.TN

Even with a properly calibrated mic, I have never been able to get the correct measurement on a gage pin...the mic will normally read a couple tenths under the actual size.

There is an adjustment that tightens the threads to allow for wear.

[alamogunr]

There is an adjustment that tightens the threads to allow for wear.

I was not aware of that. I got my micrometer when everyone wanted digital mics. Not having to use them regularly in my work, I was willing to take the old fashioned kind. Since they had an excess of them, I got to take it with me when I retired. It is a Brown & Sharpe. I guess I will have to read up on the adjustment.

John
W.TN

[ETG]

I guess I would have to ask why you would need .0001 accuracy on a reloading bench? A case could easily squeeze a bullet that much just seating it. If you are really concerned about cost go with the HF mic. I have checked mine on pin guages and they are the same as my mitutoyo's. Maybe not quite as smooth but very repeatable.

[Gerry N.]

I have a cheap Enco micrometer and a pretty good Mitutoyo. Both read the same when I measure things. The Enco cost about $6 on sale, the Mitutoyo was about $130. A cheap dial caliper costs about $20 anywhere tools are sold. Same for the cheap Chinese digitals. Look at 'em, they're all the same except for color of plastic on a few of 'em. All of 'em are good enough.

Too many people make perfect the enemy of good enough.

Gerry N.

[JIMinPHX]

Previous threads have discussed plug gages for measuring revolver throats. Why couldn't they be used to check accuracy of micrometers?

You can.

[JIMinPHX]

Even with a properly calibrated mic, I have never been able to get the correct measurement on a gage pin...the mic will normally read a couple tenths under the actual size.

Are you using the friction thimble? Is the thimble working correctly?

[Marvin S]

Even if the threads are worn, they are likely worn in a short area. So if you take the windage up there it will be to tight in the other areas. Just get a half way decent one with a vernier scale for .0001 places and it will most likely be accurate to .0005 depending on the user. I still stay away from the electronic just because I don't like to buy batteries.

[lwknight]

I was all about getting a Starret 0-1 when found the RCBS with digital side display for $59.00.
After examining it, I saw that it had the 1/10 vernier and standard markings on the barrel and thimble. The digital reader is just an easy quick reference, so if it failed I could still use it like any regular old mic. All-in-all its pretty good quality. Even comes with the wrench to adjust for calibration if necesary.
No one needs to read tenths for boolit casting but, if you are going to spend the money.
Why not go for something that will do it all the way. You might have other applications come up in the future where you wished that you had the tenths scale.

[machinisttx]

Are you using the friction thimble? Is the thimble working correctly?

I've used both ratchet and friction thimbles, mics properly calibrated and in perfect working order.

[JIMinPHX]

Even with a properly calibrated mic, I have never been able to get the correct measurement on a gage pin...the mic will normally read a couple tenths under the actual size.

How was the calibration done? Were the contact faces clean? Did you check to see if they were flat & parallel?

I'm not trying to break your chops here. I'm just asking the ABC questions out of the gate because I don't know what your background is. If asking these questions to you is like asking a cabinet maker if he knows what a biscuit cutter is for, then I apologize.

[machinisttx]

How was the calibration done? Were the contact faces clean? Did you check to see if they were flat & parallel?

I'm not trying to break your chops here. I'm just asking the ABC questions out of the gate because I don't know what your background is. If asking these questions to you is like asking a cabinet maker if he knows what a biscuit cutter is for, then I apologize.

My first job was in a toolroom making parts for both stamping dies and die cast molds. Typical tolerances were +/- .0002". I know how to use a mic. Any gage block measured was right, but when measuring round objects..especially small diameter ones...the contact area is so small that it's easy for the thimble and anvil to move a couple extra tenths.