Micrometer purchase

[hc18flyer]

A few weeks ago I borrowed a friend's micrometer to check my Dillon powder thru expander. I ended up ordering a new one for my button nose wad cutters in .38 Special. I found my 'cheaper' digital caliper wasn't as accurate as I thought. I had also read some posts that the Lee 'push thru' sizers might be undersized? So I found an economical micrometer, with good reviews on Amazon. Today I checked several of my .38 Special and .45 Colt bullets. No surprises on RCBS or Lee sized bullets. I think it will be beneficial checking my taper crimps too. hc18flyer

[HWooldridge]

You might also want to buy one or two Class XX ground gage pins to check calibration periodically. A .2500 and a .5000 pin would cover the common range for most calibers, and ensure your mike is properly set.

[Mk42gunner]

I've never had a digital caliper, but have had a couple of Harbor Fright dial calipers. They are accurate enough for most of my reloading needs, until they aren't. Then the old Tumico Scherer (sp) or Brown and Sharpe micrometer comes out.

My ball ended micrometer is labelled Lyman, but I am quite sure it was made in Asia. I only use it to measure case mouth thickness.

Robert

[country gent]

A nice addition to the mikes is a set of small hole gauges for measuring IDs.

I can remember when most shops would allow dial calipers for any close dimension

[DougGuy]

A few weeks ago I borrowed a friend's micrometer to check my Dillon powder thru expander. I ended up ordering a new one for my button nose wad cutters in .38 Special. I found my 'cheaper' digital caliper wasn't as accurate as I thought. I had also read some posts that the Lee 'push thru' sizers might be undersized? So I found an economical micrometer, with good reviews on Amazon. Today I checked several of my .38 Special and .45 Colt bullets. No surprises on RCBS or Lee sized bullets. I think it will be beneficial checking my taper crimps too. hc18flyer

What would be a great help is a micrometer stand. It holds the micrometer and lets you have both hands free, one hand to hold the boolit between the anvils, turning as necessary to measure different parts, and the other hand to turn the friction stop to adjust the mic.

[country gent]

The proper hold or grip is important to using a mic also.
Roll the little finger inside the frame and press it against the ball of the hand turning the thimble with the thumb and fore finger. with bigger mics you may need 2 fingers inside the frame.

At one shop I worked a micrometer stand was one of the apprentice projects they could opt to make. Its an nice project

[uscra112]

You might also want to buy one or two Class XX ground gage pins to check calibration periodically. A .2500 and a .5000 pin would cover the common range for most calibers, and ensure your mike is properly set.

AMEN! But don't pick even numbers. Chose .2465 and .5012 for example.

[M-Tecs]

0-1 Mics normally are zeroed by cleaning the anvil and the spindle face by pulling a clean piece of printer paper thru them. Gage pins close to the size of the part you are measuring ensures that you have the proper feel even with the ratchet or friction thimble.

Class XX are good for calibration. The common and cheap Class ZZ .0002″ tolerance really aren't accurate enough.

https://www.meyergage.com/abcs-of-ga...nce%20chart%29

https://www.machinistguides.com/ulti...d.800%E2%80%9D.

[hc18flyer]

Thanks for the suggestions. I will have to add to my 'wish list'! I may try to make up a simple stand? hc18flyer

[DougGuy]

AMEN! But don't pick even numbers. Chose .2465 and .5012 for example.

Pick calibers that actually fit what you are going to work with. .311" .3135" .3585" .4115" .4315" .4525" .478" And you want ZZ minus (-.0002") pins. Your mic will read the actual diameter of the pin, not what is laser marked on it. Your mic will read -.0002" than the pin is marked. Right there is all the calibrating your mic will need.

For measuring gun cylinders you always want a tool (gage pin) smaller than the hole. A pin that's the same size as the hole you are measuring, won't go in the hole.

The common and cheap Class ZZ .0002″ tolerance really aren't accurate enough.

ZZ minus class doesn't mean + or - .0002" of tolerance, like slop is permitted, it means the pin is intentionally ground to be .0002" smaller than the diameter marked on it. They are equally as accurate as any other ZZ pin.

[M-Tecs]

Thanks for the suggestions. I will have to add to my 'wish list'! I may try to make up a simple stand? hc18flyer

Cheap stands start at about $15 on amazon. That being said county gents advise about proper holding a mic aids in accuracy and proper feel.

https://www.fullyinstrumented.com/ho...se-micrometer/

[William Yanda]

AMEN! But don't pick even numbers. Chose .2465 and .5012 for example.

I am not a machinist. Help me understand why. Thanks. Bill

[MrWolf]

Cheap stands start at about $15 on amazon. That being said county gents advise about proper holding a mic aids in accuracy and proper feel.

https://www.fullyinstrumented.com/ho...se-micrometer/

If you have a 3d printer, there are free files to print one. Might need a small piece of metal to serve as a counter weight to prevent tipping.

[HWooldridge]

I am not a machinist. Help me understand why. Thanks. Bill

A pin gage of known size provides a solid comparison point to check your mike or caliper, to ensure it is accurate and repeatable. Where I work, we check calibration with .1250, .2500, .5000, .7500 and 1.000 Class XX ceramic pins - and the pins are sent out every two years to a certified lab to verify they are not wearing out. What this does is provide a scale to let the calibration technician observe whether any wear is occurring in the instrument. We have about 1,200 instruments of various types in the factory which are in daily use and moving parts do wear out. I seriously doubt the average individual will wear out a quality instrument in his/her lifetime, unless it is used all the time. My first Mitutoyo digital 0-1" micrometer finally gave up the ghost on its electronic display but the actual mechanics were still in good shape.

[beemer]

I have several dial calipers laying around. A Harbor Freight is laying on my bench. I don't leave my good set laying around. Guess I was lucky, when checked against a Starrett caliper and 1" calibration gage and it was right on. Don't remember the brand but I got a tubing mic off Amazon, figured if it was off at least it would show any variation. When checked against feeler gages and other mics it was very close.

I keep an eye out at estate sales, flea markets, and junk stores. Bought a very nice set of Starrett calipers in box for $10 and a set of Mitutoya for $3. Have also found several Starrett and B&S mics cheap. My brother gave me a set of vernier calipers, very nice and marked with the Mauser Banner. Takes me a bit but I can read them.

I have been eyeing those mic stands for a while, guess next order will I will get one.

[country gent]

Pins in the right steps or blocks will not only show if the mics are calibrated but if the faces are square and parallel to each other.You want to check at every 1/2 turn or 1/4 turn. The face wear is normally present on older mics or mics used in a production environment. The other check is every .200-.250 IE .22,.400.600,.800, and 1". This will show thread wear again more important in mics in a production environment where they are used in a narrow range for years. A lot of plants rotate measuring tools thru different jobs to keep wear even.
Most mics have a collet on the threads to take up wear over the years. But a mic that has always been used at a certain size will have a low spot there and full threads almost everywhere else Adjusting to the low spot leaves it tight on each end.

The best thing for you mics is simple a drop of instrument oil every so often. Instrument oil doesnt gum or thicken its the right viscosity to provide the film with out affecting "feel". That drop of oil will greatly extend the life of tools.

[Green Frog]

I'm a veritable machine shop dilettante, but I remember one of my instructors commenting that a dial caliper was a "little better" than a yardstick, "but not much". I've never been able to stir up any enthusiasm for digital calipers or micrometers, at least those I could afford, so I've gathered up used Starrett micrometers, old enough to be good ones, and Mitotuyo dial calipers, and allow them to define "Degree of Frog" accuracy.

Forge

[Three44s]

I'm a veritable machine shop dilettante, but I remember one of my instructors commenting that a dial caliper was a "little better" than a yardstick, "but not much". I've never been able to stir up any enthusiasm for digital calipers or micrometers, at least those I could afford, so I've gathered up used Starrett micrometers, old enough to be good ones, and Mitotuyo dial calipers, and allow them to define "Degree of Frog" accuracy.

Forge

I have always figured that if I could measure within a "frog hair or two", that I would land my rounds on a squirrels head at 2 hundred pretty consistently.



Three44s

[georgerkahn]

I had challenges with a Lipsey/Ruger .45 Colt revolver I sent to DougGuy for his magic and, in discussion with him, he suggested a micrometer he uses. I found one of exact same model and have ZERO regrets vis its purchase. I have both a Starrett and a Brown & Sharp micrometers which are high quality and -- when checked on pin gauges -- are "right on!". But -- with further appreciation to DougGuy -- buying the "Mitutoyo 193-211 Digit Outside Micrometer, Inch, Friction Thimble, 0-1" was without a doubt, one of my best purchases. So quick and easy to use, with almost guaranteed 100% repeatability of measurements.

[Froogal]

I've never had a digital caliper, but have had a couple of Harbor Fright dial calipers. They are accurate enough for most of my reloading needs, until they aren't. Then the old Tumico Scherer (sp) or Brown and Sharpe micrometer comes out.

My ball ended micrometer is labelled Lyman, but I am quite sure it was made in Asia. I only use it to measure case mouth thickness.

Robert

I own a set of Hodgdon dial calipers. I also own a set of Tumico-scherer dial calipers. The Tumico is smoother operating, but there is no difference in accuracy between the Hodgdon and the Tumicos.