Micrometer Questions?

[mjwcaster]

So I am searching for a micrometer to buy.
I have read all the posts I can find here on it.

I plan on sticking to older US made mics.
Searching ebay and trying to research is making my head hurt, but what is the point of upgrading from calipers unless I get something better and then learn how to use it.

Can I use pin gauges as makeshift standards?
I plan on buying some any way, and figure something to check the middle of the range where I will be working on is a decent idea.

What should I look for besides brand?

What is the difference between a Starrett 230 and 436?

I see the 236 comes in .001 and .0001 models, no way to tell besides seeing the markings on the mics itself?
Or are there differences and the starrett site just uses some of the same pictures?

And does it make a difference for a beginner- friction or ratchet type?

And does any of this matter in regards to older 230's, is it just the new ones that have a dizzying array of choices?
What I don't get is on the new ones there is virtually no difference in price for the greater accuracy?
Why wouldn't you just but the better one for $10 more?

I know I am making this more complicated than it needs to be, but in a sick way I enjoy learning all about these things.


The more I research the more questions I get, and I haven't even started researching the other brands yet.

[bbqncigars]

All you need is a resolution of .001" for reloading. Starrett and Mitutoyo are good, but know used mikes can have a history of abuse. My chinese Lyman mike is decent enough for the job. YMMV

[mjwcaster]

I should also mention that one of my dreams is to take some shop classes, learn how to measure stuff, sharpen things and run a lathe and mill.

I can see collecting mics and others measuring tools, use the best ones for machining and the lesser ones stay on the reloading bench.

[jmorris]

Friction or ratchet type keep the operator from turning them into a C clamp.

If you have standards for them you can learn to use both properly.

Once you get over 6" accuracy is questionable to the ten thousandth of an inch, with either type but again standards help you get a "feel" for the instrument.

[Ballistics in Scotland]

One of the annoying things about eBay is that some micrometers are sold by people who don't know that they come in .001in. and .0001in. persuasions, and can't tell the difference. You have to rely on the pictures, if they are clear enough, or find the information on the manufacturer's website.

Yes, you can use a pin gauge like a micrometer standard - diameter, of course, since they aren't held to a precise length. Bear in mind, though, that pin gauges are made to different tolerances, which you should be told on the box. The commonest is the type in which the manufacturing tolerance is all under the nominal diameter, so that a nominal .30 gauge is sure to enter a true .30 hole or gap.

People frequently assume that a micrometer must be accurate when the anvil makes light contact and the graduations read zero. But this isn't necessarily the case. There is a little hole in the sleeve to let you adjust the reading by rotating the sleeve it with the wrench provided. The usual standard is large, e.g. 1in. for a 1in. micrometer, and therefore checks it at an end of the scale you rarely use. For the reloader, a pin gauge of .30in. or so may give a more useful assessment for the tasks you will actually use it for.

The .001 micrometer is adequate for virtually all gunsmith and reloading tasks. If you were making bullet swaging dies, .0001 would be worth having. But anyway, what is .0001in. accuracy? If a micrometer is only capable of an accuracy of .0002in. across its range, due either to manufacturing quality or wear, that is what you get, regardless of the graduations and lines engraved on it. $10 seems plenty for engraving.

[oldred]

Also the are the digital mics, personally I just don't care for digital, even for calipers, but others may see things differently. I suppose the digital mics are accurate enough (at least the "name brands") but I was constantly finding myself chasing that last number when it wasn't even necessary but all-in-all they must have something going for them because a lot of people surely do like them!

[Beagle333]

Just pick you up one of these, a 1" Starrett 436 with the little knob on the end, that looks similar to this one, for around $25-30± shipped and you'll be good.
http://www.ebay.com/itm/Starrett-No-...item259e8601fa

[EDG]

The #1 Brown and Sharpe chrome framed mikes can often be bought for $12 to $15.
I am talking about a mike with chromed frame, .0001 verneir, a friction thimble and carbide faces. Older B&S mikes that have been rode hard are usually no bargain.

I can show you what to look for on Ebay.
There are plenty of good mikes there.
You are normally looking for a like new 20 to 40 year old mike.

The more expensive Starretts are ok. Starrett made a heavy duty mike that was really good but they are usually very expensive. I don't much like the painted frame mikes. Many of the older cheaper Starretts and Brown and Sharpes do not have .0001 or carbide faces. I loathe steel faces on a mike.
Starretts have a lot of brand loyal types out there and they are often bid up higher than their level of quality is worth.
For the most part Starrett is just an ordinary mike.

The Japanese Mitutoyo mikes are excellent too and they all have carbide.
Lufkins with carbide are very, very good.
Other good brands are Scherr-Tumico (also sold by Sears as Craftsman)

On the super duper end are the fat barrel Swiss made Etalons that you can read the tenths more easily.
The German made Mahr is sort of the Rolex of mikes.


There are dozens of good mikes on Ebay each month. It is easy to find a real bargain.
There are so many in fact that all you have to do is pick a model you prefer. Set a auto notification to email you and wait until a good one shows up. If you do not win the bid - no big deal. Another mike will soon come along.

Bear in mind many people have open selling accounts on ebay and they are happy to over price anything they have whether it is good or bad. What you are looking for is an excellent mike for $20 or less plus shipping. I get bored and rescue a nice mike from time to time. My last one cost me $12 plus $5 shipping

I would be glad to show you what to look for.

[Ballistics in Scotland]

I have a couple of the cheap Chinese digital calipers, and they seem accurate, though I wouldn't be surprised if they don't last. I would call them well worth having at the price, for they will do a lot that a small mechanical micrometer can't. Yes, you can buy micrometers of 4 or 6 inch capacity, and internal micrometers, depth micrometers, blade micrometers etc. But the average amateur gunsmith simply won't.

A ball micrometer is useful sometimes for measuring the minimum distance between concave surfaces, but is rarely worth buying. There is an accessory, though, which holds a hard steel ball against one or both surfaces of the micrometer, and this is usually cheap. Usually the ball is 0.1in. in diameter, so you just deduct that from the reading on a general-purpose micrometer.

[fast ronnie]

What size mic are you looking for? I have a couple in the shop that I don't use. They are Starretts but don't know whether 1/10's without going out to look at them. I have two sets of B&S 1-3's I have been using for nearly 50 years. Periodically, I check them for zero. but have not had to adjust them for years, and I use them nearly every single day in the shop. Over the years, I have used many different precision tools, and like others, I have my favorites. #1 in my book are B&S, although my 3" to 12" set is a mixed bag of Starrett 436's, and yes, they come in different styles in the same model. The last time I bought new Starrett, I was disappointed in their quality and a couple pieces were so bad they were returned for replacement. (they did replace without questions other than what the problem was.) On the other hand, I have a set of Starrett dial calipers bought new in 1970. They are the most accurate of any of the five sets of calipers I have except the B&S which are equally accurate, (no better or worse but do feel different.) Mitutoyo's are iffy. I have two sets of which one is probably 25 years old, and are very accurate. The other set is 5 or 6 years old and were bought when I dropped my Starrett's and broke them, and had to wait for the Starrett's to be repaired. Those are a whole 'nother story. I don't trust those things to any closer than .005 thousandths. (not .0005, I mean literally 5 thou.) I can check tomorrow and see what those two starrett's are as I don't use them. I believe there is a 0-1 and a 1-2, but as i recall, they are not in tenth's. If interested, PM me, and I will check the condition and let you know. You can also buy new pretty reasonably at Discount Machine sales, or MSCDIRECT, both of which have good web sites and are great to deal with. I have had an account with MSC for years, and they have extremely good service. If it's in the cataloge, it's in stock and I have it the next day without having to pay extra charges from getting stock from one of their other warehouses. Enco may be cheaper, but they don't have the selection, and some of their stuff is?????????
Because you are in Illinois, you could also call Tri-State Instrument in Fort Wayne, Indiana. When I lived there, they had pretty good service, too. I purchased quite a few tools from them back 40 years or so. By the way, any mike over 1" comes with a standard to check them. At least that's been my experience, but I haven't bought a new set of mic's for at least 30 years, so don't know what today's practice is.

[coleman]

On starretts mics if it don't have Athol Mass USA stamped on the thimble, It is not made in the USA and are ****, The steel is soft and they are trying to maximize profit outsorcing to 3rd world country. I use to be a die hard Starrett guy, all my tools are starrett usa I don't advise starrett anymore if its not made in usa.

[Dhammer]

You can usally find better deals on Craig'st list and get to handle them first before buying. I've paid $10.00 for a set of 4 US mics.

[cuzinbruce]

I have several Brown & Sharpe mikes and like them. Look for the carbide faces. A standard is nice but I rarely use one. I set a mike at the desired case length and use it check case lengths. And overall length on loaded ammo. Calipers are very handy for longer things, vernier are good, dial are easier to read. Good combo would be a 1" mike and a 6" caliper. That would take care of most of the measurements you have to do reloading.

[zuke]

Gauge block's and drill rod make good standard's.

[Ballistics in Scotland]

On starretts mics if it don't have Athol Mass USA stamped on the thimble, It is not made in the USA and are ****, The steel is soft and they are trying to maximize profit outsorcing to 3rd world country. I use to be a die hard Starrett guy, all my tools are starrett usa I don't advise starrett anymore if its not made in usa.

Oh, these aren't at all bad. But Moore and Wright, long-term manufacturers of extremely good micrometers in the UK, have gone exactly the same way on imports. If they didn't, people would just buy them from the A.N. Other Importing Company.


Attachment 129585

[lightman]

I have a stainless Craftman that I bought at a gun show for $10. I used feeler gauges to practice on, as there is a learning curve. Thanks to this thread, I now know who made it.

[257]

around here you can find good used 0-1 mics for 10.00 at flea markets 25.00 here would get you a starrett that would look like new with the box.

[bedbugbilly]

I can't add anything to what has already been said . . . other than I applaud the OP for his "thirst" for knowledge on not only the micrometer but machining as well.

Many, MANY years ago my major was metal working and I graduated from one of the leading colleges in training Industrial Art instructors. I taught shop and before any student even learned how to turn a lathe or mill on, they knew how to measure, use a micrometer and more importantly, if they didn't know something, how to look it up in the Machinists Handbook. In my training, I had one 4 semester hour (college) class on nothing but the Machinist's Handbook - and if you wanted a passing grade, you'd better know it from the front cover to the back (and you machinists know how thick that book is)!

Unfortunately, this country has gone through the cycle again where students in junior and high school no longer have Industrial Arts classes in which to be exposed to such things. Very few IA programs are left at all - regardless of if it is metal working or wood working, etc. If they want it, they have to get it through trade schools, apprenticeships, etc. In college, I learned on lend/lease surplus equipment from WWII - LeBlondes, Bridgeports, etc. - NC was just a "futuristic concept" at the time. There was nobody I had any greater respect for than the tool and die makers and machinists that I later encountered as I worked out in industry doing design work - and from them, I learned even more.

mjwcaster . . . the best of luck to you in finding the micrometer that you want - you'll locate one. And, I encourage you to follow your desire to learn more about machining, etc. and take classes where you can get good "hands on" experiences with the various machine tools. The knowledge is something that will serve you well in a wide variety of areas. Good luck!

[big bore 99]

I am a retired tool maker and was in the trade for 49 years. I always used Starrett tools, but Brown and Sharpe, Lufkin, and most of the imports are good too.
I never used the ones with digital read outs or friction thimbles. .0001 read outs on the thimble and carbide faces are all I've used. Get one and practice with getting the feel for it. I don't believe you even need .0001 for reloading work. You can very easily read .0005 on the barrel.

[MtGun44]

In order to actually GET .001 accuracy, the mic needs to be capable of greater
accuracy. I worked for an aerospace company for decades that made weapons system
components and our manufacturing requirement was that the measuring
system MUST be able to resolve 1/4th of the desired accuracy. If you want
to control a dimension to 0.001, you need to be able to measure to .00025
or better for your measurement to be meaningful.

This is why you need a .0001 mic to measure boolits to (AT LEAST) .001, and
.0005 is better, and still meets the 1/4th requirement.

Bill