Which outside micrometer? (Mitutoyo, probably)

[Samuel D]

There are times I’d like to measure something with greater precision than my Mitutoyo 530-101 vernier calliper allows (graduation 0.05 mm, accuracy ±0.05 mm). For example, the thickness of a shim.

Mitutoyo lists hundreds of micrometer models in this PDF:

https://www.mitutoyo.eu/application/files/9415/5888/6605/Micrometers.pdf

Where do I start?

I don’t want to spend more than necessary on luxury, but I want something that works well and lasts – hence my interest in Mitutoyo whose entry-level vernier calliper has served me well for nine years and counting. But tell me if I should look elsewhere.

I see some models have different graduation (0.01 mm versus 0.001 mm) but the same accuracy (e.g. ±2 µm). Why?

Not sure I need a model with a constant-force device, but you tell me.

Do I need a standard too?

Thanks.

 

[davethorik]

I am not familiar with Mitutoyo model #s, but just get a basic bluish green enamel frame 0-25 analog. Get carbide faces. Almost every machine shop in the area I've seen uses the basic Mitutoyo mics in 0-6" or 0-12" sets as "shop mics", they hold up well in shop use.

I like digital calipers but not digital mics. Too bulky.

The extra division is probably similar to the 10,000th inch vernier scale on some inch mics, I have never used a metric mic with one so i am guessing. You probably do not need the extra accuracy for general use, and when you are getting that small, you need a temperature regulated environment.
.001mm is .000039" holy ****.

Friction or ratchet or plain thimble is a personal preference. When I began using mics i liked ratchets. Now, i prefer plain, so you can get a good feel. But that is just me.

 

[Samuel D]

What’s the difference between ratchet, plain, and thimble? Especially the meaning of the word thimble wasn’t clear from the Mitutoyo website.

Doesn’t the appropriate force depend on the object being measured? Measuring the diameter of a cylinder would require less force than measuring the thickness of a shim. Measuring the diameter of a ball would require even less force (almost none, I guess). So can the constant-force device be adjusted?

If it matters, I think I have a fairly good mechanical feel and understanding (for a hobbyist mechanic, not for an experienced machinist I’m sure).

 

[Dave455]

O.k. First decide if you want electronic or mechanical. I personally would go for mechanical. There’s nothing really to go wrong and it should last you a lifetime.

I assume the .001 have an extra vernier scale. If you want it, fine, but as Dave pointed out above, that’s an incredibly small amount. Personally I reckon .01 is fine!

The ‘constant force’ device can be useful, especially if you are not used to micrometers. All of mine have come with some sort of ratchet or sliding sleeves as standard. I can’t recall what Mitutoyo offer, but it will probably work fine.

You only need a setting standard if the micrometer doesn’t read from zero. If you have a 0-25mm mic, you close it up to set it to zero. On a 25-50, you will need a 25mm standard to do the same thing.

Mitutoyo mics are fine, but I would look at how much a Tesa (Swiss) would cost you. I think they’re nicer. If you are buying bigger mics, consider used. There are huge savings to be made, and there’s not much to go wrong with a micrometer. Buy any decent make used - Mitutoyo, Tesa, Moore and Wright, or Starrett!

 

[Dave455]

What’s the difference between ratchet, plain, and thimble? Especially the meaning of the word thimble wasn’t clear from the Mitutoyo website.

The thimble is the part of the sleeve that you grip with your fingers to use the micrometer.

A plain thimble is just knurled (rough) do you can grip it, nothing more.

A friction thimble is just an extra sleeve over the top that turns the actual sleeve by friction.

A ratchet is usually an extra little knob on the end of the sleeve. If you decide to use it, it ratchets above a certain torque.

 

[davethorik]

Here is a model i would suggest.

Mitutoyo 103-137

 

[Dave455]

What’s the difference between ratchet, plain, and thimble? Especially the meaning of the word thimble wasn’t clear from the Mitutoyo website.

Here are a couple of pictures that show the difference. The black micrometer, a Moore and Wright, has a ratchet. It’s the extra bit on the far right hand side.

The grey one, a Tesa, has a friction thimble!

 

[Samuel D]

You only need a setting standard if the micrometer doesn’t read from zero. If you have a 0-25mm mic, you close it up to set it to zero. On a 25-50, you will need a 25mm standard to do the same thing.

I see. That makes sense.

If you are buying bigger mics, consider used. There are huge savings to be made, and there’s not much to go wrong with a micrometer. Buy any decent make used - Mitutoyo, Tesa, Moore and Wright, or Starrett!

Is Roch any good? There are a fair few used models for sale around the Paris area (where I live). Examples:

https://www.leboncoin.fr/outillage_materiaux_2nd_oeuvre/1770786381.htm/
https://www.leboncoin.fr/outillage_materiaux_2nd_oeuvre/1788346245.htm/

Worth a gamble or definitely not for a buyer who doesn’t know what they’re doing?

Here is a model i would suggest.

Mitutoyo 103-137

Yeah, looks like a solid choice from what I’ve read in the last couple of hours.

Thanks for the photos, Dave455.

 

[mowkep]

I have a Starrett 0-1 w/mechanical digital readout on it for sale in the classifieds. Would help you with metric or standard reading

 

[Dave455]

I see. That makes sense.


Is Roch any good? There are a fair few used models for sale around the Paris area (where I live). Examples:

Yes, I think so.

I have only seen a couple of examples but they were very nicely made. Certainly up there with the makes previously mentioned.

You might find the older ones are harder to read, but that’s common across all makers.

The examples shown look quite nice, but those prices are a little high compared to U.K. prices. I can usually get a very nice 0 to 1 inch mic for the equivalent of about €20 Maybe pay a little more for metric, but not much.

 

[seber]

Unless you are a very careful person, I would stay away from digital mics. We provided digital mics to the workers on the floor as they could not be trusted to read a vernier properly. It was a constant headache for the repair station trying to keep them functional. They tried both mechanical and electronic. The electronic option went away pretty fast. Once one of those went wonky, there was no coming back.

 

[Samuel D]

Here’s a cheaper Etalon, but it has a touch of rust on the screws:

https://www.leboncoin.fr/bricolage/1625479909.htm/

I don’t suppose the rust on the screw heads matters, but maybe it indicates rust elsewhere, like the main screw or faces. The plastic case suggests that was not as expensive to buy new as the Roch models with the beautiful wooden boxes and certificates. And the ad has been online since January, possibly a warning sign.

I have a Starter 0-1 w/mechanical digital readout on it for sale in the classifieds. Would help you with metric or standard reading

Thanks, but I live in France (shipping, import duties) and only need metric.

Think I’ll just get the new entry-level Mitutoyo and be done with this.

 

[Samuel D]

Unless you are a very careful person, I would stay away from digital mics.

I have no interest in digital versions. I’m only likely to measure a handful of things in a day, so speed of reading is not a concern. Durability is: I’m still in my thirties and want this to last me out. Low cost is important, too. I don’t want to worry about flat batteries or leakage. And I just flat-out prefer mechanical things. Where electronics make a large functional improvement (e.g. fuel injection), I tolerate them. Otherwise, I prefer to avoid them.

 

[matt_i]

On the solid vs. ratchet thimble it was explained to me like this:

If you are a toolmaker/machinist then you want a plain direct drive thimble as you will develop the feel for mic-ing things. Can practice on standards/gage blocks/drill rod, etc.

If its a mic used by a production worker, possibly different workers rotating thru jobs or shifts then the ratchet thimble is best because it will allow a more repeatable measurement when used by different hands. And the precision leadscrew inside theoretically can't be damaged by aggressive tightening. So maybe we should say "less likely to be damaged by aggressive tightening"

 

[kapster]

I'm a machinist for a living, can't go wrong with Mitutoyo. I would stick with their entry level blue enamel version as pictured above.

Definitely get a ratchet or friction thimble. I really like the Mitutoyo ratchet, never cared for friction. Some brands ratchets are to tight, Mitutoyo is right on and applies an appropriate amount of force on the anvil.

Definitely get a lock and carbide faces.

I would get as fine of graduation as they make, I'm not real familiar with metric mics but the finer graduation is likely an extra vernier scale on the side. If they're like .0001 graduation inch mics, they cost little extra and don't get in the way but they're there if you need them.

I also have Mitutoyo digital quantumikes. I love em but I only use them when I need the fast reading precision like dialing out taper on an OD grinder. To bulky for everyday is imo. If cared for, the standard mechanical Mitutoyo will last you several lifetimes.

Sent from my moto g(6) using Tapatalk

 

[Downwindtracker 2]

My metric mics are Polish VIS 0-75mm, a Japanese Kanon 75-100 and a Japanese, not Brazilian, Mitutoyo 100-125.

The VIS are friction thimbles, they use a spring. They came from the factory with the oil all gummed up, cleaning and adjusting was a royal pain in the ***. However they are my favourite .

The Kanon was a standard ratchet, slightly nicer than a Mitutoyo

The Mitutoyo was a recent purchase from Amazon, a disappointment. The ratchet knob was made of plastic.

 

[Lassen Forge]

I have both (Japanese) Mitutoyo and (American) Starrett, both work reasonably well... the Mitu's have held up better, the Starrets (especially the older ones) are fine, but need to be checked before I trust them. The Roch ones look pretty reliable as well, the Tesas are as good as any... I'm not that impressed with the newer offerings from Mitu, but mine are all older, well used, and well trusted.

You'll need a set of standards - trusted feeler gauges and a 1-2-3 block (or the metric equivalent - 25-50-75?) to verify and calibrate your calipers every so often.

The "speed" factor comes with practice - we had to do caliper readings for a few hours straight, as fast as we could answer what they threw at us for all of a few 2 hour classes. I also have a decent magnifying glass to double check, but that's a recent addition, as I didn't need it until recently...

 

[Samuel D]

Thanks for the comments, all.

I’m wondering how a constant-force mechanism is compatible with measuring different things. Say you’re measuring:

• the thickness of a sheet of steel
• the diameter of a steel wire
• a ball bearing.

The same force would cause greater elastic deformation of the item being measured as you go down that list. Wouldn’t you therefore need a very light feel to get a good reading of a ball bearing?

Is there anything stopping you measuring at a lower force than the ratchet clicks?

 

[kapster]

You don't have to use the ratchet thimble if you don't want to. The barrel is just like a standard mic, just has a small ratchet knob on the end.

The size error on the items you mentioned would be pretty insignificant if using the ratchet thimble or light pressure. I can't imagine you would need that kind of precision on those items. What is our usage for?

Someone mentioned standards above, if your getting just a 0-25mm you don't need one as you can set it to the anvil. 25-50 and 50-75, ECT would need them.

Sent from my moto g(6) using Tapatalk

 

[Samuel D]

You don't have to use the ratchet thimble if you don't want to. The barrel is just like a standard mic, just has a small ratchet knob on the end.

Great, that’s what I wanted to hear. No big downside to having the ratchet, then.

The size error on the items you mentioned would be pretty insignificant if using the ratchet thimble or light pressure. I can't imagine you would need that kind of precision on those items. What is our usage for?

One use I have in mind is to compare the dimensions of new and worn parts of machinery to see the effect of different lubrication regimes. However, I don’t know how much precision is needed for that, not having done this kind of thing before.

For example, new bicycle chains have a pin-to-pin distance of 0.5 inches (Shimano tried a metric 10 mm pitch chain a while ago, but thankfully the market wasn’t interested and the half-inch standard has remained). A chain is considered worn out when wear of the pins and bushings causes 1/16" of elongation over 12 inches of chain (24 links). I’d like to find out how much of that wear is at the rollers and how much at the bushings, and possibly compare those values for different manufacturers’ chains.

Differences in new chains also interest me. The half-inch pitch is standardised, but roller diameters are all over the place.

 

[Downwindtracker 2]

Bicycle chain is a standard numbered American chain, I think it's #37, but the joining links are different on bicycles. They have to get through the changers. There are at least two other 1/2" pitches. It's been decades since I rode or worked on bicycles. Roller chain on the other hand, I must have dealt with miles of the stuff.

A super simple check on chain, is put it on a flat and shake it back and forth, if it looks snakey, it's worn out. It's best to change it out before it wears the sprockets into a new pitch.

 

[anndel]

Mitutoyo (local machine shop), Starett (Ebay)or Brown & Sharpe (Ebay).

 

[californiaHank]

There are times I’d like to measure something with greater precision than my Mitutoyo 530-101 vernier calliper allows (graduation 0.05 mm, accuracy ±0.05 mm). For example, the thickness of a shim.

Mitutoyo lists hundreds of micrometer models in this PDF:

https://www.mitutoyo.eu/application/files/9415/5888/6605/Micrometers.pdf

Where do I start?

I don’t want to spend more than necessary on luxury, but I want something that works well and lasts – hence my interest in Mitutoyo whose entry-level vernier calliper has served me well for nine years and counting. But tell me if I should look elsewhere.

I see some models have different graduation (0.01 mm versus 0.001 mm) but the same accuracy (e.g. ±2 µm). Why?

Not sure I need a model with a constant-force device, but you tell me.

Do I need a standard too?

Thanks.

Mitutoyo is a good choice. I have 102 series mics and like them a lot. They're basic mics with 0.01mm resolution, though the markings and accuracy are such that you can easily see 0.005mm differences.

Most micrometers come with either a ratchet thimble or a friction thimble. Ratchet thimbles are more common than friction ones. Most Mitutoyo mics, especially in the smaller sizes, used to be available with a choice of thimble type, but it's hard to find a distributor that stocks the friction thimble variants anymore, because they're not big sellers. Ratchet thimbles are thought by some to be easier for a novice to use. Friction thimbles are said by some to give more consistent results on delicate/soft parts, but take a little more practice to become proficient in using the tool.

The 25mm version of the Mit 102 mic is P/N 102-301. It has a ratchet thimble.
The 25mm version of the same tool with a friction thimble is 102-221. I have one of those, but I'm not sure if it's still made.

You don't need a standard with a 0-25mm micrometer. There is an adjustment to zero the tool, but it takes a lot of use/abuse before you need to adjust the zero point, and if you buy a new set, or even a used set in good condition, you may never have to adjust them. (When you buy new micrometers, there's a suitable adjustment wrench in the box.)

Micrometers that measure parts larger than 25mm or one inch need a standard to set zero. Regardless of their size, mics typically have 25mm or one inch of travel. You need a standard that's 25mm or 1 inch smaller than their maximum opening, because that's where you set zero. So, you only need a standard for mics that open larger than 25mm. (When you buy larger mics new, they come with a suitable standard.)

 

[Karsa]

Even I love to use a mechanical micrometer, but my friend told me Mitutoyo is a good choice.

 

[Samuel D]

Mitutoyo is a good choice. I have 102 series mics and like them a lot.

Did you choose the 102 over the 103 for any particular reason? Prices seem to be in the same ballpark.

Most micrometers come with either a ratchet thimble or a friction thimble.

Despite reading reams of text on micrometers in the last couple of days, I’m still not clear on the difference. (Mitutoyo’s own explanations are entirely useless if you don’t have the two devices in your hand … in which case you wouldn’t need a written explanation.)

Have I got this right:

The little knob at the end = speeder. It does nothing that the larger barrel (the thimble) doesn’t do except spin more quickly between forefinger and thumb.

The thimble can be one of three types:

• plain: simple screw that translates your applied torque to axial force until something breaks
• friction: some sort of clutch that slips smoothly at a certain force
• ratchet: also slips, but with a hammering action as spring-loaded teeth slide over each other.

Questions then:

1. Can the slipping force of the friction or ratchet thimbles be adjusted?
2. Why would you choose a friction over a ratchet or vice-versa?
3. What’s the lock for?

Thanks for your lucid explanation of the other points, californiaHank. Appreciate it.

 

[davethorik]

In the pic I posted earlier, the smallest diameter of the thimble is the ratchet. I know they are replaceable, but I dont think adjustable. The larger knurled diameter would be your plain thimble.

You need to get a mic and practice with it. A lot of your questions will become self evident once you just practice. A set of gage blocks is good to check, although shims, bolts, ball bearings, dowel pins anything will work. I only say this because you mentioned a plain thimble being turning until something broke. Unless you have some Hulk level grip strength, you cannot break a micrometer by turning it hard (edit: by hand). But more importantly that is something you will never do, micrometer is about finesse.

And the lock is so you can get your measurement, pull the micrometer back from the work, and look at the size. Sometimes you have to put them in places the scale is not easily read.

 

[Samuel D]

In the pic I posted earlier, the smallest diameter of the thimble is the ratchet.

So Mitutoyo’s picture here is wrong then:

https://shop.mitutoyo.eu/pim/upload/mitutoyoData/image/bigweb/102-701_b2_eps.png

Doesn’t surprise me.

I only say this because you mentioned a plain thimble being turning until something broke. Unless you have some Hulk level grip strength, you cannot break a micrometer by turning it hard (edit: by hand). But more importantly that is something you will never do, micrometer is about finesse.

Sure. I was just trying to get clarification on what a plain thimble is in comparison to the friction and ratchet.

And the lock is so you can get your measurement, pull the micrometer back from the work, and look at the size. Sometimes you have to put them in places the scale is not easily read.

Got it.

 

[mowkep]

I have to laugh. I researched the mechanical digital Starrett mics I have for sale. $286 at Grainger and a couple other places. Then I look at the electronic digital mics and they are $150 and below. Scratch my head and then read the reviews......COO.....China

 

[kapster]

So Mitutoyo’s picture here is wrong then:

That setup looks like what's on my digital quantumike, the whole barrel is a ratchet included the small part. On their standard mic, or even their standard digital I believe, only the small knob at the end ratchets. The main barrel is non ratcheting.

Sent from my moto g(6) using Tapatalk

 

[Kevin54]

If you are only going to use the mic occasionally for measuring then pick yourself up a good used Starret 0-1 mic. I have one that is probably 50 years old and I've owned it myself fior 40 years. Just as accurate today as when I first acquired it. As long as someone didn't gorilla grip it and try to use it as a clamp you're good. For an 0-1, you really don't "need" a standard, but if you feel a need to, use a 1/2" gage block to check it. You already know that when it's closed it should read zero. So I always double check mine midways on the range. You can usually pick up a good used mic or two at a flea market, ebay, Facebook Marketplace, pawn shops, or from a retired toolmaker that is selling his equipment. It might cost you $20-$30 tops and will last you the rest of your life. BTW.....look for carbide tips.

Once you get a mic, you'll learn the feel of it. NEVER EVER tighten a mic down on anything. Use finesse on it. Once you sneak up on the part, then use slightly hold the thimble between your thumb and forefinger, lighten the tension until your finger and thumb slides around the thimble.

 

[californiaHank]

Did you choose the 102 over the 103 for any particular reason? Prices seem to be in the same ballpark.


Despite reading reams of text on micrometers in the last couple of days, I’m still not clear on the difference. (Mitutoyo’s own explanations are entirely useless if you don’t have the two devices in your hand … in which case you wouldn’t need a written explanation.)

I think the only difference between the two series is insulated vs plain steel frames. Most modern mics, including most digitals, seem to come with insulated frames. For me, I haven't noticed much practical difference. I've never used mine intensively or for long enough periods to where hand heat could affect measurement accuracy. The traditional plain frames are probably easier to keep clean in an environment with lots of flying metal chips and coolant, but I'm mainly measuring finished parts in a relatively clean space, so I chose insulated frames over plain.

 

[tymbo]

Mitutoyo vs. Harbor Freight
I found this video very interesting:

 

[mowkep]

For what it's worth you can buy any size gage block to use as a standard. I have .100 for setting tools on one machine and I can use whatever on the other machine. But aside from setting tool heights, they can also be used as standards.

 

[Downwindtracker 2]

Micrometers have been around for a very long time, they are one of the first tools an industrializing country makes. I have heard good things about the Chinese clones of the Swiss Etalon, even. Machinists put those Swiss ones at the top of their lists, but I've never used one.

 

[Git]

I would probably buy this one from Amazon Warehouse if it meets your requirements - used/package damage

https://www.amazon.com/gp/offer-listing/B00CHR9JWY/

 

[Samuel D]

After watching this video (especially this bit) I decided I didn’t need a vernier scale. So I went with Mitutoyo’s least expensive model, the 103-137. I might have gone with a Starrett for the all-metal construction if it had been more readily available here. Maybe I’ll get a Starrett 25–50 mm model in the future.

The Mitutoyo is a neat little thing. This is going to tell me a lot about the world.

Incidentally, the back of the box says Made in Japan. I thought production had moved to Brazil. Doesn’t matter to me either way.

 

[davethorik]

Mitutoyo vs. Harbor Freight
I found this video very interesting:

Are you replying to the right thread? Lol...op is in France, there are no HF there to my knowledge. And he didn't want digital mics. And he wanted Mitutoyo so you recommend cheap Chinese junk? Next time maybe read the post before responding.

So I went with Mitutoyo’s least expensive model, the 103-137. I might have gone with a Starrett for the all-metal construction if it had been more readily available here. Maybe I’ll get a Starrett 25–50 mm model in the future.

The Mitutoyo is a neat little thing. This is going to tell me a lot about the world.

Incidentally, the back of the box says Made in Japan. I thought production had moved to Brazil. Doesn’t matter to me either way.

Great choice. It will serve you well. I have seen some Brazilian mics, but they are older. They make some dial calipers and solid squares there, maybe more. The Brazilian stuff seems just as good as Japanese.

 

[Joebass]

Find a Mitutoyo combi-mic, its a mechanical micrometer with metric and English. Should be able to get one for under 100.00 on Ebay. For what its worth I own a fab and machine shop. I sold all my Starrett mics and went Mitutoyo. I like their mics and calipers best. My dial test indicators are Swiss, everything else is Starrett.

 

[davethorik]

Find a Mitutoyo combi-mic, its a mechanical micrometer with metric and English. Should be able to get one for under 100.00 on Ebay. For what its worth I own a fab and machine shop. I sold all my Starrett mics and went Mitutoyo. I like their mics and calipers best. My dial test indicators are Swiss, everything else is Starrett.

Yet someone else who didnt read the thread. Lol

 

[tymbo]

Are you replying to the right thread? Lol...op is in France, there are no HF there to my knowledge. And he didn't want digital mics. And he wanted Mitutoyo so you recommend cheap Chinese junk? Next time maybe read the post before responding.

Yes, I replied to the right thread, and yes I read the post.
OP asked a very open ended question about micrometers.
He never stated that Mitutoyo was his only option.
He never stated he didn't want digital.
I never recommended Harbor Freight- did you read my post?
I said "I found this video interesting."
You sure made a lot of assumptions from my comment.

The point of the video(I'll bet you didn't watch it) was that there was NO difference in accuracy or precision, but a BIG difference in price.