Why are good metric micrometers so hard to find?

[Ischgl99]

I feel you! Yes, they have a metric set 0-150 mm, but it is only with 0.01 mm graduation. Isn't that odd?

No, very few applications need 0.001mm resolution in that range, and you will need a temperature controlled room to make use of that. I worked for FAG Bearings as well as a German machinery manufacturer as a field engineer, we never used 0.001mm mics above 50mm in the field. What are you measuring that you need that precision at 200mm?

Mahr is a German micrometer manufacturer, they don’t have anything other than 0.01mm in the metric series, so it looks like Starrett might be your only choice if you really need 0.001mm resolution in the larger micrometers.

I bought my metric Mitutoyos piecemeal on Ebay and have a set up to 150mm now. None of them are 0.001mm resolution, I have a 0-1” in 0.0001” resolution if I need that in the smaller sizes. You can find them at really good prices in many cases since most people don’t want metric in the States.

 

[Oscar Lazo]

I have a metric micrometer set from Dasqua. That is reasonable priced and the quality is good enough for hobby use (it is by far not a Mitutoyo). It has a 0.01 mm resolution but you can easily estimate the values in between at 0.005 mm.
I am not capable of machining within 0.001 mm. At the best, most of the time, I get 0.01 mm.
Even if you can measure at a resolution of 0.001 mm it doesn't mean it is accurate at 0.001 mm. For that accuracy you need to keep the room temperature constant and have the micrometers calibrated at a regular base.

Yeah, 0.01 mm graduation is not hard to find, and it is affordable. But as I see things, you should ideally be able to measure with greater accurracy than you can machine, because otherwise, you'd loose certainty on those good 0.01 mm accurate parts you're making, wouldn't you?

And I find it surprising that it is so hard to find affordable 0.001 mm or even 0.002 mm graduated micrometers when 0.0001'' are commonplace, and these are very close numbers.

Yeah, I understand the difference between accuracy and resolution, and the role of thermal expansion. But the imperial mics I'm looking at with 0.0001'' usually hace an accurracy between 0.00005'' and 0.0002'' which is acceptable. I have an AC in my workshop, but if that is not enough temperature control, I am willing to call it willful over-engineering.

 

[Oscar Lazo]

No, very few applications need 0.001mm resolution in that range, and you will need a temperature controlled room to make use of that. I worked for FAG Bearings as well as a German machinery manufacturer as a field engineer, we never used 0.001mm mics above 50mm in the field. What are you measuring that you need that precision at 200mm?

Mahr is a German micrometer manufacturer, they don’t have anything other than 0.01mm in the metric series, so it looks like Starrett might be your only choice if you really need 0.001mm resolution in the larger micrometers.

I bought my metric Mitutoyos piecemeal on Ebay and have a set up to 150mm now. None of them are 0.001mm resolution, I have a 0-1” in 0.0001” resolution if I need that in the smaller sizes. You can find them at really good prices in many cases since most people don’t want metric in the States.

Perhaps I am confused at something. I don't suppose I really need 0.001mm at 150 mm range, but I find it odd that tenthousandths (0.0001'') are fairly commonplace and affordable (check these at $258 for a 0-6'' set), and 0.0001'' = 0.00254 mm which is not far from 0.002 mm. Why does something comparable in metric require Starrett, and a budget blowout?

 

[Winegrower]

I don't agree with your basic premise. Look at Aliexpress. There are pages and pages of metric micrometer sets, 0.001mm for extremely reasonable prices.

I have tested a number of calipers, micrometers, gage blocks, gage pins, 123 blocks, digital calipers, of a pretty wide range of brands and prices...literally every one I tested met their basic spec, generally plus or minus the lowest resolution.

 

[Just for fun]

Perhaps I am confused at something. I don't suppose I really need 0.001mm at 150 mm range, but I find it odd that tenthousandths (0.0001'') are fairly commonplace and affordable (check these at $258 for a 0-6'' set), and 0.0001'' = 0.00254 mm which is not far from 0.002 mm. Why does something comparable in metric require Starrett, and a budget blowout?

I'm not sure what kind of quality or accuracy you will get buying that inexpensive set of micrometers. In my option to get the accuracy you want you are going to have to spend a little more money and buy something high quality.

 

[Oscar Lazo]

I don't agree with your basic premise. Look at Aliexpress. There are pages and pages of metric micrometer sets, 0.001mm for extremely reasonable prices.

I have tested a number of calipers, micrometers, gage blocks, gage pins, 123 blocks, digital calipers, of a pretty wide range of brands and prices...literally every one I tested met their basic spec, generally plus or minus the lowest resolution.

Yeah, I suppose they would be cheap there, but their stuff tends to be junk. I dunno..

I'm not sure what kind of quality or accuracy you will get buying that inexpensive set of micrometers. In my option to get the accuracy you want you are going to have to spend a little more money and buy something high quality.

Right. That sounds reasonable. But I am getting mixed messages here, somehow. I guess if Winegrower says vendors tend to be true to their specs, I might give the cheapos a go, but of course, buyers beware... Maybe that could summarize the whole thread...

 

[Larry$]

Is the difference between a decent quality .01 and .001 micrometer the way the barrel is marked rather than the accuracy of the thread? To get to the .001 the ones I've seen, mark the barrel radially for that last .001 to .009!
I personally have a decent eye that can estimate between the .01 marks in ±.003 increments. If the rest of your kit is capable of .001 then being able to measure to that is worth spending the $ for the high quality measuring tools. Unless you have an unlimited $ supply there may be better places to spend it. Will your surface grinder hold .001 over it's length? It's your $, spend it wisely.

 

[Advil]

Maybe just start collecting various sizes of cheap digitals then they'll do both. Make sure they look like reasonable build quality and that they say they have carbide tips.

Today a 1-2" electronic showed up at my door from Amazon because I needed one to measure metric threads on my lathe spindle for an adapter. At $28.50 I sure wasn't expecting much but I checked the 1" standard it came with against my Mitutoyo calipers and it came out bang on 1.0000" so the standard is within a few tenths or better. So I then zeroed the micrometer to the 1" standard and tested the ratchet and it repeated to 1.00000 over and over. I was pretty shocked. Decided to start treating it like a real tool.

 

[SouthernChap]

Yeah, 0.01 mm graduation is not hard to find, and it is affordable. But as I see things, you should ideally be able to measure with greater accurracy than you can machine, because otherwise, you'd loose certainty on those good 0.01 mm accurate parts you're making, wouldn't you?

And I find it surprising that it is so hard to find affordable 0.001 mm or even 0.002 mm graduated micrometers when 0.0001'' are commonplace, and these are very close numbers.

Yeah, I understand the difference between accuracy and resolution, and the role of thermal expansion. But the imperial mics I'm looking at with 0.0001'' usually hace an accurracy between 0.00005'' and 0.0002'' which is acceptable. I have an AC in my workshop, but if that is not enough temperature control, I am willing to call it willful over-engineering.

0.001 mm is just under half a tenth (0.000039701").

0.01 mm is just under half a thou (0.0003937008")

I would think for the majority of small to medium sized shops doing 'paid for' work, measuring at half a thou (given that their tolerances for most parts are likely to be be in the low single digit thou; a couple of thou for example) would be perfectly acceptable.

For most hobbyists, being able to measure at a level of half a thou is entirely sufficient.

Take a look in Machinerys Handbook at the standard fit charts. The tolerances for most of the fits are shown in thou.

I'd think the use case for 0.001 mm metrology would be calibration of metrology tools in in-house toolrooms not in a hobbyist work shop.

I think you may have fallen into a trap that gets all of us in the hobbyist world (it's a trap that you see in other hobbies too; recreational shooters looking for half MOA at 500 yards for example). We get excited about a level of precision that rarely, if at all, isn't relevant to us.

If you get a genuine Mitutoyo micrometer that has a resolution of 0.01 mm and don't chuck it around the shop, you'll get a quality of measurement that will definitely be sufficient. Here's the relevant specs for an economy Mitutoyo analog mic:

Mitutoyo 103-137 (0.01mm) Ratchet Stop Economy Design Micrometer 0-25mm

• Resolution: 0.01mm
• Accuracy: ± 0.002mm

That will give you a measurement that will be accurate plus or minus about 0.00015".

Now sadly, just like on any forum, there'll be "willy-wavers" who insist that their hobby work demands micron level accuracy. Also there'll be some others who are/were production machinists/engineers and genuinely forget that this is a hobby forum and have their 'precision production' head on when posting.

Either way, for hobby shop work, a metrology resolution at 0.01 mm should by and large be entirely sufficient.

 

[Ischgl99]

Perhaps I am confused at something. I don't suppose I really need 0.001mm at 150 mm range, but I find it odd that tenthousandths (0.0001'') are fairly commonplace and affordable (check these at $258 for a 0-6'' set), and 0.0001'' = 0.00254 mm which is not far from 0.002 mm. Why does something comparable in metric require Starrett, and a budget blowout?

I have never seen, nor heard of a metric micrometer with 0.002mm graduations, so I doubt that exists. I’m not sure how many people would be interested in graduations like that compared to either 0.01 or 0.001.

Is the difference between a decent quality .01 and .001 micrometer the way the barrel is marked rather than the accuracy of the thread?

The accuracy of the Mitutoyo 0.01 and 0.001 micrometers is the same, so I’m not sure the screw threads are any more accurate. I think it’s probably mostly in the cost to run a different production series with lower demand as well as the increased quality control testing required for the more precise units.