Thread: Ultimate guide to Micrometers

Had this emailed to me and thought that some of the Members on here might be interested.
https://www.practicalmachinist.com/i...o-micrometers/

Kryn

Had a bit of a look - a bit disappointing, with not much info or detail supplied I would hardly call it "ultimate".
It looks more like an advertising page than anything else.
I would have expected some justification and hard nosed testing results and justifications before just saying "buy this one'
The page linked to on calibration is similarly brief.
Same applies to the PM's section on Dial indicators

I will have to see if there is a model for my use 17mm inside diameter, and i will need to find some info on how those inside measuring one's work

Originally Posted by gazza2009au

I will have to see if there is a model for my use 17mm inside diameter, and i will need to find some info on how those inside measuring one's work

If you already have an outside mic and a digital calliper its cheaper and more versatile to get yourself some of these
Screen Shot 2019-04-19 at 12.37.07 pm.png
https://www.ausee.com.au/shop/item.aspx?itemid=3502

In my opinion for what little it is worth, I think, its just the way the yanks use words.

Ultimate is just one of those words used by them, particularly on the net, that annoy me just a bit.

Oh my god, wow, ultimate is used again and again until the meaning is negated down to being a click bait word.

Dictionary type quote

" 2.
being the best or most extreme example of its kind.
"the ultimate accolade"
synonyms: best, ideal, greatest, supreme, paramount, superlative, highest, unsurpassed, unrivalled, topmost, utmost, optimum, quintessential; rareapogean
"the ultimate gift for cat lovers"
antonyms: worst "

Look how many times you see that word on the net. Struth, on U toob It is damn near a guide for the writers' nationality re the title to the "what ever" is posted.

The ultimate welding bench, the ultimate belt grinder and what have you.

So when I see ultimate, especially in the U toob context, I prepare for good or mediocre, at best, or perhaps ignore the vid.

In this case, it could be handy, especially if you are new to imperial micrometers and need a quick study to understand the use and operation of the tool.

I used a similar link for students to get a grasp of metric micrometers.

Thank you for posting, Krynn, anyway, it may help someone .

Grahame
Resident Picker of nits

Originally Posted by BobL

If you already have an outside mic and a digital calliper its cheaper and more versatile to get yourself some of these
Screen Shot 2019-04-19 at 12.37.07 pm.png
https://www.ausee.com.au/shop/item.aspx?itemid=3502

I have seen these before on ebay How accurate would they be with those tips they look big and only slightly rounded would it interfere with the inside radius?

Gazza2009

On my set the individual pockets in the wallet are marked A, B.C,D,E,F.
Under each letter there is a working range.

Eg: A is 8 to 12.7mm-the smallest I can measure.

F is 90 to 150mm - the largest of the range.

The tools will ( hopefully) each have a letter marking on their shanks .
The radiu on the ends are clearance ground to suit the chosen hole diameter.

To confirm press in the spring loaded ends and measure them.
That would be the smallest you can measure with the tool.
I assume the lettering and ranges are a standard,i have not compared them with others.


Grahame

Originally Posted by gazza2009au

I have seen these before on ebay How accurate would they be with those tips they look big and only slightly rounded would it interfere with the inside radius?

The cheaper ones on eBay May suit your current needs but if you can you may be better off buying a used brand name set, some of the cheaper ones I have been told can become a bit sticky.

Before you attempt to use them if you purchase them you will have to learn/know how to use them, the same as learning how to use a micrometer correctly.

Originally Posted by gazza2009au

I have seen these before on ebay How accurate would they be with those tips they look big and only slightly rounded would it interfere with the inside radius?

They are as accurate as your mic.
Even on the small sizes the contact radii are fine - holding them up to the light inside their minimum rated orifice clearly shows a point like contact of the contact pins with the ID.
I have two sets - a cheap set which works just as well as the more expensive one.

May pick up a cheap set off ebay or i might just use my digital calipers i can get away with the jobs being within 00.40mm out so far i am down to around 00.15-00.20mm

I understand how to use the micrometer just when i take a measurement i may need to turn the timble to the closes mm than back as the 0-45-0 i may be half a mm off

Originally Posted by gazza2009au

I will have to see if there is a model for my use 17mm inside diameter, and i will need to find some info on how those inside measuring one's work

Hi Gazza,

Don't fret about it Do the same as I do and get a pair these

Spring Calliper.jpg

I have all four of this type, but the one you would be interested in is the last one.

Originally Posted by BaronJ

Hi Gazza,

Don't fret about it Do the same as I do and get a pair these

Spring Calliper.jpg

I have all four of this type, but the one you would be interested in is the last one.

Hare and Forbes has those for under $15 that is cheap it jut doesn't say what the minimum measuring width is

Hi Gazza,

The ones that I use, I have two pairs, one goes from about 10 mm to 80 mm or so, and the other from 40 mm to well over 150 mm. You use your micrometer to measure over the ends just like the other type.

The outside ones get almost no use at all, simply because the digital calliper is more convenient.

I'll go pick one up when shops reopen

One problem with callipers is they don't reach very far into bores so its not possible to check deep bore sizes.
Using the the ID jaws of basic callipers restricts blind bore measurements to a depth of about 15 mm.

FWIW The 1/2mm wide flats typically found on digital calliper ID jaws leads to an underestimation of a 10 mm ID bore by about 0.02mm, (and less for larger bores).