Starret 1uM reading??

[Munty Scruntfundle]

So, as I was getting unreasoningly pissed off with my digital micrometres burning batteries like tomorrow didn't matter, I thought I'd get a couple of mechanical versions. In this study case, the 436.1 0-25mm.

It's a lovely bit of kit, very repeatable and feel lovely to use, just one problem though, the manual (as usual) is pants!

I'm fine getting the major reading, but when it comes to getting the last .001(s), am I looking for the line on the barrel closest to a major (.05) division as in the diagram, or is it the closest line of all of them? Like calibrating an old ink jet printer?

I'm pretty sure it's meant to be the line that matches up regardless of the actual number on the thumb wheel, but the manual doesn't state this, I reckon the picture is a bit missleading.

Many thanks.

 

[Inspector]

Is your manual the same as the first few pages in their catalog?
https://www.starrett.com/vdoc/Catalog 33 - Section 1 - Micrometers
There are quite a few Youtube videos if you search for How to read a metric/Imperial micrometer.
Here is one.

Pete

 

[Gerry]

You can't read 0.001 (1 micron) on a vernier micrometer it is only scaled to read 0.01 (10 microns)

Gerry

 

[Dalboy]

In the instruction linked to by Inspector on page 23 does your mircometer have the horizontal lines as in fig B and C if so you can read down to 0.001

 

[Munty Scruntfundle]

You can't read 0.001 (1 micron) on a vernier micrometer it is only scaled to read 0.01 (10 microns)

Gerry

Nope!

 

[Munty Scruntfundle]

Is your manual the same as the first few pages in their catalog?
https://www.starrett.com/vdoc/Catalog 33 - Section 1 - Micrometers
There are quite a few Youtube videos if you search for How to read a metric/Imperial micrometer.
Here is one.

Pete

Many thanks, page 23 explains things much better than the 2 page mini leaflet sent out with the box.
I did search around on youtube, finding good examples of metric micrometer readings is difficult and the ones I did find all show getting the last .001 with major divisions, just an unfortunate coincidence I suppose.

So, it's the single matching line, not necessarily the major division.

 

[J-G]

As Dalboy has questioned, is your micrometer a 'Vernier' micrometer or not? Gerry has incorrectly mentioned 'Vernier' in his statement that it cannot read to 0.001mm.

The essential thing is that the Mic has a 'Vernier' scale on the Sleeve. The Mitutoyo in the video posted by Pete is not a Vernier Mic. - that has whole mm markings above the datum and ½mm markings below. A Vernier Mic. has whole & ½ markings below the datum and a 'Vernier' scale above.

Reading a Vernier Mic. is no different from reading a regular Vernier Caliper - one uses an accurate screw to move the jaws (Spindle to Anvil) and the other just slides the jaws under friction. The 'Vernier' part is simply the scale which has 9 divisions in the space that would normally take 10 by means of which you can interpolate more accurately a further order of magnitude. This is just by noting which marks line up most closely.

Here is a vernier scale :

I've marked the two lines that line-up in red.

A Vernier Mic. just has the scale rotated 90° - the principle is exactly the same.

If you become very proficient, it is even possible to read to the next order of magnitude by judging which two lines are closest to absolute matching should there not be an absolute line up!

EDIT - I've just done a quick 'Google' and can't find a Starrett 436.1 0-25mm with a Vernier scale. All their descriptions for that model show readings down to 0.01mm. The 25-50 model does show 0.001 though so that must have a 'Vernier'.

This doesn't mean that one doesn't exist - just that I can't find one

 

[deema]

I had a look too, I can’t find that model either just a 0 to 1” version with 0.01 resolution. I’d be interested in seeing a photo of it.

 

[Dalboy]

EDIT - I've just done a quick 'Google' and can't find a Starrett 436.1 0-25mm with a Vernier scale. All their descriptions for that model show readings down to 0.01mm. The 25-50 model does show 0.001 though so that must have a 'Vernier'.

This doesn't mean that one doesn't exist - just that I can't find one

If you look on page 34 onwards in Inspectors link you will find the 436 models

 

[J-G]

I hadn't looked at Inspectors Link - now I have, there is just one 436.1 model that shows a capability of measuring to 0.001mm - the MXRL.

As you can see my 'Google' comment was an Edit - I only added it because I couldn't find one. My post was really just to try to make it clearer to Munty that the 'Vernier' issue - and how to read it - had little to do with it being a Micrometer, just understanding how a Vernier Scale works is the important fact.

 

[Devmeister]

As I recall, the 436 is one of the most popular micrometers made by Starrett. Mine are imperial. The std model reads to 0.001 or one thousandth. There was an option to get a tenth trading version. The last digit or tenths is not read off the standard barrel but off a set of vernier lines separate from the barrel.

Now, after a bit of practice, you can see how the barrel lines line up. If it’s dead nuts on, you have no tenths. But you can guess the tenths by roughly judging how far off the barrel lines mis match. Pretty easy to see 5/10th. Harder if your chasing tenths.

Also keep in mind that when your chasing tenths, lots can go wrong not to mention the calibration of the mic in the first place. Accuracy is often equal to money! It can get really expensive when your chasing tenths.

I have a Pratt Whitney Super Mike! It’s a bench model that weighs about 80 pounds and I use it to chase tenths. It has a huge dial and designed for this.

In the absence of tenths, I am happy to get to one thousandth. In woodworking I use an analog starrett dial caliper. I have a digital one but it had no off button so you buy lots of expensive batteries. I love the dial caliper. Nice easy to read dials and I get darn close to one thousandth.

if I do threading I go to the micrometer. If I do press fits I go to a tenth reading micrometer. Anything super critical I use the super mike. Things like machining high speed spindles for shapers etc.

 

[porker]

I think there is some confusion on this thread between imperial and metric. As @Devmeister states it’s 1 thou not 1 micron

 

[pe2dave]

A few years ago I hung a 6x magnifying glass right in front of me on the wall behind the workbench.
Used for my vernier... Also for mm rulers! Accuracy back to where it was when my eyesight was ... better than now.

 

[J-G]

I think there is some confusion on this thread between imperial and metric. As @Devmeister states it’s 1 thou not 1 micron

I don't think there is much confusion - it seems to me that the OP is using a Metric Mic. and looking for readings down to 1 micron (0.001mm). Anyone working in Imperial measure and looking for readings down to 0.001" is looking for 1 thou. Those on the other side of the pond tend to despise Metric and talk about 'Mils' rather than 'Thous' - what they talk about when discussing 0.001mm I've no idea

I work in both but with a strong preference for Metric but as an apprentice in the 50s had to measure Imperial slip gauges to complete the final inspection chart with the number of millionths of an inch they were away from 'nominal' (0.000001").

 

[deema]

There is definitely a 1 micron micrometer in the range as has been highlighted already. I couldn’t find it on the Starrett web site, but thats probably me being useless!

I also like manual stuff rather the digital stuff, so I’m with the Munty. I also recently bought a new to me 1 micron 25mm micrometer by Mitutoyo, it has a mechanical readout which I love. Unfortunately others seem to love them too…..so they are hard to find at a reasonable price. For those who haven’t seen one before you can see the horizontal 0.001 divisions on the fixed barrel. The mechanical readout reads down to 0.01mm which is brilliant for 99% of most stuff

 

[Craig22]

Mitutoyo do a caliper that is has a resolution of 0.1um and a maximum permissible error of +/-0.5um. It will set you back £1,884