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moore and wright internal micrometer

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sparky mike17/07/2019 21:14:27
187 forum posts
49 photos

I recently bought a traditional style 50's 60's Moore and Wright internal micrometer set. I would like to know if the rods adjust individually and how.

No paperwork/instructions came with the set.

Mike.

roy entwistle17/07/2019 21:31:35
1033 forum posts

Not on mine they don't

Roy

David George 117/07/2019 21:31:44
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908 forum posts
301 photos

Hi Mike which internal mic do you have, a model No and picture would help.

David

Andrew Johnston17/07/2019 21:58:52
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4849 forum posts
543 photos

On my Moore & Wright 2" to 12" internal micrometer I'm pretty sure the additional rods are adjustable:

internal_micrometer_me.jpg

The shortest rod (bottom left) doesn't appear to be adjustable. In that case I assume the micrometer head is adjusted. I think all the other rods are adjustable. Looking at the shortest of the other rods (top left) there are spanner flats on the left hand end and the knurled nut at the right is a separate item, and can therefore be loosened. I don't know what the exact method of adjustment would be, but no doubt it would be clear once the knurled nut is loose.

Andrew

Edited By Andrew Johnston on 17/07/2019 22:00:54

DMB17/07/2019 23:30:14
922 forum posts

Google for M&W manual - its in 5 languages incl English by owners of M&W

Edited By DMB on 17/07/2019 23:30:49

mechman4818/07/2019 13:25:11
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2449 forum posts
376 photos

IIRC all the rods are a fixed length; the measurement is taken via the thimble, e.g. a 6" rod is fitted into the thimble & locked in place with the thumb screw, you get the extra 1" of measurement via the thimble as normal hence 6" - 7" internal diameter range.. Any adjustment to accuracy is done on the thimble as in a outside micrometer 'zeroing' . I believe the spanner flats are to aid in seating the rod hard up to the thimble face & in removal of same as the rods can often get tight in the thimble as they tend to be a tight fit. That's my excuse .. devil but open to be corrected.

George.

Andrew Johnston18/07/2019 14:24:52
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4849 forum posts
543 photos

Further investigation shows that the end with the spanner flats is screwed in, and is a very tight fit:

extension_rod_me.jpg

On "calibration" against an external micrometer and gauge blocks the internal micrometer reads about 1 thou under with the end screwed fully home, So it can be adjusted to be exact.

internal_calibration_me.jpg

However, I do nor believe that to be the correct means of calibration. The knurled ring is definitely screwed onto the plain shaft that fits into the micrometer thimble. I expect that shaft to also be screwed into the extension rod, so the knurled ring can be used to set calibration. However, the knurled ring is very tight, and I don't feel like fudging an extension piece just to prove a point.

As new M&W are claiming an accuracy of 0.0001", I find it difficult to believe that they are machining extension rods to that accuracy as a matter of course in production. Much easier, and cheaper, to machine to a looser tolerance and calibrate.

Andrew

sparky mike18/07/2019 22:04:58
187 forum posts
49 photos

I have to measure between a couple of shafts in order to duplicate the housing that they rotate in, but wondered how accurate these extra shafts are.As my largest micrometer is 3" max, not sure how I could check the larger rods for size.I have a height vernier and surface plate, but would not like to guarantee result that way.

I tried to find the manual on Google, but nothing came up. My internal micrometer is same as in photos in latter posts.

Mike.

Anthony Knights19/07/2019 00:19:16
270 forum posts
87 photos

An old engineer I knew used to say "If you can't make it accurate, make it adjustable"

Michael Gilligan19/07/2019 07:00:09
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13975 forum posts
605 photos
Posted by sparky mike on 18/07/2019 22:04:58:

... wondered how accurate these extra shafts are.As my largest micrometer is 3" max, not sure how I could check the larger rods for size.I have a height vernier and surface plate, but would not like to guarantee result that way.

.

You probably need some of these, Mike [many sizes on the drop-down list] : **LINK**

http://www.starrett.com/metrology/product-detail/1-Precision-Measuring-Tools/11-Precision-Hand-Tools/1101-Micrometers/110107-Micrometer-Standards/234A-2

Then rig your height gauge as a comparator

... easier if you have a minimum of three hands angel

MichaelG.

Nicholas Farr19/07/2019 07:00:34
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1975 forum posts
936 photos

Hi, the rods are adjustable with a spanner on the anvil end as Andrew Johnston has said and according to the data sheet below, is the correct method.

internal mic001.jpg

These Mics are made in sets and the rods should be kept complete with the body they were originally made for, furthermore when fitting the rods, the "0" digits on the rod and the body should align up with each other.

001 - copy (1024x802).jpg

Regards Nick.

Edited By Nicholas Farr on 19/07/2019 07:01:25

sparky mike21/07/2019 07:43:54
187 forum posts
49 photos

Thanks Nick for the blueprint. I will print that off and keep it in the box. I bet a lot of you guys have never seen the instructions!! Re. setting gauges, my best bet would be to get myself a few larger micrometers, up to 6" at least.

I have slip gauges so with both that would be handy.

Why does it take the best part of your life to gather all the tools that you needed many years ago ?

Mike.

Nicholas Farr21/07/2019 09:10:23
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1975 forum posts
936 photos
Posted by sparky mike on 21/07/2019 07:43:54:

Why does it take the best part of your life to gather all the tools that you needed many years ago ?

Mike.

Hi Mike, usually cash flow in my case. pleased the information has helped you.

Regards Nick.

Michael Gilligan21/07/2019 11:09:44
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13975 forum posts
605 photos
Posted by sparky mike on 21/07/2019 07:43:54:

... my best bet would be to get myself a few larger micrometers, up to 6" at least.

.

I have sent you a personal message, Mike

MichaelG.

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