Starrett micrometer identity

[ianjParticipant @ians]

Hi . Can any one identify the use for this Starrett micrometer. It has a pointed spindle and a single"V" anvil.

Regards Ian

[ianjParticipant @ians]

Starrett micrometer identity

[NJHParticipant @njh]

Hi Ian

Screw thread micrometer I think you will find.

Cheers

Norman

[MICHAEL WILLIAMSParticipant @michaelwilliams41215]

Yes – screwthread micrometer and it will be specific to one thread system eg Whitworth or ISO.

The slopes of point and anvil engage the thread flanks .

MW

[ianjParticipant @ians]

Thanks for that.

I assume its Whitworth as its stamped No. 436-1"

Ian

[Richard ParsonsParticipant @richardparsons61721]

You cannot make the assumption that it is for Whitworth thread forms. There are a set of 60° threads which are also inch standard. These are the ‘Unified’ threads (UNC/NC, UNF/NF/SAE). These are American.

Rdgs

Dick

[Nicholas FarrParticipant @nicholasfarr14254]

Hi Ian J, your micrometer may be a user modified one, as the 436 series have a flat anvil and spindle. Please see scan below.

Screw thread comparator micrometers are 210 series, and have a conical anvil and spindle. Please see scan below.

Regards Nick.

[Ian S CParticipant @iansc]

Thought it might be used to measure the likes of the wall thickness of tube or similar. Ian S C

[ianjParticipant @ians]

Hi.

Dick. Good point. I've measured the pointed spindle angle and it's 55 degrees.

Nick. I also looked on the Starrett web site & their thread mics have a double "V" on the anvil. The one I have looks to be original not modified.

Ian. Yes I can see how it could be for that.

Regards Ian

[Ian S CParticipant @iansc]

I would have saidas you that the anvil should haveat least a, as you say double"V", the mic must be at right angles, which would mean that the points should not meet, but be half the thread pitch apart sideways, well thats my idea anyway. Ian S C

[ianjParticipant @ians]

Now that I look at the anvil "V" more closely, it's actually flat topped so would not bottom in a thread.

I can see how it would measure tube wall thickness.

Maybe it is a user modified one.

Ian

[MICHAEL WILLIAMSParticipant @michaelwilliams41215]

A flute or spline micrometer measures across the anvil tips like a normal micrometer .

A thread micrometer measures the distance between the bedding down locations of the tapered anvils in the tapered thread flanks . The anvil points do not touch at all . As supplied there would have been a setting piece and a data table .

Measure something and see if answer makes sense for either of above .

MikeW

[NJHParticipant @njh]

Hi again Ian

A little web search returns this for Starrett screw pitch micrometer. Starrett is an American company hence it uses "real" units of measurement ( inches!) and the 1" refers to the capacity 0 – 1 in. I suspect that the 436 is the range, which appears to be a girder frame type. The one in the link looks like a deluxe version (maybe, using the same reasoning, from  the 575 range?.) There are a few notes in the "product description" which may be of use.

So that's another little task you've set us – aint the web wonderful – so many questions – so many answers!

Regards

Norman

 

Edited By NJH on 26/02/2012 13:06:11

Edited By NJH on 26/02/2012 13:08:26

Edited By NJH on 26/02/2012 13:09:00

[ianjParticipant @ians]

Hi Norman.

Thanks for that information.

The description states:-

"This Micrometer has a pointed spindle and a double V-anvil, both shaped to contact the screw thread. The micrometer reading therefore gives the pitch diameter."

The anvil on mine has a single flat topped "V" which lines up with the point on the spindle.

As MikeW states above that would not measure a thread.

I think I'm going a long the line of thinking it's for measuring tube wall thickness or it's a user modified one, although the spindle & anvil do look to be factory produced.

Regards Ian

[NJHParticipant @njh]

Well Ian the search continues!

Starrett shows this for measuring tube!

I'm sure you will find a use for it anyway!

Regards

Norman

[Nicholas FarrParticipant @nicholasfarr14254]

Hi, although Starret is an American company, you will find they have factories in many parts of the world, one of which is in Jedburgh Scotland, which is where most Starret tools you find in this country were made, you can find them at http://www.starrett.co.uk and if you go to the downloads tab and scroll down to precision tools catalogue, you will find a MUL-T-ANVIL mic series 220 which will do tube wall thickness. The 436 series was and still is a standard micrometer, as shown in the scan I put in my previous post.

Regards Nick.

[methusalaParticipant @methusala]

Hi All, I have a micrometer that I modified for measuring undercuts on turned

components . I m/cnd a 1/16 flat on the anvil, and ground the spindle end to 1/16 dia. x 3/16

long. maybe the above mic was modified for this reason!

hope this helps ,Colin.

[ianjParticipant @ians]

Hi All.

Just emailed Starrett with the photo & description of my micrometer. Will post you with there reply, if any. ( I find some companies are better than others over such questions)

Ian

[ianjParticipant @ians]

Well straight from the horses mouth (Starrett) the mystery is solved.

It's a crimp micrometer.

We can all sleep easy to night now.

Regards Ian

[NJHParticipant @njh]

Well Ian so there you are – we are all wrong!

Still a very useful item to have in your tool box – just get out at every opportunity and measure a few crimps!

Cheers

Norman

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