Unidentified micrometer head

[old mart]

This is on ebay UK, any ideas what it is used for?

https://www.ebay.co.uk/itm/Boxford-L...wAAOSwkedeFwi6

[J Tiers]

Looks like a 0.0001" resolution (directly) head. Starrett made them also.

Used in a specialty jig or for alignment/measuring such as a microscope stage, or similar, or for plain measurement.

[Hopefuldave]

It looks like the micrometer found on one end of a jig borer gauge tray for fine adjustments - the user puts gauge blocks in the tray for measurement of axis movements (e.g. start at the last bore or a reference point with gauges clamped between micrometer head and hard stop on table, start spindle, take out 1.3703" of gauge blocks and advance to the hard stop - voila, a 1.3703" movement to the next bore) - there would be gauge trays and micrometers on both X and Y axes, the micrometers are for getting set accurately to the reference point on the work (e.g. the 0.0 corner on a jig plate).

Dave H. (the other one)

[old mart]

Looking at the base with the vee and flat which may be hard chrome plated, it might be placed on the ways of a machine and just held in place while in use.

[Peter.]

I've got two of those. They came off a platform for a measuring microscope. Direct-reading to 0.0001"

[loose nut]

It says that it might be off of a Boxford lathe, there must be some indication of that, so there is a good chance it is a micrometer saddle stop for that Boxford.

[old mart]

It sits on the bed, or vees the wrong way round for it to be part of a lathe. Peter has it, I would very much like to see a picture of the setup.

[frankie]

The only place I have seen a micrometer head of that size is on optical comparators.
frankie

[Peter.]

It sits on the bed, or vees the wrong way round for it to be part of a lathe. Peter has it, I would very much like to see a picture of the setup.

Long gone I'm afraid. It was incomplete so I robbed the good parts off it and got rid of the rest.

[BCRider]

The only reference to "Boxford" is the title. And that's a bit of stretch because it doesn't look like anything I'd see on a regular lathe.

There is the part on the one picture that had most of the words "MICROMETERS Ltd" and "...IELD, ENGLAND" on the barrel. A search for "micrometers ltd Sheffield England turned up an online to read book about micrometer makers. And lo I found that the only maker with the word "MICROMETERS" directly in their name is Shardlow Micrometers located in Sheffield England found in the Contents and on P145. So I'm thinking that the barrel unit itself might be by them.

As mentioned most of the big micrometer makers also sell the "raw movement" that can be incorporated into special needs. So the assembly as shown might well be off a Boxford machine. But I'm rather thinking that the micrometer movement itself is from a specialty supplier.

Howzzat for online sleuthing

PS; Ya knowz… it's almost scary that something this esoteric can be found in only a couple of minutes worth of checking. And in a way just as scary that a book of that sort is found on the web. Someone took the time to scan something that specialized and is paying the cost to host it on some server. Like Kudos to them for sure! But it still blows my mind. And perhaps to some extent the thoughts of the author AND publisher that made the decision to put together a list of that sort and publish such a book. Or is there a healthy underground society of micrometer collectors and speculators that NEEDS a book of this sort? Is there a Kelly Blue Book equivalent for micrometers?

[754]

The only place I have seen a micrometer head of that size is on optical comparators.
frankie

Automotive boring bar setters use big micrometer head like that.. pricey tool.

[Paul Alciatore]

One bid; around $30. Sounds like a bargain.

[old mart]

That one bid is just the starting price the seller has put in to at least get something back if somebody makes a bid of 10p more. The head would come out of the body and be useful to somebody, it is probably too big to turn into an actual lathe saddle stop. I hope it finds a good home.
Some Boxford lathes were a similar colour.