Moore & Wright depth gauge - information, please!

I have just acquired an M&W depth gauge from a forum advertiser:

The base is marked "2675 IN" and the there is a "56" under "Moore" on the sleeve:

The gauge seems to be complete and in good condition for its age but, unsurprisingly, came without instructions (I have, of course, looked online but without finding anything specific to this model). At first glance, I can't see how the rods are retained and should be grateful for guidance.

The top knurled knob is removed and the relevant rod, depending upon depth measured, is inserted and the knob replaced. Check calibration using a slip gauge.

Alan.

The line drawing on P46 of this old catalogue shows it quite well
https://archive.org/details/moore-and-wright-catalogue-no-61-1961/page/46/mode/2up

Bill

Thank you both.

This type of gauge is new to me and I see now that, confusing the end cap with a ratchet, I had made the elementary mistake of inserting the rod from the base end!

I think I am still going to have to dismantle, clean and lubricate as the ring nut under the cap is loose and this seems to be disconnecting the sleeve from the thimble so that turning the latter does not alter the reading.

Any further pointers would be welcome.

Incidentally, I note from the helpful line drawing that M&W redesigned the base which is noticeably more curvy than mine; I speculate that this may have been intended to make the gauge easier to handle in use.

PS A further point arises from the note on the drawing: what I thought was the type number may be a dimension, hence the "IN"; confusingly, in my 1970 catalogue, number 56 is a jenny caliper.

Edited By ega on 02/03/2023 12:54:21

When fitting a depth rod to the micometer head always ensure that the mating faces are very clean,any minute spec of grime will affect the calibration.

Hi ega, this scan may be of use to you. I don't know what the 56 is, but my one is the same model as yours and has 54 on it, and is in almost the same type of box, as the central channel where your head sits, extends fully to the right hand side in my box.

Click on the scan for a bigger view.

Regards Nick.

Edited By Nicholas Farr on 02/03/2023 16:29:29

2.675" I fancy is the height of the instrument to add to depth rod to give the lenght of a rod. To calibrate will require a set of slip gauges. only the 0 - 1" can be set as is. To set, Calibrate, using the 2 little spanners with the instrument and adjust the collars on the rod. Noel.

Nigel, Nick and Noel:

Many thanks for the further information.

The decimal point in 2.675 is indeed just visible in my photo.

M&W also made a type 53.

Also note that when you insert the depth rod required give it a little twist as it meets the mounting surface. If you look closely at the mounting surface it has two grooves which will act to clean the mating faces.

Colin

I had the toolmakers make a special rod for my Mitutoyo 0-6 depth gauge, somewhere in between the 2" and 3" rods. This was used to measure the stroke of a hydraulic cylinder used on Airbus main landing gear and landing gear door uplocks. Otherwise I would have to changed rods each time the stroke was measured even though the stroke was less than 1". I still have it, not much use now.

 The 2.675" will be the length of the 0-1" rod from the tip to the underside of the top flange. Add 1" to that for each successive rod. Not easy to adjust, fortunately rarely required.

Edited By old mart on 02/03/2023 20:54:51

Edited By old mart on 02/03/2023 20:56:25

old mart:

From today's Guardian crossword: "Europe's largest manufacturer of commercial aircraft (6)"

Colin:

Did you mean the slots in the ring nut? I took these to be for tightening but I suppose they could also do what you say.