Moore & Wright 903

I recently bought a M&W 903 inside micrometer at a market / boot sale.

I think there are at least three parts missing: The handle, a collar that holds the measuring rods in/on the micrometer part and a screw that goes in the side of the micrometer barrel. They are shown on model 903s for sale.

Can anyone show me how to assemble the micrometer for use? The instructions are not clear. Does anyone know how I should make the missing collar(?)

Hi Peter welcome to the forum. The collar is a hardened and ground piece which is a spacer to adjust the anvil by the range that you have bought. There are four different models made 1-2 2-8 2-12 8-33 and still available as well as the spares. The anvil is held in by the screw from the side and loosened to remove, then you slide the spacer collar over the anvil shank, making sure that it is clean and then tighten side screw. The handle is a split ring with attached tube that has a long screw which clamps round the end of the micromiter just to hold it down a long hole. Have a look at the Bowers Group web site as they are the makers of the Moor and Wright range now. The collar could be made from a piece of silver steel which is easily hardened and then lapped to length depending of your accuracy needed or buy a replacement. The screw is easily turned depending what the thread is and you have a die and knurling tool to suit screw.

David

Hi Peter, as George says the collar is hardened and ground and it is called a "distance piece" and should be exactly 1/2" long, all the rods are full inch's long and the barrel moves 1/2" therefore you use the distance piece to make up the different lengths when needed, i.e. the smallest measurement is 2" to 2-1/2" put in the distance piece and you get 2-1/2" to 3" etc. The scan below should help.

Regards Nick.

Edited By Nicholas Farr on 19/12/2020 16:26:49

Oops! Sorry, I forgot I'd asked the question here.

Thanks for the replies.

I am still uncertain what holds the extension bars onto the end of the micrometer if you don't use the half inch collar.

I'll dig it out again & see.

Thanks

Hi Peter, the little knurled screw shown on the top left hand side of the micrometer body in the scan above, holds the extension rods in with or without the distance piece (collar) you can't use the distance piece without one of the rods.

Regards Nick.

Hi All,

This is what I have got. I don't see how to connect the rods with the micrometer part.

I know one rod is missing and I have two the same.

Peter,

It looks like the first thing you need is this: **LINK**

https://www.model-engineer.co.uk/forums/postings.asp?th=103028&p=1

MichaelG.

I was at the Luton Stockwood Park car show on Sunday, the exact M&W 903 was up for sale, could of been the same one. I had a quick look at it but thought I would only use it a few times, so left it alone. Hope you get it sorted Peter.

Bob

If you look at my latest album, there is a picture of my M & W 903.

The previously posted picture of the instruction sheet (blue ) should make it's operation pretty clear.

Suggest that you print it off and keep it with your 903.

Slackening the small knurled knob on the micrometer barrel allows the anvil to be withdrawn, so that another can be put into it's place, before retightening the knurled knob.

The small knurled sleeve is 1/2 inch long, and can be slipped over the stem of an anvil to extend the range of measurement by 1/2 inch (The micrometer barrel only covers 1/2 inch, so it is needed )

The Handle screws into the tapping opposite the small knurled knob.

The smallest internal dimension that it can be used to measure is 2 inches.

Since I very rarely find a need to measure bore above 2 inch diameter, mine doesn't see a lot of use!.

Howard.

Edited By Howard Lewis on 29/06/2021 11:56:14

Making a replacement for the missing handle should present little difficulty.

The Handle is an 8 inch long piece of 1/4 diameter bar, knurled, with what appears to be a 5 BA thread x 1/8 inch long at the end.

Making extension anvils will be more difficult. They have a spherical end, and need to be hardened, as well very accurately made, spherical to the end of the collar that butts against the micrometer body.

Howard

I think I see the problem looking at your setup.

1) I don't have a knurled screw on my micrometer body just the hole for the handle. Also my micrometer body is not plated.

2) The removable Anvil for 2 inch measurements screws into the main body so when I unsrew it the hole is too large for the extension bars and is threaded internally.

When I bought it the chap had two for sale and I believe some of the parts may have gotten mixed up which is why I have two of one length bar.

I also don't think I'll get much use from it but when you need it - you need it.

Thank you for your help - easy when you know how!

Edited By Peter Molyneux on 29/06/2021 15:40:46

Hi Peter, I don't think you have the correct mic for those rods, it should like like the one in Howard Lewis's album that he referred too. The instruction sheet refers to the 902 set, which only has the six rods, the 903 has 12 rods, but the mic is the same for both of them.

Regards Nick.

It would be nice if you could return and find the other set, and maybe make two two useable sets from an unholy mixture.

Howard

Hi Howard,

Already tried. No luck. The other owner is probably as frustrated as I am.

Oh well, necessity is the mother of invention...

Majex45

Thank you everyone for your help. It looks like I need to buy a different micrometer body or make an adapter.