Mystery DTI

[OuBallieParticipant @ouballie]

Tidying up my drawers, in preparation for experimenting with foam and papier-mache in organising items in them, I came across this 1.1/2" Mercer G.91 DTI.

The only part that moves is the black bezel, the indicating lever and arm being fixed.

The contact 'pin' is fixed as well, and unscrews.

Any help as to how and where it is used appreciated please.

More photos uploaded into new DTI folder.

Ah, I can insert photos when using the MacBook.

Geoff – Hoping to clear up this mystery.

[OuBallieParticipant @ouballie]

Mercer

[Steamer1915Participant @steamer1915]

Hi, Admittedly I haven't a definite answer for you, but I wondered if the contact point would unscrew from the back of the gauge and then screw into the end of the long arm?

Steve.

[John McNamaraParticipant @johnmcnamara74883]

Hi Ouballie

You may find a small drop of light oil applied to base of the knurled probe on the back will release it. I suspect it is stuck fully pressed in.

Cheers
John

[Steamer1915Participant @steamer1915]

Just found this on Fleabay:- **LINK**

So just to answer my own question _"no"

"The dial moves from the back"

I think John has it right.

 

Edited By Steamer1915 on 11/06/2013 16:23:55

Edited By Steamer1915 on 11/06/2013 16:24:29

[WindyParticipant @windy30762]

I have a Verdict DTI very similar to your Mercer and used it years ago when setting the cam timing on my Triumph bike engines.

Paul

[Michael GilliganParticipant @michaelgilligan61133]

Geoff,

Sorry to say, I'm sure John is correct … that looks very stuck.

By all means try John's suggestion of some light oil; but you will probably get a nasty surprise if you open it up …

I have one of the larger DTIs in pieces at the moment; this was only sticking very slightly, but there is furry white alloy-corrosion inside. [they don't like condensation]

MichaelG.

[MICHAEL WILLIAMSParticipant @michaelwilliams41215]

Hi OuBaillie ,

Your pic shows a standard back button dial gauge . Mercer gauges are still available as new items . Here is a website page showing modern day version :

**LINK**

MikeW

[OuBallieParticipant @ouballie]

John & MichaelG,

You both got it in one.

After reading the responses, I loosened the probe enough to get a thumb nail under it, levered and it moved ever so slightly, so as mentioned, it's stuck.

So a little 3in1 as suggested.

Mystery solved.

I did 'manage' to remove the bezel, but quickly got that back.

MichaelG – What exactly do you mean by 'nasty surprise'?

I hesitate/am reluctant to take it apart, as I have visions of all sorts of bits and pieces heading for the nearest black hole, that seem to inhabit all workshops, of whatever size or tidiness.

I wonder if a sonic bath will free the insides.

Will post update.

Windy – Details of how it's used for timing would be appreciated please.

Cheers all.

Geoff – Just about recovered from weekend

[Ed DuffnerParticipant @edduffner79357]

Hi Geoff,

I inherited a Mercer G.92. I find it very useful when tramming my milling machine with the dial always facing upward.

Ed.

[Michael GilliganParticipant @michaelgilligan61133]

Posted by OuBallie on 11/06/2013 18:20:08:

 

MichaelG – What exactly do you mean by 'nasty surprise'?

I hesitate/am reluctant to take it apart, as I have visions of all sorts of bits and pieces heading for the nearest black hole, that seem to inhabit all workshops, of whatever size or tidiness.

.

Nasty surprise = furry corrosion

I will post a photo sometime.

MichaelG.

.

P.S.   This is what it should look like

Edited By Michael Gilligan on 11/06/2013 18:56:24

[OuBallieParticipant @ouballie]

Update.

Since my first post, I have been applying normal as well as 3in1 oil to the plunger, and it has finally today freed enough to be sliding smoothly.

The gauge now appears to be working as designed, but I will continue applying the lighter of the two oils for a while yet, moving the at the same time.

Ta for all the help.

Geoff – If only the same treatment would work for me

[Peter TuckerParticipant @petertucker86088]

Hi Geoff,

Be carefull of the three in one, If left on moving parts for some time it can set like varnish.

Peter.

[Sub MandrelParticipant @submandrel]

3 in 1 contains castor oil IIRC.

Neil

[mechman48Participant @mechman48]

Have you tried WD40 or similar release fluid?

George

[Bill PudneyParticipant @billpudney37759]

DON'T USE WD40!!!!!

Sorry for shouting.

WD40 turns into a waxy gooey mess if left for any time. Use it for displacing water (thats what the "WD" is for…Water Displacing), and then wipe up any residue

Up here in 'Straya there is a thin oil called "Inox", available as aerosol or a can. There must be something similar in the UK. Inox is the near perfect stuff for things like this. I suppose the perfect stuff is clock or watch oil.

cheers

Bill

[Geoff TheasbyParticipant @geofftheasby]

A distant memory says not to use oil on dial gauges, only graphite dust.

Regards

Geoff

[OuBallieParticipant @ouballie]

Thanks for the warnings!

Graphite dust I have as well as sewing machine oil.

Geoff – Today is workshop day at last

[Michael GilliganParticipant @michaelgilligan61133]

Posted by Michael Gilligan on 11/06/2013 18:52:10:

Posted by OuBallie on 11/06/2013 18:20:08:

MichaelG – What exactly do you mean by 'nasty surprise'?

Nasty surprise = furry corrosion

I will post a photo sometime.

MichaelG.

.

Geoff,

Sorry for the delay … I finally got around to re-sizing some pictures; only to find that I had already done that [side-effects of Anno Domini]

My furry DTI is not the back-plunger style; but it is a Mercer, and the corrosion is fairly typical of one that has suffered condensation.

MichaelG.

Three more pics in the Album.

[OuBallieParticipant @ouballie]

Thanks for the photos MichaelG.

I'm still reluctant about taking mine apart, namely because I'm not sure how to, and seeing that it appears to be working fine, I'd rather let sleeping dogs alone.

Geoff – Nosh and coffee coming up

[vic neweyParticipant @vicnewey60017]

I had one of these in a small lot of engineering bits & pieces, mine is stuck the same as Geoff's was.

By removing the little screw on the back I've dripped in a little watchmakers oil but I'm not sure exactly how you would use it ? My other dials have either a piston or a little pressure lever but what should this one have to operate it ?

[Howard LewisParticipant @howardlewis46836]

I inherited two smaller versions when clearing a workshop.

have never used them, but am sure that one day, one or the other will come in handy.

At least such clocks avoid the contortions sometimes required to read a plunger clock. Tramming a mill is one such time.

Most of the time the clock of choice is a Verdict finger clock

.(Probably because I am just too idle to dig out and set up any other! )

Howard

[vic neweyParticipant @vicnewey60017]

But what is put in contact with the workpiece? I have a couple of finger types and several more plunger types but this one shows no way to use it as far as I can see

[Michael GilliganParticipant @michaelgilligan61133]

Posted by vic newey on 02/07/2021 15:24:15:

But what is put in contact with the workpiece? I have a couple of finger types and several more plunger types but this one shows no way to use it as far as I can see

.

The link that I posted previously is dead … but here’s what it should look like externally: **LINK**

http://www.europacprecision.com/files/products/126/1/f40.pdf

Note the short plunger shaft labelled M2,5 – 6H

That is, I believe, what is/was stuck on Geoff’s specimen.

If it moves … usage should be self-evident

MichaelG.

.

Edit: __ This should help

Edited By Michael Gilligan on 02/07/2021 15:56:51

[SandgrounderParticipant @sandgrounder]

I use mine quite a lot on my Sieg milling machine, mount in either the drill or collet chuck and it's so easy to run the table along and square up a vice or angle plate etc.

John

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