A sticky Mercer Gauge

Can anyone suggest a way of possibly relieving the stickiness of a small Mercer gauge as shown in the photo. The gauge shows every sign of being otherwise in very good condition and in the past I have had the back off and (possibly inadvisably) tried putting a small drop of a light machine oil on the moving spindle but all to no avail. Any suugestions to help solve the problem would be much appreciated

Cleaning off the old oil before adding more is probably the key. I sparingly use lighter fluid, but I don't know what an actual horologist would use.

Wrong move. First move is a few drops of petrol on the plunger to dissolve old oil there. As recommended by an old Mitutoyo service sheet (pre-WHS days!). They recommend no oil on the plunger and make no mention of putting any inside. If anything it would be some kind of non-gumming clock oil I should imagine .

Long Island Indicator Service have a good website with useful info about dealing with dial indictors. LINK

I've picked up several sticky ones over the years, and thus far, all have freed up with lighter fuel to wash out the gunge.
A tiny drop of thin non-drying oil to the rack inside, and then cleaning off even that from the plunger, do it doesn't attract dust in my mixed workshop.
I've use horologists oil, but also Balistol Universal Oil, which works well for all sorts of jobs.
https://ballistol.co.uk

Bill

I have a similar one with the same problem. Had it apart several times and it always goes sticky again. Now I just give it a squirt of brake cleaner each time I need to use it.

Take the back off and have a look inside

Some models are prone to corrosion, and that may inform your decision about what to do with it.

MichaelG.

See this, from 2015 : **LINK**

https://www.model-engineer.co.uk/forums/postings.asp?th=108056

MichaelG.

Never had much luck with Mercer dial guages at my last employment - they all seemed to fail that way, so I would suggest not wasting your time and bin it.

Webought the guages new & independantly certified by a local specialist test company, as they were used for final acceptance of alignments on rebuilt CNC machines. The guages were treated carefully and stored in the original packaging between uses but, almost inevtiably, the next time they were brought out the plunger would be rough & sticking.

We gave up on Mercer guages eventually after this had happened several times & went to Mitutoyo guages. Never had to replace one of those.

From (rather distant now) memory, I think it was the plunger racks that were the problem - very, very fine teeth.

Nigel B.

It would appear that the Mercer was not a particularly good buy then? (Must admit that it came from a ME exhibition some time in the pre Covid past)

This is how I did it for over 5 years, not Mercer but Batty, Maintained probably a dozen of these for 5 years.

Squirt lighter fuel down the plunger hole and push plunger in and let it come out under spring pressure.

Repeat if necessary.

Never oiled them ever.

Watching, forgot to tick box.

Hi all - I have now had the back off the gauge and gave the spindle a clean using IPA and a cotton bud. Overall impressions are is that all looks to be in remarkably good order and quite clean. First thoughts are that it might a weak spring problem as in mid travel the gauge is very responsive but then fails to return to the end of its travel. Replacing the spring would appear to be a simple job but where would it be possible to obtain a suitable replacement? Thanks for all the help and suggestions being provided.

That’s clearly in ‘orders of magnitude’ better condition than mine was

Personally, I would prefer to find the underlying fault, not disguise it by fitting a stronger spring: But if that’s what you decide to do, then shortening the existing spring by one coil would probably do the trick.

MichaelG.

Blondihacks 14 minute tutorial

I had never thought of using IPA for cleaning things other than my tonsils.

If you go to the 'Madmodder' site, :-MadModder - Index there are various tutorials for servicing many different types of dial indicators. 'Search' works well.

Regards Ian

IPA = Indian Pale Ale......

Now I am confused!!!!

India Pale Ale

Robert Butler

Or Isopropyl alcohol AKA propan-2-ol

Hi All -Progress (or lack of) dismantling the Mercer gauge. I have removed the top plate and cleaned all the moving parts including the rack and pinion with very little evidence of crud and so now suspect binding of the spindle in the gauge body. Next problem is how to remove the spindle from the body which involves removing the hairspring pinion wheel in order to clear it from the rack but I cannot see how to do this. Second problem is how to remove the side spring retaining arm from the spindle in order to be able to withdraw spindle from the body. Blondihacks had to resort to a massive pair of pliers to withdraw the pin. Is the pin a screw fit or a press fit? Any hints and tips would be most welcomed.