Lubricating a high helix worm in a Mercer indicator

Lubricating a high helix worm in a Mercer indicator

This topic has 4 replies, 4 voices, and was last updated 1 November 2026 at 15:02 by roy entwistle.

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1 November 2026 at 09:20 #872250
Mark Davison 1
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@markdavison1
I have a slightly sticky Mercer ‘back plunge’ indicator. The plunger has a hard steel spigot the operates a high helix worm that in turn operates the needle via a gear. I’ve dismantled it. Cleaned and reassembled and it is now worse than before. There’s nothing obviously wrong with any of the components. The plunger runs smoothly in its bore. There did appear to be a tiny amount of a dry lubricant on the worm. That’s gone after I cleaned it. I assume that’s why it is now stickier that before. The question is,

What lubricant should I apply the the worm/spigot? I’m assuming some sort of dry graphite/molybdenum grease very sparingly?

It looks wet as I flooded it with IPA before resorting to disassembly.
Advert

1 November 2026 at 10:11 #872251
noel shelley
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@noelshelley55608
What do watch makers use ? Noel
1 November 2026 at 10:22 #872254
JohnF
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@johnf59703
Well I think I recall reading that no lubricant should be used ? BUT for me I think all mechanical things need a lubricant and when i have had to “fix” a dial indicator I have used clock oil — very sparingly and up to now no problems.

Clock oil is I believe formulated so that it does not “gum up” or dry out

John
1 November 2026 at 10:53 #872257
Mark Davison 1
Participant
@markdavison1
<p style=”text-align: left;”>I’ve got Starrett indicator oil for the bearings. What ever I wiped off wasn’t oil. It was some form of dry film ‘grease’. There was no sign the thing has ever been apart before so I assume it is there by design.</p>
<p style=”text-align: left;”>
I was wondering about this sort of thing</p>
<p style=”text-align: left;”>
https://wrekd.com/products/woodland-scenics-hl652-dry-white-lube</p>
<p style=”text-align: left;”>Or</p>
<p style=”text-align: left;”>https://wrekd.com/products/woodland-scenics-hl651-dry-graphite-w-molybdenum</p>
<p style=”text-align: left;”></p>
1 November 2026 at 15:02 #872304
roy entwistle
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@royentwistle24699
The other pivots look to be dry, I would lubricate those with watch oil (not clock oil)

and then try

Roy
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