Open a smiths rev counter

[gs.davies]

How do I open an 80mm smiths rev counter where the bezel is rolled over all the way round?

[Peter Laidler]

As told to me by an old school Instrument Technician. The roll-over part is thin brass. Slip a thin screwdriver blade underneath the rolled over part and slowly work your way around....., maybe a couple of times, slowly lifting the roll seal. By squeezing the case you'll find that the bezel will unclip.

Norton motorcycle instruments were like that.......

To re-fix. Might I suggest that you take the advice of my old Instrument Teccie pal too. Mark 3 equidistant points on the now slightly raised rolled edge and mark 3, say, 3/8" segments. Cut away the remainder. Cut away 3 matching segments on the case and you'll be left with a standard undo-able case and bezel. Ready for next time.....

Don't forget to replace the 5mm Bezel-to-glass sealing ring and the 2mm bezel to surface ring too

[gs.davies]

Thanks Peter, I’ll give it a go.

Think I got a bargain with this one, 8k, square digits. It even seems to work after a fashion on electronic ignition

[Allen Brzeczek]

With great difficulty i'm afraid.

Some years ago I tuned a frogeye, the mechanical rev counter maxed @ 6000 so I created a hybrid using the Smiths internals in the original AH casing so as to match the speedo. I literally had to prise the lip on the bezel open sufficiently to enable separation from the body. On reassembly I imagine that in the factory they had a machine to roll the lip of the bezel over but the only option i has was to peen it down with a drift and hammer - not that satisfactory but with a bit of patience I managed to get a reasonable result, nothing to be proud of but didn't look too bad fitted back in the dashboard.