They look more like calibration weights  than gauge blocks. The varying size of the central section could be their metric.

I would sort them into sets with the same size centres as a starting point, and see how many sets you end up with.

PS random thought – could they be a set of Go/NoGo samples for testing penny arcade slot machines? An old penny is just over 30mm diameter and comparing them with the 28mm circle on the cutting mat they look about that size.

They look as if they could be sections of bar that have been heat treated in some way – possibly case hardened.  Polished and etched on one side and then stored as quality control specimens.

They could also be some form of calibration target for X-ray Diffraction or some other high tech analysis ( high tech back in the 1950s !)

Rod

Bucket cam shims?

bucket cam shims. as Bernard said.

On 11 July 2026 at 12:46 martin haysom Said:

bucket cam shims. as Bernard said.

Every day is a school day 🙂

Did not know They had “kick the bucket” shims!

Also Alfa Romeo engines

1. On 11 July 2026 at 16:31 Michael Gilligan Said:

   … as used with the Hillman Imp engine, of fond memory

   MichaelG.

   I think your memory must be failing, SWMBO had an Imp when I met her, I spent at least as long mending it as driving it. Nice car when it was running, but sucking cooling air from underneath wasn’t a bright idea, so we had endless overheating problems. As for setting thd tappets, taking the dngine out made it easier, fortunately you didn’t need a crane, and it didn’t need doing often. When we eventually sold it I poured a can of STP in to quieten the tappets