Old Hole Plate Questions

Into my possession came this.

180, 144,84, 50 holes. & Appears old (see font used in stamping)

It's approx 1/4inch thick - 7inch diameter - bronze.

Any thoughts on the specifics of what this is or what/how it was used.

Could it be specific to clockmaking??

Thanks in advance.

Regards.

Frank C.

Probably used for direct indexing for gear cutting and similar. The disc looks like clockmaking rather than industrial. I don't know if the nuimbers are common tooth counts for clocks.

Andrew

The three outer rings of holes appear indexed into 12 segments.

The 50 holes ring is indexed into 5 segments.

Regards.

Frank C.

The factors of the hole circles correlate with some time-related things.

180 = 2x2x3x3x5 so it contains 60 (seconds in a minute, minutes in an hour)

144 = 2x2x2x2x3x3 so it contains 24 (hours in a day)

84 = 2x2x3x7 so it contains 7 (days in a week)

What puzzles me is that there is no obvious time-related thing that relates to 50 (2x5x5).

The sub-divisions they have stamped on the circles probably has some significance. For instance, why is the 84 stamped every 7 when it could equally be stamped every 6?

Seven is a prime number so can't be factorised?

Andrew

10 and occasionally 20 is used for (clock) pinions. Just look for 'wheel cutting engine' and you will see something familiar. Often they only needed a few rows of holes so were not trying to get lots of rows of primes like a dividing head plate, but used a large plate for accessibilty and mechanical advantage.