mystery object

Pre-payment coin meters would need a way for the price per unit to be changed and that would be my guess as to the purpose of the gears. The dial was presumably connected, probably through gearing, to thread A and it would indicate which gear was engaged, showing either pence per unit or units per coin inserted.

Colin Bignell

bits of a parking meter?

We were somewhere around Barstow, on the edge of the desert, when the drugs began to take hold. I remember bof saying something like:

The famous Lost Bits of Babbage's Engine.

In message , Grimly Curmudgeon writes

What's the difference?

The numbers are designed to show upright through a window, positioned at about "2 o'clock" from the spindle. "7 1/2" is pretty close to upright. There are 15 numbers and 15 gears in the cone so the numbers probably do show which gear is selected.

There might be some form of latch that prevents A turning unless it is released.

What are the top and bottom views of the mechanism?

We were somewhere around Barstow, on the edge of the desert, when the drugs began to take hold. I remember james saying something like:

Ask the cool operator.

In message , bof writes

Its for hand rolling cigarettes

In message , bof writes

Its a long lost Antikythera

Cross-post to uk.eggheads?

:-)

And the mystery might be helped if we knew what needed to be measured in units of 8.

Which bit inserts the roach?

Yes found another plate in the box of bits, which aligns nicely with the numbered cog to give this:

which confirms nightjar's 'price per unit'

Yes there is, but even unlatched it's jammed

Here's the top view where you can see the cam and latch:

the bottom view is just a flat plate.

So I think mystery solved, thanks to all.

bof set the following eddies spiralling through the space-time continuum:

The integers and halves on the dial suggest it's for checking the sizes of shoes.

In message , Prai Jei writes

I guess there must be a second device for sizes 8 1/2 up