Later, step-framed, WT movements.

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Later C40B & C40C WT movements took on a stepped mainframe design. The movement was compact and provided a clear area for the crown wheel and bevel gears. One might say they were "industrialized" in comparison with the earlier, "organic" main frame designs. 

The factory drawing alongside clearly states that this is a C40B. I don't yet have a drawing of a C40C to share here.

 And the physical reality: A C40B stepped frame WT. Expansion couplings are provided for at least three dials. Left, right and forwards. Another may face backwards out of sight.

There has been some reinforcement and simplification over the earlier curved frame models. Plated components are the norm to avoid corrosion.

The gathering pallet is now doubled to provide a straight draw on the ratchet [escape] wheel. 

The contact steady bars are of the later, pressed variety.

A near identical, step framed, C40B courtesy of Simon Boyd.

The typical drive to the lead-off work is clearly visible on the left. A crossbar is driven by a slotted channel to provide a positive, non-slip drive to the distant clock hands. While simultaneously allowing for thermal expansion and building movement.

 Another step-frame C40B in clean condition.

Pressed steel contact steady bars. All plated components.

This fine example was described as a C40C by the vendor. I called it a C40B and the mainframe shows B1 in the central casting. I must admit that I cannot identify any obvious differences from the C40B above.

The movement had been domesticated. By being installed into a fine, furniture quality, display cabinet.

The clock dial is unusual. Most WTs, with a forward facing bevel wheel, would have a time setting dial with mention of name and patents. Perhaps the domestication required a readable time indication? If so, it was tastefully done.

An almost perfectly matching step-framed WT from Clock.doc. C40B? Or 40C?

 WT R 1.jpg (JPEG Image, 640 × 609 pixels)

Perhaps it is merely a matter of scale? The C40B at the top of the page has a perforated crown wheel. Both of these  C40Cs have a solid crown wheel to the bevel wheel cluster. The black paint is usually considered as a sign of an early movement.Yet both "C" movement have later plated components and pressed, contact steady bars.

Click on any image for an enlargement.

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