Finds for today anyone have information on this spring compressor?/QUOTE]
That spring compressor was a catalogue item in the late '30's and '40's.
It was advertised as a tool for inspecting valve springs for tension at a specified compressed length, which was set by a stop on the device.
It was used with a torque wrench, and meant as a less expensive substitute for the valve spring checkers of other makes, which had an inbuilt dial scale.
The practical use of this device related to a common practice of the time, a 'minimum cost' 'valve job', in which the valves were removed, the usual badly burned one(s) replaced with new, and the others 're-faced' on a 'valve grinder'.
The valve seats would be inspected for cracks, and if a crack was found, the head or block would be repaired by 'pinning' if the crack was minimal enough, and a 'seat ring' fitted. (sometimes, a crack would extend so far that the head, or block, in the case of side-valve engines, was not readily repairable, requiring the replacement of that head or block, much to the dismay of the vehicle's owner.....this was all too common with the Ford 'flathead' V8 engines)
The valve seats would be ground with a 'hard seat grinder' and 'narrowed' to suit the valves.
The valve spring inspection, using that device, was one aspect of this job, as any 'weak' valve spring would be replaced with new, if found. A weak or cracked/broken valve spring would cause a valve to burn fairly quickly, as the valve would not be adequately held to its seat.
(all this may well be 'more than you wanted to know', to be sure......but its the 'context' of that device......... a little glimpse into the daily work of the 'wrench pullers' of half-a-century ago.
cheers
Carla