Any way to determine date for old Grover "PAT PEND" tuners?

[chucke99]

I have five chrome Grover tuners marked "PAT. PEND. U.S.A." on them. Digging around and checking eBay, it looks like they could date anywhere from 1959 to the late 1960s. I highly doubt they are very early ones, but is there a way, via subtle differences, maybe, to narrow down just when they were made? I have no idea what they were taken off. I got them in a box of loose, old parts.

Any help is greatly appreciated.

 

[Mark Kane]

Check, Dr. Vintage site. I'm not sure but he may have info on that

 

[chucke99]

Check, Dr. Vintage site. I'm not sure but he may have info on that

Thanks!

 

[simonm]

I have been through this exact conundrum. IIRC they were first used on Martins in 1959. Chrome I think. The Pat Pend text is quite shallow and and close to the outside ring, like the ones on Dr Vintage, and deeper and closer to the centre like yours is later. Dr V doesn't offer any dates, but 1968 crops up somewhere, but I can't remember where - is that the year they first appeared on Gibsons as stock? I giess it took a long time to get the patent passed.