I bought some Whitworth thread size guages at Ally Pally yesterday and am
puzzled by part of the markings. They all have a number followed by G. The
number is clearly the number of teeth per inch but what does the G
represent? A few of them also have other numbers after the G, such as 48G
3/32 (three thirtyseconds) and 7G 1 1/8 1 1/4 (one and one eighth & one and
one quarter). What are these other numbers?
- posted 17 years ago