Thread NNomenclature - Why Is It Called '510'?

[Eddie.Willers]

Folks
Title says it all...does anyone know why we give the numbers 510, 901 801 etc to different thread types? Are they size related? Thread pitch? The info is needed for the Wiki.

Any ideas?

 

[Switched]

Dunno

510 = 7 x 0.5 mm
901 = 8 x 0.75 mm
801 = 9 x 0.75 mm

 

[BardicDruid]

The numbers are the Manufacturers model number, when Hon Lik started all this he didn't use the numbers you see today, they evolved.
RN4072 became DSE801
RN4075 became DSE901
RN4081 became DSE103
The Joye 510, KR808 and M401 were original ideas.

Edit: Corrected, memory isn't what it once was.

 

[scalewiz]

Confused yet? If you don't know what you're buying, I can sell you anything!