26 tpi threads

[roadrocket]

1/4'' BSF and 1/4'' BSCY are both 26 tpi. What's the difference?

[Billybream]

Its the thread angle, hard to distinguish with the naked eye, but thread gauges would identify.

[roadrocket]

Thanks! Maybe a stupid question, but would a nut from any of the two fit the other bolt?

[rocker21]

yes, the difference is so small, for all practical purpose's they will fit,  there are other 1/4 x26 tpi threads that would be difficult to use like BSB (british standard brass) but they are not very common now. the thread angle and the form is different and it would be a tight fit.

[chaterlea25]

Hi RR
Enough info here to keep you busy for a while 

http://www.gewinde-normen.de/en/index.html

John

[BSA_54A10]

The trouble is that in place of the threads contacting on their entire face they make a point contact.
Which ever is the harder will deform the weaker and from then on you have what feels like a worn out thread.
It is similar to trying to fit a garden gate galvanised nut onto an electroplated bolt ( and we have all done it at least once ).
Because it is only 1/4 " diameter heavy handed Hank can force the nut to run, once.