Pulley Threads bad, looking for Tap, bolt 09440024
 

Dear all, on the GM catalog it is a 7/16 - 20x2.25 300M POR

0.437" diameter
20 threats
is 2.25 the slope.

What tap do I need UNC or UNF

Most taps to buy are listed 7/16 20.
How do I pick the correct one?

BOLT, (7/16-20X2 1/4)

BR Mo

7/16" - 20 is UNF(fine), 7/16"-14 is UNC(course)

Tap you need is 7/16 -20 UNF.

7/16" is bolt diameter(=.437"), 20 is threads per inch, UNF is Unified National Fine.

UNC is Unified National Course.

2.25 is the length of the bolt in inches, not the slope. You've been playing with metrics too much, haven't you :D

Hello Eric if I go after the ANSI table I have 20 threads per inch.

1 inch is 25.4mm. If I devide 25.4mm/ 20thread I get the slope 1.27mm per thread. Am I correct.
That 2.25 in is the lenght.
Than should be this the correct thread.

Thanks for your help.

7/16" - 20 UNF 0,438 11,112 9,90 20 1,270

You are correct, 1.27mm per thread