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36tpi screw in 32tpi nutplate - did Vans really intend this?

U

unladenswallow

Member
I'm working through chapter 37iS/U (cowling) of the KAI. I've just spotted that on page 16 they call for twelve AN525-8R8 screws which have 36 threads per inch to be screwed into K1000-08 and K1000-08D nutplates which have 32 threads per inch. Did Vans really intend this? Should they have specified AN525-832R8 screws (32 tpi) instead as they do on page 18?
 
unladenswallow said:
I'm working through chapter 37iS/U (cowling) of the KAI. I've just spotted that on page 16 they call for twelve AN525-8R8 screws which have 36 threads per inch to be screwed into K1000-08 and K1000-08D nutplates which have 32 threads per inch. Did Vans really intend this? Should they have specified AN525-832R8 screws (32 tpi) instead as they do on page 18?
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Sounds like a typo somewhere.

#8 screws are 32 TPI. There may be a Mil Spec for AN525-8R8 and 36 TPI but most likely should have been AN525-832R8 instead of just the -8R8.

The OLD AN525 document says 8-32.
 
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unladenswallow said:
I'm working through chapter 37iS/U (cowling) of the KAI. I've just spotted that on page 16 they call for twelve AN525-8R8 screws which have 36 threads per inch to be screwed into K1000-08 and K1000-08D nutplates which have 32 threads per inch. Did Vans really intend this? Should they have specified AN525-832R8 screws (32 tpi) instead as they do on page 18?
Click to expand...

What Gary said in post #2.

Standard #8 thread pitches are 32 threads/inch (UNC), and 36 threads/inch (UNF). As far as I know, only the only #8 fasteners in an RV are 8-32 (ie: UNC threads).

Pretty sure the drawing callout is a typo.....certainly not one I ever made when creating drawings (OK, not more than once 😬 ).
 
I got my A&P license back when we were using the old AN standard part numbers. Not sure what year but some time around or after the year 2000, all the OLD AN parts got changed to new NASM part numbers. A lot of us old guys that learned the AN part numbers make misteakes with the new numbers.

Yes I spelled mistakes wrong on purpose.
 
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