Taps

[Wagon173]

I'm using somewhat odd size tap and dies on my engine. I'm using a 4 36. I did the tap okay as it gave the drill out size on the package. However I'm having trouble finding a chart with a 4 36 on it. The die cuts a rod that is .112 still or no?

 

[Swifty]

The books that I have only show 4-40 and 4-48, both are .112 major diameter.

Paul.

 

[gilessim]

I have some very old books that were my fathers and I found 4 36 in one of the tables, it gives the OD as .110 .

Giles

 

[Swifty]

Here is a chart showing lots of sizes.
http://www.watchman.dsl.pipex.com/thread.html

Paul.

 

[rhankey]

You can compute the tap drill size with the formula:
Tap_drill_size = Major_size - ( 1 / TPI )

So in your case a 4 36TPI would work out to .112 - ( 1 / 36 ) = .0842", which is midway between a #45 and #44 drill bit size.

Robin

 

[fltenwheeler]

There are over 500 thread sizes in that chart. And I know of some that are not listed.

I do not see 00-90, 000-120, or 0000-160 and it stops at BA 23. I think the BA goes down to 25 or 26.


Tim Meyer

Here is a chart showing lots of sizes.
http://www.watchman.dsl.pipex.com/thread.html

Paul.

 

[Wagon173]

Thanks for the help guys. The equation is definitely getting written down in my tap and die set.

 

[kvom]

Why use such a non-standard size? Fasteners would likely be scarce.