Bolt I.D. thread Series No.1: 440 engine
Pipe threads are a whole animal in themselves. there are two types of pipe threads. Straight pipe thread and tapered pipe thread. As the names suggest, straight pipe thread is straight with no taper. The tapered pipe thread has a taper to it sorta like a cork in a wine bottle. It is the taper that helps "plug" the hole.
Chrysler typically calls out a straight pipe thread for the "female" hole. then uses a tapered pipe thread to "wedge" into the straight pipe hole and plug it up.
If you use a tapered pipe thread for the hole, then accidentally tap it too deep, the male thread can go all the way through the tapped hole and fall out the other side because it cannot "wedge" itself in and stop.
Therefore it makes more sense to use a straight thread for the whole and a tapered thread for the "plug". Let the mechanical interference seal the hole from leaking.
Rani, one thing that I noticed is the pipe plug in post #2. Pipe plugs are usually designated by NPT (National Pipe Thread). Believe it is a 3/8 NPT. Pipe is based on inside diameter.
Good informative post. Well done!
Pipe threads are a whole animal in themselves. there are two types of pipe threads. Straight pipe thread and tapered pipe thread. As the names suggest, straight pipe thread is straight with no taper. The tapered pipe thread has a taper to it sorta like a cork in a wine bottle. It is the taper that helps "plug" the hole.
Chrysler typically calls out a straight pipe thread for the "female" hole. then uses a tapered pipe thread to "wedge" into the straight pipe hole and plug it up.
If you use a tapered pipe thread for the hole, then accidentally tap it too deep, the male thread can go all the way through the tapped hole and fall out the other side because it cannot "wedge" itself in and stop.
Therefore it makes more sense to use a straight thread for the whole and a tapered thread for the "plug". Let the mechanical interference seal the hole from leaking.
