1/2 npt pipe plug what size drill bit???????

[BUDD]

I need to install a 1/2 npt pipe plug into cast aluminum. What size drill bit do I need to use?

Thanks for the help

BUDD

 

[Eric in IL]

23/32

 

[El Toro]

The outside diameter of a 1/2" pipe plug is .840"
a 7/8 drill will be.875" in diameter. There's probably fractional drills that will be closer to the .840". Hal

 

[Anonymous-0]

well for 1/2-14 the size would be a 45/64 drill or size .703 as you are using dissimilar metals make sure you use some anti-sieze on those threads as well. will help in dissasembly later on if needed.

 

[Anonymous-0]

checked another site and it said use the 23/32 I don't know that it would matter much as you have a plus or minus with a gauge because of the taper. in other wise it depends on how deep you tap it. deeper makes the threads bigger the more shallow you tap makes a smaller hole.

 

[ScottyHOMeY]

23/32"

Here's a link
Tap drill tables

 

[El Toro]

If you're needing to know the tap drill size for 1/2'pipe is 23/32 that's been suggested. Hal

 

[Anonymous-0]

Be sure to use a tool to taper the start of the hole to get threads straight and it sure will help starting the tap. I have a 60deg tool in the drill press does great.

 

[ScottyHOMeY]

I can think of a couple times that trick would have saved me a headache or two!

Thanks, Gene.

 

[Vito]

The size is 45/64 as the gentleman already stated.
Vito

 

[teddy52food]

If you have a female fitting use a bit that just goes in. Try it in a thin piece of scrap iron first.

 

[Anonymous-0]

If you want to be precise, the 23/32 would probably be the way to go. But, you CAN get by with a 3/8 drill bit. I've done it. 3/8 would be 24/32, which is only 1/32 of an inch larger. A pipe tap is tapered, which means that the tap gets larger as you screw it in the hole. So, you have to screw it in just a little deeper, when cutting the threads. So, the question is, how precise does this have to be?