1" NPT pipe tap (1- 9/64) or (1-11.5) ?


  #1  
Old 01-27-21, 09:54 AM
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1" NPT pipe tap (1- 9/64) or (1-11.5) ?

Hello question on which pipe tap I should order off of the bay. I'm tapping a steel water well drill bit with a 1" NPT steel pipe (the one from home depot) schedule 40. I ordered this tap from ebay

1 in. -11-1/2 carbon steel npt pipe tap | drill america series qualtech dwtpt

It is too small. I don't know if it was advertised wrong because the ad also said this:

DWTPT1/2

Hand Tool Type: Taps Included Attachments: Pipe Tap Thread Standard: NPT UPC:

705353367281

Individual/Set: Individual Color:

Does not apply

Product Width (in.): 2 Manufacturer: Drill America Product Height (in.): 2 Product Depth (in.): 6 Tools Product Type: Hand Tool Tool Type: Tap Thread spacing: 14 MPN:

DWTPT1/2

Number of Pieces: 1 Measurement Standard: USS
Now I found another 1" tap and that one is 1" NPT 1" 9/64 drill. Which one is the right tap?
 
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Old 01-27-21, 12:17 PM
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A 1x11.5 NPT tap is for a 1 inch nominal pipe size ( schedule 40 is 1.375 OD x 1.050 ID) cutting 11-1/2 threads per inch. A 1.125 drill is used to drill the pipe ID if a tapered reamer is being used. A 1.150 drill is used to drill the pipe ID if a tapered reamer is not being used. I believe you have the correct tap. Drill and/or ream as stated and the tap will cut the threads. Drill deep enough so the tap is not cutting threads into 1.050 ID.
 
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Old 01-27-21, 12:53 PM
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Why do you think itís too small?


 
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Old 01-27-21, 07:32 PM
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wrong tap

I think they sent me the wrong tap. Even thought the listing was for a 1" they must have sent me a 1/2". I appreciate the lightning fast responses. I'm going to return this one and try this again maybe they will send me the correct size this time. I was second guessing myself thinking I ordered the wrong size.

 
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Old 01-28-21, 05:03 AM
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The threaded part in the photos looks like a short nipple, not the end of a piece of pipe. Why are you making threads on the ID when threads exist on the OD. Nipples have a smaller ID than the pipes they connect. I am not a plumber but my guess is the ID of a nipple is not controlled like the ID of a scheduled pipe. I am confused as to what you are trying to accomplish. Please explain.
 
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Old 01-28-21, 07:41 AM
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I'm tapping a steel water well drill bit with a 1" NPT steel pipe (the one from home depot) schedule 40.
I also donít understand (happens to me a lot though Ėlol, so donít think itís you - lol).

Do you mean you want to insert a 1Ē schedule 40 steel pipe into a drill bit, and so you are threading the inside of a pipe which already has external threads and which is connected to that drill bit, so you can then screw in the 1Ē schedule 40 pipeĖ like in the picture?

I think normally instead you would use a female coupling and screw the end of the pipe in the picture into the female coupling, and then screw your pipe into the other end of the coupling.
 
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Old 01-28-21, 09:50 AM
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I think the OP's picture was showing that he got a 1/2" or so tap when he should have gotten a 1" tap. No way that pipe is fitting into the hole threaded with that tap!

(At least not without a much bigger hammer)
 
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Old 01-28-21, 11:18 AM
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A 1x11.5 NPT tap has a diameter of approximately 1 inch at the tapping end. If not, they sent you the wrong size tap. Is that the water well drill bit in the photos? If yes, what is the diameter and depth of the center hole?
 
 

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