What size drill bit do I need for 1/4 inch pipe thread?

NPT Tap Drill Chart

Tap Size Drill Size Tap and Drill Set
1/4″ NPT Tap 7/16″ Drill Bit 1/4″ NPT Tap and Drill Set
3/8″ NPT Tap 37/64″ Drill Bit 3/8″ NPT Tap and Drill Set
1/2″ NPT Tap 23/32″ Drill Bit 1/2″ NPT Tap and Drill Set
3/4″ NPT Tap 59/64″ Drill Bit 3/4″ NPT Tap and Drill Set

What is the tapping drill size for 1 ⁄ 4 BSW thread?


5/32 32 4.37
3/16 24 5.16
7/32 24 5.95
1/4 20 6.75

Is BSP the same as G 1 4?

Is G thread the same as BSPP? The two types of thread are the same parallel straight. BSPP is the British Standard Pipe Parallel thread and it is also denoted by the letter G (ISO standard). Therefore, BSPP is the same as G.

Is BSP the same as BSPP?

BSP stands for British Standard Pipe technical standards. BSP connection includes two types of threads, one is BSPP which can be straight or parallel; the other one is BSPT, which is tapered. The thread pitch and thread angle is the same 55 degree. BSP and BSPP is not the same thing.

Is G thread same as BSPP?

BSPP = British Standard Pipe Parallel, cylindrical pipe thread with 55°apex angle. British parallel threads are often referred to as “G” threads, the two types of thread are the same parallel straight, the threads are measured in threads per inch. Therefore, BSPP is the same as G.

Is BSP same as BSPP?

Does BSP come in metric sizes?

Although BSP is a foreign thread, it isn’t metric. This is why it comes in imperial sizes: 1/8, 1/4, 1/2, 3/4, and so on. Pitch & diameter measured in inches e.g. G1/4-19

Can a male BSPT thread into a female BSPP?

It is possible for a male BSPT (tapered) to thread into a female BSPP (parallel), so long as the female thread is fixed and not swivel (this is because of the recessed cone seat on the BSPP end). You must find the I.D. to determine the threads per inch count for BSPT fittings. Simply obtain a caliper reading from inside the bore of the fitting.

What is the thread form of British Standard Pipe?

British Standard Pipe (BSPP, BSPF) Thread Form r = Basic Radius = * 137329 p h = Basic Depth of Thread = *640327 p p = Pitch = 1/t.p.i. (Threads per Inch) ISO 228, DIN 259, BS2779, JIS B0202 In Japan this thread is known as (PF) Use prefix G for parallel thread. Example: G1/2