Threads and Taps

[slug_burner]

One for the fitter or machinists amongst you.

1/8-27 NPT. What tap do you recommend be used to tap a thread to accept a temperature sensor?

OK found that you need a drill size "Q" or 0.332". Now just need the tap

[bee utey]

One for the fitter or machinists amongst you.

1/8-27 NPT. What tap do you recommend be used to tap a thread to accept a temperature sensor?

OK found that you need a drill size "Q" or 0.332". Now just need the tap

I always use 11/32" which works out to 0.344" which ain't far off. Generally most fittings use the larger diameter part of the taper, so I actually cut the first 1/4 inch off my tap so it can do blind/short clearance holes better.

[pibby]

Had to cut one of these last week. The info with the tap recommended a drill of 8.5 mm. I got a kinchrome 24 piece imperial kit for $45 (it was in their brochure) which includes the tap and die for the npt 1/8 27. If you do it everyday not up to the quality but for once in a while it does the job.

as bee utey says, the temp fitting has a tapered thread and so really only uses the top part of the thread you cut.

[Dougal]

Throw the NPT away. BSP is much easier to deal with in this part of the world.

[Bigbjorn]

Throw the NPT away. BSP is much easier to deal with in this part of the world.

BS. Commonly used industrial thread. Used in hydraulics, fuel systems, instrumentation and many other applications.

If you want to cut a proper taper pipe thread of either system, I suggest you get the taper reamer applicable to the size, and the correct size drill, or step drill carefully.

You have no doubt noticed that pipe taps are made short and thick for strength. This is because they receive much use from plumbers, boilermakers, construction workers, farmers, etc who use whatever drill they have and force the tap with a 24" shifter or similar.

[Dougal]

BS. Commonly used industrial thread. Used in hydraulics, fuel systems, instrumentation and many other applications.

Sure it's used in a lot of places, but only to interface with US built or sourced parts.
Just like chain and sprockets, BSP is the standard in this part of the world and all other metric countries.

[slug_burner]

BS. Commonly used industrial thread. Used in hydraulics, fuel systems, instrumentation and many other applications.

If you want to cut a proper taper pipe thread of either system, I suggest you get the taper reamer applicable to the size, and the correct size drill, or step drill carefully.

You have no doubt noticed that pipe taps are made short and thick for strength. This is because they receive much use from plumbers, boilermakers, construction workers, farmers, etc who use whatever drill they have and force the tap with a 24" shifter or similar.

Brian,

Can you PM me with details if you stock these taps and correct drill for them. I am trying to fit some gauges and need the senders which are 1/8-27 NPT to be fitted into the appropriate thread.

[B92 8NW]

Brian,

Can you PM me with details if you stock these taps and correct drill for them. I am trying to fit some gauges and need the senders which are 1/8-27 NPT to be fitted into the appropriate thread.

Let me know how it works out, I think I need the same holes/threads for my VDO crap

[Tombie]

Sure it's used in a lot of places, but only to interface with US built or sourced parts.
Just like chain and sprockets, BSP is the standard in this part of the world and all other metric countries.

Sorry mate but the hydraulics industry is still primarily imperial.

And German metric is often a direct conversion to imperial.

[Dougal]

Sorry mate but the hydraulics industry is still primarily imperial.

And German metric is often a direct conversion to imperial.

The metric system uses British Standard pipe threads, they just renamed them.
Metric G thread is BSPT, Metric Rc thread is BSPF etc.

Which is why the Japanese, Germans, Italians, Aussies, Brits etc all use the same threads. It's only the US out in the cold using NPT threads.