Where to put water temp sensor?

[tirod]

That's an awful big tap. NPT isn't exactly the same as OD thread or root diameter, it's the nominal dimension for the inside of the pipe itself. 5/8" NPT is big - bigger than half inch water pipe. Which would mean adding the wall thickness and threads, too. That makes 3/4 pipe over 1" hole size.

Plus, I'm not sure how available 5/8" NPT is. NPT- National Pipe Thread Taper- ANSI B1.20.1

FWIW.

[patrickt]

I don't know if you're putting Smiths gauges in there, but I think my Smiths sending unit is UNF thread....

[DanEC]

I have a standard water hose nipple that has a nominal diameter of 5/8 inch on the exterior of the threads - but it might actually be sized as something else - I'm not sure. I'm going to take the nipple down to Sears this afternoon and try to match it up against a tap - see if I have any luck. And then if I can match it up I hope the tap notes the size of drill bit I will need.

UNF threads - huh? Well, I guess they generally have screwed into the standard NPT hose nipple manifold opening or there would be a whole cottage industry built up around re-tapping out Ford intake manifolds. I will visually compare the nipple to the sending unit threads and see how they match up. But yes, they are Smith gages.

Thanks

[patrickt]

Originally Posted by DanEC

UNF threads - huh? Well, I guess they generally have screwed into the standard NPT hose nipple manifold opening or there would be a whole cottage industry built up around re-tapping out Ford intake manifolds. I will visually compare the nipple to the sending unit threads and see how they match up. But yes, they are Smith gages.

This page says that UNF threads can only be used with other UNF threads....
McMaster-Carr

[patrickt]

If it was me, I'd call Peter up at Nisonger and ask him just what the deal is with the funky thread. I know he sells his Smiths stuff with your choice of either 5/8 UNF or 3/8 NPT temperature sensor fittings... so it just might make a difference. Certainly worth the price of call before you start carving. Orrrrr, you could do like the rest of us and just jam the threads in good crossways, use a lot of leak-b-gone goo, and torque it down like crazy.

[DanEC]

Originally Posted by patrickt

This page says that UNF threads can only be used with other UNF threads....
McMaster-Carr

I don't think these are a fine thread tapping. I'm beginning to suspect they may just be a standard coarse UNC tapping (non-tapered) opening.

[patrickt]

Originally Posted by DanEC

I don't think these are a fine thread tapping. I'm beginning to suspect they may just be a standard coarse UNC tapping (non-tapered) opening.

Dunno... but all the Smiths stuff at Gauge Guys comes in BSP and UNF. Smiths Classic Gauges

[patrickt]

This is from Caerbont. I think I remember Bob, Peter, or Doug telling me they built the Smiths gauges that were in my car.



Source: Water Temperature Sender