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Is 1/8th NPT the same as M10x1?
matt.c - 19/4/09 at 09:33 PM

Need to order my sender unit for my water temp guage so can you help? ^^^^^^^^^


vinny1275 - 19/4/09 at 09:35 PM

Don't think so, NPT are tapered threads iirc....

Cheers


Vince


JoelP - 19/4/09 at 09:35 PM

i believe not, on the basis that google says you can buy adapters between them. May well be wrong though...


owelly - 19/4/09 at 09:39 PM

1/8" NPT has 27 threads per inch and 10mmx1 has 1 thread per mm. So no. They're not the same!


matt.c - 19/4/09 at 09:46 PM

oh dear what the feck do i do now!


AdrianH - 19/4/09 at 10:24 PM

1/8th NPT is as posted above 27 TPI with a taper. I ended up making an adapter myself after some messing around for my brake system.

For use with temp gauges there are adapters, what thread is on the temp gauge?

You could have a browse on here.
http://www.earls.co.uk/earls/index.html
or
https://www.europaspares.com/INSTRUMENTS/SENDER_ADAPTORS,_ETC/


Adrian

[Edited on 19-4-09 by AdrianH]

[Edited on 19-4-09 by AdrianH]


BenB - 19/4/09 at 10:29 PM

Get an adaptor as mentioned above???


hicost blade - 19/4/09 at 10:40 PM

I hope its your sender which is the 1/8npt bit because all you need to do is run an 1/8npt tap into to the M10x1 hole, it will open it out and cut it perfectly.

M10x1 and 1/8npt are almost exactly the same pitch and the small end of the 1/8npt taper is almost an exact match to the M10x1, the tap will just wind in without any cross thread at all.

Don’t go too far though, there is nothing like a sloppy taper!

Don’t use ptfe either as the sender will not earth properly (thread lock works a treat).

Job done.


mad4x4 - 20/4/09 at 06:43 AM

YOu should n;t be using PTFE or thread lock on an NPT thread .

NPT is an interference Fit therfore creates a metal to metal seal.


Liam - 20/4/09 at 12:33 PM

The hydraulic engineer in me is shuddering!

Standard NPT is not a sealing thread and should be used with a sealing tape/compound. The NPTF derivative is a sealing thread.

And 'adapting' NPT to metric with a tap - eek! We occasionally mate NPT to BSP at 1/2" and 3/4" where the pitch is the same, but it's still a temporary get-out-of-jail-free bodge.

Your cooling system is critical and operates at an appreciable pressure - I'd recommend getting the correct fittings/adaptors and doing it properly.

Sorry that's not in true locoster spirit

Liam


hicost blade - 20/4/09 at 04:30 PM

Sorry to be augmentative but

M10x1 to 1/8npt is easily done without a 'bodge' and has been 1,000,000's of times by 1,000,000's of people.

But I do agree 1/8npt to M10x1 is


MikeRJ - 20/4/09 at 05:34 PM

quote:
Originally posted by Liam
Your cooling system is critical and operates at an appreciable pressure


It would take an exceedingly poorly made thread to fail at the 15PSI or so that cooling systems run at.


hicost blade - 20/4/09 at 05:36 PM

quote:
Originally posted by MikeRJ
quote:
Originally posted by Liam
Your cooling system is critical and operates at an appreciable pressure


It would take an exceedingly poorly made thread to fail at the 15PSI or so that cooling systems run at.


Agreed


minitici - 20/4/09 at 05:41 PM

If you need an 1/8 NPT tap - they are sometimes hard to find and can be expensive - do what I did and but a complete tap and die set which includes the 1/8 NPT tap - all for less than one tap!
e-bay link

I needed one to tap the R1 5VY oil cooler bolt for an oil pressure sender.