JC
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| posted on 10/11/17 at 02:01 PM |
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1/8 NPT or M10x1?
Hi all,
I have the temperature sensors that came with my Koso digidash. I thought (assumed) that they were M10x1 thread....
Unable to find sensibly priced inline housings in M10, I ordered 2 with 1/8 NPT thread and intended to use adapters from CBS. On a whim, I just tried
the sensors and they fit quite nicely....
Is 1/8NPT very close to M10x1 i.e. could they feel like they fit when they don't?
Secondly, should I use PTFE tape on the thread as per domestic plumbing?
Thanks folks!
JC
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neilp1
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| posted on 10/11/17 at 02:40 PM |
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I'd check with the manufacturer for the correct size is as 1/8" NPT is a tapered thread so you will get a start if it's in M10 but
it wont seal.
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voucht
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| posted on 10/11/17 at 03:02 PM |
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Normally, M10x1.00 is a straight thread, and 1/8NPT if tapered. That should be enough to identify them. Although my hydraulic brake switch (from VW
Beetle) has a tapered M10x1.00 thread, which is very odd and very unusual.
The complete name of 1/8NPT is "1/8x27". The "27" means "27 threads/inch".
M10x1.00 has 1 thread/mm, so 10 th./10mm.
I guess they can feel like they fit when they don't because they are very close to each other. 27 th./inch means 1 thread every 0.941mm.
If you have an accurate caliper, you can measure the distance between 2 threads. If it is exactly 1mm, it is M10x1.00, if it is a little bit less, it
should be 1/8NPT.
Or you can count the number of threads on a 10mm length:
- If it is 1/8x27, you should count more than 10 threads on 10mm, actually, between 10 and 11 threads (10,63 to be exact)
- If it is M10x1.00, you should count exactly 10 threads on 10mm.
I doubt the threaded part of your sensor is long enough to count the number of thread on 1 inch, where you should find 27 threads if it is 1/8NPT and
between 25 and 26 threads (25.4 to be exact) if it is M10x1.00
If your adaptor has a straight thread, a copper washer is enough to seal. If the thread is tapered, you must use Tefelon tape.
Hope that will help 
https://vouchtroadster.blogspot.com/
https://cafrazx550.blogspot.com/
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JC
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| posted on 10/11/17 at 03:53 PM |
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That’s perfect! Best counting glasses on then! Thanks!
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Davedew
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| posted on 10/11/17 at 05:27 PM |
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My Acewell dash came with an 1/8th NPT temp sensor.
Tapped an M10x1.0 hole and screwed it in with some PTFE tape.
Been like that for 3 years on the road and not a single problem.
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russbost
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| posted on 10/11/17 at 05:39 PM |
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The reason Acewell supply 1/8 x 27 npt is that being a tapered thread it is close enough to m10 x 1.0 & 3/8 x 24 that with ptfe tape, it will go
into either & form it's own seal, you are basically doing the opposite putting a straight thread into a (very close in thread pitch) tapered
hole, so, again as long as you use a few turns of PTFE I can't see why it wouldn't seal. If you are going to bother to try & measure
then just measure the thread diameter, m10 x 1.0 is around 9.8mm, 3/8 x 24 is around 9.5mm & the tapered thread should be quite obviously tapered
if measuring with any sort of accuracy at all - you should be able to visually see the taper quite clearly
HTH
I no longer run Furore Products or Furore Cars Ltd, but would still highly recommend them for Acewell dashes, projector headlights, dominator
headlights, indicators, mirrors etc, best prices in the UK! Take a look at http://www.furoreproducts.co.uk/ or find more parts on Ebay, user names
furoreltd & furoreproducts, discounts available for LCB users.
Don't forget Stainless Steel Braided brake hoses, made to your exact requirements in any of around 16 colours.
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NOTE:This user is registered as a LocostBuilders trader and may offer commercial services to other users
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JC
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| posted on 11/11/17 at 05:14 PM |
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Thanks Russ, thanks all!
Amazing how often the bleedin obvious is staring you in the face and it takes the helpful hints on here to make you realise!
I took my calipers to the sensor but used them as paralle guides along the thread and yes, you guessed, its tapered! Problem solved, money saved!
Thanks again - at this rate I might have a running car soon.....
JC
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