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Does 3/8" NPT fit M10x1?!?! (Zetec)
Mave - 22/7/05 at 06:37 PM

I'm looking for a T-piece, to fit an oil gauge to my Zetec, while continuing the use of the oil pressure warning light.

Now I have found several shops which offer T-pieces, but my oil gauge has a thread of 3/8 NPT, and all the T-pieces have either 1/8 NPT or M10x1.

I have a regular VDO oil gauge, so why can't I find a suitable T-piece? Or does 3/8 NPT fit M10x1?

Marcel


givemethebighammer - 22/7/05 at 07:19 PM

try Burtons

http://www.burtonpower.com

they seem to have most stuff like this. I think I bought my tee piece from them. Like you I have a VDO gauge and sender, I can't remember the thread sizes though.


Humbug - 22/7/05 at 10:00 PM

or here: www.lma-group.com/motorsport/Products/Gauge_Fitting_Parts/gauge_fitting_parts.html

3/8" nptf is not the same as M10 x 1.0


DarrenW - 25/7/05 at 08:18 AM

I was recently looking for some M10 x 1 bolts to fasten prop to rear diff flange. Non of the imperial similar sizes were close enough. I had to buy proper bolts from Ford.

Im fitting DD2 to my car (Pinto engine). Oil pressure warning light sender replaces std ford sender. I have to get an adaptor to replace the oil gallery plug to fit the oil temperature sender so i can get an oil temp feed to the gauge. Is this an alternative idea? The new oil pressure sender has two connections - one for the pressure warning light and the other for the pressure gauge. It is a neat solution and i think they are available for sale seperately on ETB website.

[Edited on 25/7/05 by DarrenW]


NS Dev - 25/7/05 at 08:24 AM

quote:
Originally posted by Mave
I'm looking for a T-piece, to fit an oil gauge to my Zetec, while continuing the use of the oil pressure warning light.

Now I have found several shops which offer T-pieces, but my oil gauge has a thread of 3/8 NPT, and all the T-pieces have either 1/8 NPT or M10x1.

I have a regular VDO oil gauge, so why can't I find a suitable T-piece? Or does 3/8 NPT fit M10x1?

Marcel



Right, lets sort this out!

The 3/8" measure you talk about (if it is similar in size to M10x1) will NOT be 3/8" npt, it will be 3/8" UNF.

3/8" unf is basically the same thread as 1/8" NPT, except that the npt is tapered for a seal on the threads. the "1/8" bit refers to the BORE of the pipe that it is used to connect, in the case of the unf thead, this is the thread major diameter (i.e. the OD)

So, in short, 1/8npt and 3/8 UNF will screw together, but will need some method of sealing.

3/8" unf does actually screw into M10x1 (but not the other way around) which makes things more confusing, but if you try and tighten it it will strip the threads!


Mave - 25/7/05 at 03:47 PM

Aha, thanks for the response. You seem to know about threads alright.

But.... the package of my sender says it's 3/8-27 NPT. Could you tell me if this fits either 1/8" NPT or M10x1?
(hmmm, I must say I find this pretty confusing.....)

Cheers,
Marcel


Alan B - 25/7/05 at 06:22 PM

quote:
Originally posted by Mave
Aha, thanks for the response. You seem to know about threads alright.

But.... the package of my sender says it's 3/8-27 NPT. Could you tell me if this fits either 1/8" NPT or M10x1?
(hmmm, I must say I find this pretty confusing.....)

Cheers,
Marcel


Sounds like a misprint...I think should read 1/8-27 NPT...which is neither M10x1 or 1/8BSP or 3/8UNF...all are similar but none are interchangeable.


Alan B - 25/7/05 at 06:26 PM

quote:
Originally posted by NS Dev

3/8" unf is basically the same thread as 1/8" NPT, ........


Er..it isn't

Sure the thread angle is the same but 3/8 UNF is 24 TPI and 1/8NPT is 27TPI....any thread engagment can only be minimal and for limted number of turns..


Mave - 25/7/05 at 07:15 PM

Hmmm, it's even more complicated than I thought......

To make things even more complicated; in the package there were also three adapters. According to the package it was supposed to be just one: 3/8"-18NPT to 1/2"-14NPT.
All three adapters in the package have a different outer diameter/thread. But they all fit the sender perfectly with the inner thread! Sooooo, does that mean the sender is 3/8"-18 NPT?!?

Is there any way I can determine the size without having a thread caliper thingy?


Alan B - 25/7/05 at 08:44 PM

If the outer diameter of the sender is about 5/8" then it could easily be 3/8-18NPT


NS Dev - 25/7/05 at 09:35 PM

you're quite right, have PM'd Mave with the error!

I have bodged these together before, but with brass fittings...............Doh!

Sorry, my error! (I hate giving wrong info!)

Only answer is an adaptor.......

Just read your post again, here's the correct answer!

No it won't fit, you need an adaptor, part number FBM2138 from Think Automotive in London, which is a male to female adaptor, 3/8nptf to 1/8 nptf. £4.11 each.

[Edited on 25/7/05 by NS Dev]


Mave - 26/7/05 at 07:56 PM

Thanks.
I've send an email to Think Automotive and am waiting eagerly for their response.
{edit}:
According to Think Automotive, the outer diameter of 1/8 - 27NPT is 13/32" and the outer diameter of 3/8 - 18NPT is 11/16".

Also note that the 27NPT is indeed for the 1/8. Soooo, combining all this info, the only conclusion I can draw, is that Alan is right, and that the manual has a misprint. I must have the 1/8-27 NPT. And can use a normal T-piece!

Thanks again, and a big thank you for Think Automotive for the rapid response!

Marcel


[Edited on 27/7/05 by Mave]