help with thread i.d 1/8 bsp or npt or??

[steveo3002]

ive got a vdo boost gauge that i need to find an adaptor for , vdo seem useless at responding to my request for info

ive searched ebay and find most fitting kits state theyre 1/8 bsp or npt
heres a pic ..its roughly 12mm dia , is it likley its either of those ? anyway i can i.d my thread at home without spending out?

 

[rtbcomp]

Look here under "Technical"

http://www.mig-welding.co.uk/forum/showthread.php?t=15742

 

[steveo3002]

bsp link on that thread is dud

 

[gordon stephenson]

I may be wrong, BUT It doesn't look like BSP or NPT to my old eyes.

 

[steveo3002]

I may be wrong, BUT It doesn't look like BSP or NPT to my old eyes.

is 12mm dia anywhere close to what either of those would be..i really dont have any clue

 

[rtbcomp]

bsp link on that thread is dud

Thanks - I've added a note.

The Duncan-Rogers website has thread data on it.

 

[hotrodder]

Googling BSP thread data will get a chart like this one...http://www.britishfasteners.com/threads/bsp.html same deal for npt.

1/8 bsp is 28tpi, 1/8 npt is 27 tpi and the thread angles differ too. Obviously more useful if you own a thread pitch gauge
NPT is a tapered thread, BSP can be parallel or tapered... the suffix that denotes this is often omitted with the parallel flavour, BSPT denoting tapered
The major dia of tapered threads obviously changes depending where you measure it but neither 1/8 bsp or npt are about 12mm, they're both closer to 10mm- exact numbers will be in the charts

The VDO site ain't great but it lists the various thread sizes available for sensors and kinda does for gauges too. http://www.vdo-gauges.com/instruments.html From the cursory look i've had boost gauges are all 1/8NPT + various adaptors

The towel ain't the best background for looking at threads but i'm thinking the gauge maybe has a metric adaptor screwed in it?

 

[steveo3002]

hmm i can always get another pic , its brand new out of the box thats just a threaded bit with a hole up with a lock nut on

wish id never got it..no bulb holder or nothing with it lol

 

[Tigman]

why dont you take the backnut off and go to your local plumbers merchant and try it on a BSP fitting , if it goes on you have your thread !

 

[Shox Dr]

Where's the font of all knowledge on BSP Threads when you need him

 

[Tigman]

Who`s that then Shox ?

 

[Shox Dr]

Who`s that then Shox ?

You don't know. The thread lasted for long enough

Arrr wondered why I hadn't read any of his crap recenttly :now pre moderated

 

[hareng]

NPT dependant upon length can go 9mm to 11mm dia on male stud.
Can be used for high pressure applications and rely on the threads creating the seal.

BSP differs, the seal is created on the joint often using a Dowty washer.

Piccy from OP doesnt look like an NPT 1/8", its parallel.

Only way to find out is get an accurate diameter measurement and figure the pitch of the thread.
It could be M12X1.5 so a normal M12 nut wouldnt screw on its same pitch as a normal long M10.
http://www.vdo-gauges.com/accessori...x1-5-m14x1-5-m12x1-5-m10x1-and-1-8-28bsp.html

 

[Jester]

To identify a thread of unknown type - 1st check the thread diameter and thread pitch
It will either be metric or English, so measure in inches & mms
For metric, measure between 11 threads then divide by 10 to calculate thread pitch.
For English, count threads per inch ....... full threads, so 15 peaks = 14 threads per inch

Once done, refer to a Zeus chart to see which thread matches your findings
My chart is in the garage (now 2am) ....... if you get the data, I (or others with a zues chart) can id the thread

 

[graffian]

Looking at the ruler and if it's ~12mm I would guess M12x1.5
I would either take a good measument of the thread to find the
pitch, or more likely I would grab an M10 bolt and see if the pitch is the same.

 

[steveo3002]

right it does match a m10 bolt pitch wise ..measure with a cheap vernier its a solid 12mm dia

so sounds about right then...just need to find someone that will actualy sell me the bits now

thanks

 

[Ian Sibbert]

Hi,

All the VDO Boost gauges I have fitted were M12x1.5 with a flat seal rather than a taper seal....

See page from the data sheet...

HTH

Ian

 

[steveo3002]

thanks for that...i dont know why they cant include a scrap of paper in the box telling you whats what

 

[agrimog]

the giveaway is in the manufacturer....VDO... there european---doh. the threads hardly going to be an npt now is it?, every VDO gauge ive ever used has had a metric thread on it, with adaptors to suit whatever you want, unless your buying kit from the USA its very rare you will come across npt threads, and for all you clever clogs out there , there are 3 types of bsp threads , so dont assume its not a bsp cos its not tapered,

 

[steveo3002]

theyre made in usa and europe , ive emailed them and they dont recognise each others products lol

anyone sorted now