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andydeans3
V4 Guru

United Kingdom
1174 Posts

Posted - 07 Mar 2019 :  23:30:07 Show Profile Reply with Quote
I've had my boot lid off to paint the inside, and fill the cavities with wax.
I stupidly didn't run the nuts on to the captive bolts, when I took them off......you can guess the rest. I've lost 2.

I thought I had nothing better to do than go through my extensive "nut and bolts" store and find another couple. Nope, M8 runs on a thread or so, and locks up. Same same some UNF nuts I have, so I now assume that the thread is UNC.

Spent an hour at my mates house in the village, going through his various nut/bolts supply...nope.

Am I correct in saying it is UNC? if so what size? It could be 5/16" UNC, since an M8 seems to be the roughly the right diameter, and 5/16" is 7.9 mm. Though with the daft imperial system, the nominal size is not always the actual diameter. I know for a fact that a 1/2" NPT thread is about 3/4" OD!

I'm sure I can get some from Wrights, but need to be sure of the thread.

As an aside, why did a continental company like SAAB use imperial bolts sizes on the bodies of their cars?

1978 LHD SAAB 96
1978 MGB Roadster
2008 LHD "Classic" Renault Twingo
1991 Nissan Figaro

greg124
V4 Fan

United Kingdom
157 Posts

Posted - 08 Mar 2019 :  00:51:58 Show Profile Reply with Quote
Hi Andy,
definitely UNC, looking at my spare boot lid I'd say 5/16.
If you're stuck I can send you four,

Clive

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V4saab1966
V4 Beginner

United Kingdom
98 Posts

Posted - 08 Mar 2019 :  01:13:03 Show Profile Reply with Quote
Hi Andy
Ive a few of these if you need any
Cheers Paul
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melle
V4 Guru

United Kingdom
2747 Posts

Posted - 08 Mar 2019 :  08:21:18 Show Profile Visit melle's Homepage Reply with Quote
quote:
Though with the daft imperial system, the nominal size is not always the actual diameter. I know for a fact that a 1/2" NPT thread is about 3/4" OD!
Unified (UNC/ UNF etc., 60 degree thread form) and Whitworth (BSW/ BSF etc., 55 degrees) thread sizes are always nominal, just like metric. NPT is a pipe thread that shares its thread form with UN (BSP, which is more commonly used in the UK, has the same thread form as W), but confusingly uses the internal pipe diameter to identify the size.

UN spanner/ socket sizes are measured across the flats ("AF"), just like metric. Whitworth (not used on our cars) uses the nominal thread diameter to identify the size, so W spanners and sockets are always bigger than their size suggests. In order to save material, Whitworth heads were downsized 1 size (1/16") at some point, the newer system is called British Standard. BS and W spanners/ sockets are interchangeable, but as a result of the change, BS tools for the same nominal head diameter are always sized 1/16" up from their W equivalents. With an adjustable spanner you certainly can't go wrong!

www.saabv4.com
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andydeans3
V4 Guru

United Kingdom
1174 Posts

Posted - 08 Mar 2019 :  11:14:22 Show Profile Reply with Quote
Melle.
You are a fount of knowledge sir!.

VSAAB66 and Greg124
Thanks for the offer guys, but I may have found a couple with a local SAAB man here in Fife. He just texted me.

This forum is truly amazing!

1978 LHD SAAB 96
1978 MGB Roadster
2008 LHD "Classic" Renault Twingo
1991 Nissan Figaro
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Dynorog
V4 Fan

United Kingdom
130 Posts

Posted - 08 Mar 2019 :  17:41:40 Show Profile Reply with Quote
Melle,
That was an excellent concise overview of thread types.
I didnt know about the W downsizing.
Cheers

Dynorog
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andydeans3
V4 Guru

United Kingdom
1174 Posts

Posted - 08 Mar 2019 :  18:15:30 Show Profile Reply with Quote
Melle

Problem with using the ID of the pipe, on NPT is that the ID changes with the pressure rating.

An NPT fitting rated at 10 000 psi, does not have the same wall thickness of one rated at 3000 psi.

I've ordered some UNC nuts from Wrights.


Andy

1978 LHD SAAB 96
1978 MGB Roadster
2008 LHD "Classic" Renault Twingo
1991 Nissan Figaro

Edited by - andydeans3 on 08 Mar 2019 18:17:01
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72sonett3
V4 Fanatic

Spain
246 Posts

Posted - 08 Mar 2019 :  18:16:58 Show Profile Reply with Quote
quote:
Originally posted by andydeans3
Melle.
You are a fount of knowledge sir!

Yes, even more amazing as he grew up with the metric system!

Anyway, when Brexit is a fact you can all go back to Imperial...

I think the 96 was the last Saab model with imperial hardware, the 99 was all metric.

--
'72 97
'77 96L conv.
'79 96GL (LPG)
'83 900i (LPG)
'95 900SE conv.
'99 9-3T
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72sonett3
V4 Fanatic

Spain
246 Posts

Posted - 08 Mar 2019 :  18:20:27 Show Profile Reply with Quote
quote:
Originally posted by andydeans3
Melle.
You are a fount of knowledge sir!

Yes, even more amazing as he grew up with the metric system!

Anyway, when Brexit is a fact you can all go back to Imperial...

I think the 96 was the last Saab model with imperial hardware, the 99 was all metric.

--
'72 97
'77 96L conv.
'79 96GL (LPG)
'83 900i (LPG)
'95 900SE conv.
'99 9-3T
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andydeans3
V4 Guru

United Kingdom
1174 Posts

Posted - 08 Mar 2019 :  18:21:06 Show Profile Reply with Quote
You are certainly correct about Melle.

In relation to the wee quip about Brexit - the whole world with a few exceptions like the US, use the metric system, it's got nowt to do with this Brexit nonsense.

In all my travels, and they were very, very extensive over 37 years, the only place I can ever remember visiting that used the old silly system, was the US, and maybe an island in the Caribbean......

Back in the nineties, I was involved in teaching oilfield stuff to a delegation of Chinese engineers, and was warned at the outset to not even mention things like feet, inches, psi etc. Metres,( and sudivision of), Kilopascals for pressure etc etc. ONLY.

Andy

1978 LHD SAAB 96
1978 MGB Roadster
2008 LHD "Classic" Renault Twingo
1991 Nissan Figaro

Edited by - andydeans3 on 08 Mar 2019 19:05:08
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72sonett3
V4 Fanatic

Spain
246 Posts

Posted - 08 Mar 2019 :  21:26:33 Show Profile Reply with Quote
quote:
Originally posted by andydeans3

... the whole world with a few exceptions like the US, use the metric system

Yes, the USA is a weird place...

--
'72 97
'77 96L conv.
'79 96GL (LPG)
'83 900i (LPG)
'95 900SE conv.
'99 9-3T
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melle
V4 Guru

United Kingdom
2747 Posts

Posted - 08 Mar 2019 :  21:26:59 Show Profile Visit melle's Homepage Reply with Quote
quote:
Originally posted by andydeans3
Problem with using the ID of the pipe, on NPT is that the ID changes with the pressure rating.
That may be a problem, but it certainly isn't my problem. ;)

quote:
Originally posted by 72sonett3
Yes, even more amazing as he grew up with the metric system!
I work on stuff with all kinds of threads and a few years ago I got fed up with not understanding the different systems, so I did some studying. The basics are not too hard to understand by the way, see my previous post.

I have spanners and sockets for Metric, Unified, Whitworth/ BS, and hundreds of taps and dies for Metric, UNC/UNF, BSW/BSF, BSP, NPT, BA, ME, Brass, BSC (cycle thread) and specialist and more exotic thread types. Lots of my metrology gear (micrometers etc.) and the best part of my workshop literature are old and Imperial. The Machinery's Handbook makes for great bedtime reading if you're a nerd like me!

quote:
Originally posted by 72sonett3
I think the 96 was the last Saab model with imperial hardware, the 99 was all metric.
I think the first 99s with the 1.85 engine were imperial?

Andy, I usually buy my fasteners from Kayfast, they're also on eBay.

www.saabv4.com

Edited by - melle on 08 Mar 2019 21:28:55
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deggsie
V4 Fanatic

United Kingdom
327 Posts

Posted - 08 Mar 2019 :  23:51:47 Show Profile Reply with Quote
quote:
andydeans3
As an aside, why did a continental company like SAAB use imperial bolts sizes on the bodies of their cars?

Ah, Andy - it's all because of your alnar, fot and tum !
In a similar way to old biblical measurements (like the cubit and span etc) and old Scottish measurements (like the ell), Swedish measurements were based historically on standardised anatomical lengths (ooer, missus).
The Swedish aln (like ell = forearm, plural 'alnar') was standardised in 1863 at 59.37 cm (1.948 ft).
Half an aln was historically a 'fot' and 1/12 of a fot (2.474 cm) was a 'tum' (thumb or inch), but the 1863 'decimalisation/standardisation' sought to change the tum to 1/10 of a fot (2.96 cm).
Swedish mechanics and carpenters refused to accept this change and arbitrarily switched instead to the Imperial inch (2.54 cm) the use of which survived until late in 20th C. There were even hybrids in the wood trade, where it was necessary to buy eg. 'four by two' by the metre !
Bet you're sorry you asked !!

___________________________
Saab - beyond the conventional !

Edited by - deggsie on 08 Mar 2019 23:53:47
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andydeans3
V4 Guru

United Kingdom
1174 Posts

Posted - 09 Mar 2019 :  10:11:11 Show Profile Reply with Quote
Deggsie
Aye, and then there's the Scandinavian "mile", which is a slang term for 10 kms, so beware of a Norwegian telling you it's it's 10 "miles" to the next town. He means 100 km, ie 62 miles!!!

The French and Germans use the word "pound", livre in French or pfund in German, as a slang term for 1/2 a kilo.

Andy

1978 LHD SAAB 96
1978 MGB Roadster
2008 LHD "Classic" Renault Twingo
1991 Nissan Figaro
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72sonett3
V4 Fanatic

Spain
246 Posts

Posted - 09 Mar 2019 :  10:21:59 Show Profile Reply with Quote
The scandinavian "mil" not "mile" = 10 km, also Dutch had the "pond"= 500 g.

--
'72 97
'77 96L conv.
'79 96GL (LPG)
'83 900i (LPG)
'95 900SE conv.
'99 9-3T
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deggsie
V4 Fanatic

United Kingdom
327 Posts

Posted - 09 Mar 2019 :  11:08:35 Show Profile Reply with Quote
Indeed, it's a whole 'container of invertebrates' ...

I'm assuming that classic Volvos have the same issue ??

PS Still seeing the following on posting messages "An error occurred on the server when processing the URL. Please contact the system administrator.

If you are the system administrator please click here to find out more about this error."

And very slow loading of the forum pages.

___________________________
Saab - beyond the conventional !

Edited by - deggsie on 09 Mar 2019 12:40:54
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