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Imperial Thread Close to M8 ?
dhutch - 1/7/10 at 12:51 PM

Whats the thread on a ford english diff going to be? Its nearly m8 but clearly not!

Also, on the same topic, does anyone have a list of imperial thread sizes with their norminal dimention in metric as well. Otherwise im going to make one.


Daniel

02GF74 - 1/7/10 at 12:53 PM

5/16 UNF (approx 7.9375 mm)

Metric threds come in variety of pitches so if the diameer is the same, the pitch may not be the standard one but fine thread.

The bolt head, if imperial usaully has bars stamped to identify the type - the info. about this and more is out there on the web.

[Edited on 1/7/10 by 02GF74]

dave - 1/7/10 at 12:55 PM

There's an imperial palace near the M8 in Glasgow.

dhutch - 1/7/10 at 01:04 PM

quote:
Originally posted by 02GF74
5/16 UNF (approx 7.9375 mm)

Metric threds come in variety of pitches so if the diameer is the same, the pitch may not be the standard one but fine thread.

Studs done appear to have any markings.

It could be M8 fine (1mm) rather than the more common M8 course (1.25mm) but i dont think it is. 5/16 UNF is 1.058mm, 5/16 UNC 1.4mm pitch

Daniel

[Edited on 1/7/2010 by dhutch]

smart51 - 1/7/10 at 01:50 PM

quote:
Originally posted by dhutch
5/16 UNF (approx 7.9375 mm) ... M8 fine (1mm) ... 5/16 UNF is 1.058mm,


So you could accidentally bodge an M8 Fine nut onto a 5/16 UNF thread?

David Jenkins - 1/7/10 at 02:00 PM

It'll go a half turn or so, then jam.

02GF74 - 1/7/10 at 02:19 PM

quote:
Originally posted by dhutch
Studs done appear to have any markings.



ok, so you are talking about the studs on the diff. I am sure I replaced the nuts on mine, just cannot remember the size.

If you have a nut, thenimperial nuts are taller than the metric ones - not sure that is 100% bulletproof rule but that is what I found on more than one occasion.

britishtrident - 1/7/10 at 02:55 PM

5/16" UNF --- diff housing to casing.

5/16" UNF Propshaft to small size diff flange (Mk1 Escort, Mk1 & Mk2 Cortina Mk1 Capri )

5/16" UNF on retainers for Wheelbearings/Halfshaft/brake back plates.

[Edited on 1/7/10 by britishtrident]

escary - 1/7/10 at 07:15 PM

if the thread looks like a metric pitch it could be unc and not unf you'll see a difference straight away.

there is definately some unc on my ford parts but some are from a mk1 escort and could be 40 years old

regards

Ewan

scudderfish - 1/7/10 at 07:28 PM

http://www.locostbuilders.co.uk/viewthread.php?tid=116467

5/16 UNF was my finding

[Edited on 1/7/10 by scudderfish]

dhutch - 1/7/10 at 09:18 PM

quote:
Originally posted by britishtrident
5/16" UNF --- diff housing to casing.

5/16" UNF Propshaft to small size diff flange (Mk1 Escort, Mk1 & Mk2 Cortina Mk1 Capri )

5/16" UNF on retainers for Wheelbearings/Halfshaft/brake back plates.
quote:
Originally posted by scudderfish5/16 UNF was my finding

Sounds good to me.
- Better get a bit of a stock of 5/16th UNF nylocs then!
- I changed the propshaft bolts to M8, which 2k miles later seems fine.


Daniel

dhutch - 1/7/10 at 09:20 PM

quote:
So you could accidentally bodge an M8 Fine nut onto a 5/16 UNF thread?
I guess it might go, certainly a half nut might be on with a chance.
- But metric fine is amost as uncommon as UNF so you gain little!

Mark G - 1/7/10 at 09:45 PM

Don't know if it will help but there's a good iphone app called bolt & nut where you place your bolt on the phone and match it to the thread on the screen. Very handy if you need to find a thread. Also tells you the size of a nut or bolt head when put on the screen, also has info about screw heads, bolt markings etc.