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Thread sizes

Posted: Fri Aug 16, 2013 3:47 pm
by hdavy
There are plenty of lists which tell you the spanner sizes for most items but do any tell one what thread they are?

Re: Thread sizes

Posted: Fri Aug 16, 2013 6:03 pm
by philthehill
Most engine/transmission parts have UNF threads the rest have BSF threads but recently there has been a tendency for new parts to be given UNF threads. There a few BA threads mainly on the bright work.

Re: Thread sizes

Posted: Fri Aug 16, 2013 8:41 pm
by bmcecosse
Which thread do you need to know...?

Re: Thread sizes

Posted: Sun Sep 01, 2013 9:28 pm
by Tudge
Where are these lists you talk of?! It would be super helpful if you could post up a link of the spanner sizes of screws please! And you are right, a full list of thread types and size of screws for a moggy would be really useful... Is there a way we could start a list on this forum, and then have it added to whenever anyone knows a screw type/size?

Re: Thread sizes

Posted: Sun Sep 01, 2013 9:55 pm
by bmcecosse
Right at the top of this section 'bigginger' made a list for you........ :roll:

Re: Thread sizes

Posted: Mon Sep 02, 2013 4:11 pm
by Tudge
Our prayers have been answered! Better get on fleabay to find a load of whitworth & AF spanners!

Re: Thread sizes

Posted: Mon Sep 02, 2013 4:15 pm
by philthehill
Whilst 'bigginer' has kindly listed the spanner sizes the list does not include the thread sizes i.e. Rocker Cover nuts which are 5/8" A/F spanner size and which have a thread size of 5/16" x 24 TPI UNF and cylinder head studs which are 9/16" spanner size and which have a thread size of 3/8" x 24 TPI UNF and the list goes on.

Re: Thread sizes

Posted: Mon Sep 02, 2013 7:38 pm
by Tudge
No, but it's a start!

Re: Thread sizes

Posted: Mon Sep 02, 2013 9:26 pm
by IslipMinor
Here's a starter for 10 with thread size and spanner size in the same table (and the torque where it is in the BMC Workshop Manual). There are 3 missing that I do not know at all (thread or spanner) without dismantling things:

The master cylinder cap
The differential retaining cap nuts
Track rod ends to track rod

There are also a few thread sizes missing, but the spanner sizes are there.

Please note on both front and rear suspension replacement parts, they can have a UNF thread instead of the original BSF.
Thread and Spanner Sizes Pt1-5 v4.jpg
Thread and Spanner Sizes Pt1-5 v4.jpg (171.18 KiB) Viewed 6367 times
Thread and Spanner Sizes Pt2-5 v4.jpg
Thread and Spanner Sizes Pt2-5 v4.jpg (122.36 KiB) Viewed 6367 times
Thread and Spanner Sizes Pt3-5 v4.jpg
Thread and Spanner Sizes Pt3-5 v4.jpg (152.96 KiB) Viewed 6367 times
Thread and Spanner Sizes Pt4-5 v5.jpg
Thread and Spanner Sizes Pt4-5 v5.jpg (166.48 KiB) Viewed 4242 times
The list is for Series II and Minor 1000 - I have no detailed knowledge of the MM, so will leave that to someone who does!

Comments, changes, additions please!

Re: Thread sizes

Posted: Mon Sep 02, 2013 11:09 pm
by Tudge
Great work Richard, thanks! Is that every bolt & nut in a moggy?! Just missing all the small screws and things...?

Re: Thread sizes

Posted: Mon Sep 02, 2013 11:15 pm
by bmcecosse
Well done Richard! Must have been a quiet day.... :)

Re: Thread sizes

Posted: Tue Sep 03, 2013 7:15 am
by mike.perry
It is no good relying on a list for thread sizes, during production nut and bolt sizes were changed and during a 40 to 60 year life span previous owners will have fitted whatever was available. There are also special sizes where the thread size does not match the spanner size, for instance Series MM engines had metric threads and Whitworth spanner size bolt heads. Thread pitches can be useful but most people would probably not know the relationship between a 20 tpi and a 24 tpi thread.
The best solution is to buy a good set of spanners and sockets. A full set of open enders and some ring or combination spanners as required. A set of combination spanners on its own is no good as a nut and bolt has two ends and a combination spanner has the same size on both ends. A set of A/F spanners from 3/8 to 1 in and 1/4 to 7/16 Whitworth should cover most of your needs. If you have not got a tool don't borrow it, buy it, then you build up your collection and you have the tool for next time.
Now to study Richard's comprehensive list

Re: Thread sizes

Posted: Tue Sep 03, 2013 9:03 am
by MarkyB
Is there a solution to getting it READABLE?
Highlight the contents of the spreadsheet, right click, copy, paste into the thread.
Then it will just be text and as readable as the thread itself.

Re: Thread sizes

Posted: Tue Sep 03, 2013 10:28 am
by IslipMinor
Doing that loses all the formatting and alignment. What I have actually uploaded is a jpeg file of the Excel cells, but for whatever reason, the forum forces the size back to what you see.

Found a work around - reduce the Excel font back to 10, split the spreadsheet cells into 4 groups, create a jpeg for each group and upload them separately. The picture is displayed as the same size as before, but contains less cells so each one is now readable. Previous posting has been updated with this.

Re: Thread sizes

Posted: Tue Sep 03, 2013 10:41 am
by Tudge
Mike.Perry, a very good point, I'll be buying a set of spanners soon... But the list still has its uses - I will be using it to know what nuts and bolts should be there, as opposed to what are actually there. It means I can replace with the correct nuts & bolts.

Now we just need a list of every screw!

Re: Thread sizes

Posted: Tue Sep 03, 2013 11:27 am
by LouiseM
A useful thread (excuse the pun!). Well done Richard - I'll make this a 'sticky' :D

Re: Thread sizes

Posted: Tue Sep 03, 2013 4:02 pm
by philthehill
Richard
Many thanks for the list but what has happened to the list for the front suspension or am I not seeing it?
Rear axle & suspension on the list twice but no reference to front suspension!
Phil

Re: Thread sizes

Posted: Tue Sep 03, 2013 4:55 pm
by IslipMinor
Hi Phil,

Good job someone's on the ball! Obviously not me.

Previous post now corrected - thanks.

Re: Thread sizes

Posted: Wed Sep 04, 2013 3:13 pm
by philthehill
Richard
A couple of details for your spread sheet.
1. The sump plug is 1/2" x 20 TPI UNF.
2. The starter dog thread is 5/8" (15.68mm) x 16TPI (1.75mm). I cannot cross reference in my ZEUS data chart, 5/8" dia threads quoted are either 14 or 18TPI. 5/8" UNF is 18 TPI. I have also tried equivalent metric sizes and still no go. Must be one of those strange/special ISO metric threads? I will look into this further and come back if I find anything.
3. The oil pressure relief valve cover is 13/16" x 14TPI. Again I have been unable to cross reference from the ZEUS data chart. Again strange/special ISO metric thread?
4. The oil pipe banjo nut is 5/8" x 18TPI UNF.
Phil

Re: Thread sizes

Posted: Wed Sep 04, 2013 6:26 pm
by IslipMinor
Phil,

Thanks.

Haven't been able to check the sump plug - engine has oil in it! As has the spare block. Looks like a standard 1/2" UNF then?

Crankshaft front bolt/starter dog is 5/8" x 16TPI, so I would think a 'special' Unified pitch?

The oil pressure relief valve is slightly bigger than 13/16", the one from my spare block measures around 0.824", so that fits nicely with 1/2" BSP, which is 0.825" x 14TPI. I suppose makes sense for an 'oil fitting'?

One more is the banjo bolt for the oil feed to the filter, which is 5/8" UNF.

Have updated the spreadsheet and also the previous posting with all the above.