Thread type: UNC or UNF?

Joe_SP

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Hi all

I am currently restoring a classic car, a 1961 Warwick. I want to buy some replacement nuts and bolts but I am confused by the thread types. I know it is not metric so it must be UNC or UNF. Does anyone know the differences and the type it is likely to use.

Thanks in advance.

joe
 

kjay

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Hi all

I am currently restoring a classic car, a 1961 Warwick. I want to buy some replacement nuts and bolts but I am confused by the thread types. I know it is not metric so it must be UNC or UNF. Does anyone know the differences and the type it is likely to use.

Thanks in advance.

joe

All I know is ( I think) that NC = national course and NF = national fine.

So I'd guess at UNF ??

.
 

W210 Fan

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UNC is unified thread course and UNF is unified thread fine chances are most stuff will be the course which is standard, like metric stuff the most used is course, can I suggest you get a thread book with metric/imperial thread info and drill sizes like a Zeus book thats full of lots of great info

http://cgi.ebay.co.uk/ZEUS-BOOK-BRA...3286.c0.m14&_trkparms=66:4|65:2|39:1|240:1318
 
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Joe_SP

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Thanks all.

If F = fine, then it is most likely to be UNC as the threads are nothing like as fine as Metric fine.

I gues it wont matter as long as I get matching nuts and bolts?
 

W210 Fan

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Thanks all.

If F = fine, then it is most likely to be UNC as the threads are nothing like as fine as Metric fine.

I gues it wont matter as long as I get matching nuts and bolts?

agreed, be carefull though, some threads will go together but be wrong as they are too loose, or go in a few threads and the bind up, a cheap electronic vernier or set of thread guages will stop this happening,

http://cgi.ebay.co.uk/LCD-Digital-C...286.c0.m14&_trkparms=66:4|65:15|39:1|240:1318
 

Harley Man

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I think its most likely that the threads on your 1961 car are BSF and Whitworth rather than UNF/UNC, certainly BSF/Whitworth was used in the british bike industry (Triumph/BSA) until 1968, they then slowly introduced UNC/UNF. The easy way to tell is by what size spanners fit the nuts and bolts - UNC/UNF sizes are AF spanners and BSF/Whitworth use BSF/Whitworth spanners.

Some BSF/Whitworth and UNC/UNF threads are the same dia and pitch but the thread angle is different 55degrees for BSF/Whit and 60degrees for UNC/UNF.

David
 

Ted

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iI'd go with Harley Man (despite his poor choice in bikes :) )

Now try getting Whitworth spanners!!! (totally different to AF or metric)
 
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Joe_SP

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That is good advice, the spanners are definitely AF.

I do have a set of Whitworth spanners I bought for my fathers 1933 morris 10/4. That turned out to be mainly metric!
 

verytalldave

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Smaller nuts/bolts/screws could be BA. Largest size is 0BA which is about 4mm diameter across the thread. Smallest goes right down to 12/14BA which are tiny. Usually found holding the trim and electric bits together.
 

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