- Thread starter The Coal Man
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cardiffrob
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Have a S-10 1994 model that have happily sprinkled in Metric heads with Imperial threads and Imperial heads with Metric threads.
Mad Metric? Metric heads on Whitworth threads. Just when you thought it was all beginning to make sense....
http://www.mg-cars.org.uk/imgytr/pdf/madmetrics.pdf
Mad Metric? Metric heads on Whitworth threads. Just when you thought it was all beginning to make sense....
http://www.mg-cars.org.uk/imgytr/pdf/madmetrics.pdf
The_Yellow_Ardvark
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Cobbler
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The Coal Man
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There is no obvious shallow recess on the top of the head. The thread guages should arricv in a day or two so hopefully that will provide a bit of clarity.
Rgds
rosinante
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AFAIK imperial nuts and bolts have heads that may be very close to metric sizes but would probably have a correct imperial spanner often marked with the bolt thread size ,ie 1/4 ,5/16 whit, across the flat sizes often given numbers ie 75 af is 3/4 inch ,also imperial sizes often include spanners sized in 32nds of an inch,when I was landrovering I searched for these odd sizes in boot sales etc
Whitworth and ANC threads have included thread angle of 55 deg unified threads have 60 deg thread angles some Whitworth threads will fit unified coarse if the tpi is the same,
The Royal family have imperial nuts
Chris
Whitworth and ANC threads have included thread angle of 55 deg unified threads have 60 deg thread angles some Whitworth threads will fit unified coarse if the tpi is the same,
The Royal family have imperial nuts
Chris
ronan
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You can go back to proper imperial measurements in the uk now you have had breakfast, errrr brexit. No more of those pesky germans and french and their confusing logical metric.
Bill Edwards
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Metric bolts have the tensile strength in numbers, such as 8.8, 12.9 etc. Imperial stuff has a domed recess and three, five etc lines for tensile strength.
But, you're almost as well to throw this knowledge out of the window because these days imperial stuff can have metric markings - it's all a nightmare where only a set of verniers and a thread gauge can help.
With head sizes (which aren't to be relied upon) some of them are noticeably different - e.g 1/2 is actually tighter than 13mm, 9/16 is slacker than 14mm, 3/4 is slacker than 19mm and so on. But some (5/8 - 16mm) are very, very close.
But, you're almost as well to throw this knowledge out of the window because these days imperial stuff can have metric markings - it's all a nightmare where only a set of verniers and a thread gauge can help.
With head sizes (which aren't to be relied upon) some of them are noticeably different - e.g 1/2 is actually tighter than 13mm, 9/16 is slacker than 14mm, 3/4 is slacker than 19mm and so on. But some (5/8 - 16mm) are very, very close.
rosinante
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Yup , gonna go and buy a yard of 50 x 25 mm timber, and have 568 cl of ale , oh and a gallon of fuel, so I can work out mpg on my 2000 cubic centimetre diesel engined car,it is rated at 90 horse power, does this mean my grocer won't get prosecuted for selling me a pound of tomatoes?, would have quoted you roan but dunno how yet,
Chris
Chris
Bill Edwards
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Just click 'Reply' at the bottom right of their post, then type your message underneath the text which appears in the box you write in.
rosinante
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Bill Edwards
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Well done! Not everyone realises to press enter before typing to space things out better.
The Coal Man
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Update:
The thread gauge arrived today. After a test, the only one that fits is the Whitworth 12, an 11 (3/8) does not fit and a 13 does not fit.
Having said that, the gauge I bought only covered metric and Whitworth, it dod not cover any other thread types.
On the basis of the above, the bolt appears likely to have a Whitworth 1/2" thread at 12tpi. I will buy a few and see how they fit the clamp.
I was not able to test for ANC or UNC due to the absence of gauges on the thread gauge set I bought. I suppose to categorically exclude ANC I should buy more gauges?
Rgds
The thread gauge arrived today. After a test, the only one that fits is the Whitworth 12, an 11 (3/8) does not fit and a 13 does not fit.
Having said that, the gauge I bought only covered metric and Whitworth, it dod not cover any other thread types.
On the basis of the above, the bolt appears likely to have a Whitworth 1/2" thread at 12tpi. I will buy a few and see how they fit the clamp.
I was not able to test for ANC or UNC due to the absence of gauges on the thread gauge set I bought. I suppose to categorically exclude ANC I should buy more gauges?
Rgds
rtbcomp
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BSF (and probably Whitworth) have letters, R is high tensile, S is higher still.
If there are no markings play safe and assume they are mild steel. Special bolts & screws with no markings may still be high tensile. These will be most likely machined.
Bill Edwards
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As far as I can see UN and BS can be checked with the same thread gauges. They're both measured in tpi and the thread angle is near enough identical so to identify a thread measure the OD and pitch then look it up in all the charts for BSW, BSP, UNC and UNF and you'll find the match.
