Villiers C12 thread type

Tagged: Villiers C12

This topic has 8 replies, 6 voices, and was last updated 5 years, 2 months ago by thorbue.

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December 30, 2020 at 4:09 pm #36276

thorbue
Participant

Can anyone help tell me the type of thread on the 5/16 crankcase studs/nuts on a Villiers C12 engine?
One of the studs holding the head has lost its thread, and has no nut right now, so I’ll have to source a new one or make it my self. I believe them to be BSF or CEI but have nothing of this type to test with.

Regards Thor

December 31, 2020 at 5:22 pm #36297

trusty220
Keymaster

All of the Villiers engines that I have worked on have used Cycle Thread (CEI) throughout, which is a constant 26 threads per inch in every imperial diameter.

Best of luck with it, and a Happy New Year!

January 1, 2021 at 9:21 am #36309

charlie
Keymaster

If only one head stud is damaged I would suggest using one of the others with a good thread to establish what the thread is. I have only worked on MK10,12,15 and 25 Villiers engines.

January 1, 2021 at 12:30 pm #36317

andyfrost
Participant

It’s really a case for a thread gauge to establish which rate your engine is fitted with. Villiers used a large array of thread rates , BSC , BSW , BSF very late versions even had UNC/UNF , and to confuse matters many of the magneto threads were BA.

Andy.

January 1, 2021 at 2:05 pm #36318

will-haggle
Participant

At some point in the Fifties British Industry went American, Whitworth, BSF, BA, CEI and a host of other specialised threads went and all new designs were required to have UNF/UNC. This led to the Mini range and some others having engines with BSF/Whitworth types and chassis fittings, having been designed in 1957, using UNF/UNC threads. Then in 1973 it all changed again and we went Metric. Having said all that the one thread in use all over the world to this day is ¼ Whitworth. It is found in the bottom of very camera ever made and on every tripod, good old Joseph Whitworth, specified it in in 1841 and it led to the first National Standards in the world, British Standards. Seems a bit appropriate to be writing this on the day when Britain has left the EU! Not that we’ll abandon the metric system now.

January 1, 2021 at 2:08 pm #36320

will-haggle
Participant

Here’s a link to CEI or British Standard Cycle thread…
https://en.wikipedia.org/wiki/British_Standard_Cycle

January 1, 2021 at 2:37 pm #36321

wristpin
Participant

the one thread in use all over the world to this day is ¼ Whitworth. It is found in the bottom of very camera ever made and on every tripod

It has always struck me as strange that the square drives used in socket sets made in “metric countries” are quoted in quarter, three eighth and half inch sizes etc. They appear to be another accepted international standard for that application.

January 2, 2021 at 8:31 am #36325

charlie
Keymaster

Another example of imperial threads still persisting. My neighbour brought round a fishing rod stand a couple of days ago, which he had managed to cross thread the end piece on. I found it was a BSF thread, I had expected a metric thread.

January 2, 2021 at 8:34 am #36326

thorbue
Participant

Thanks guys.I had UNF, UNC and BSW bolts lying around, they didn’t fit. So I’ll have to source some BSC/REI and try or BSF – These aren’t the most common things here…
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