What thread is this?
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What thread is this?
Hi.
Does anyone know what the thread is where the vacuum pipe screws onto the distributor vacuum unit?
It appears to measure 5/16 x 25tpi, is that a standard thread type or something unique to Lucas?
Thanks.
Does anyone know what the thread is where the vacuum pipe screws onto the distributor vacuum unit?
It appears to measure 5/16 x 25tpi, is that a standard thread type or something unique to Lucas?
Thanks.
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Re: What thread is this?
I dont know the actual answer to your question, but those dimensions are very close to an M8 x 1mm pitch thread which is a standard metric fine size.
Phil
Phil
Re: What thread is this?
Try this link
http://mgaguru.com/mgtech/carbs/cb125.htm
From the above info it is probably a 5/16 BSI thread
I use BSB threads fairly often and the 5/16" thread is 26 TPI so may also be suitable and taps are available
eg https://www.ebay.co.uk/i/253527316673?c ... 578&crdt=0
Taupe
http://mgaguru.com/mgtech/carbs/cb125.htm
From the above info it is probably a 5/16 BSI thread
I use BSB threads fairly often and the 5/16" thread is 26 TPI so may also be suitable and taps are available
eg https://www.ebay.co.uk/i/253527316673?c ... 578&crdt=0
Taupe
Re: What thread is this?
When those units were designed I doubt that Lucas would have even considered using a metric thread
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Re: What thread is this?
Isn't cycle thread 26 tpi ?
John
John
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Re: What thread is this?
In the main - cycle thread has 26 threads per inch.
If not already done so thread gauges applied to the threads to determine the threads per inch (TPI) for imperial threads or distance between threads for metric threads.
If not already done so thread gauges applied to the threads to determine the threads per inch (TPI) for imperial threads or distance between threads for metric threads.
Re: What thread is this?
Re-checking in daylight I think it could be 24tpi which I believe would make it 5/16 unf.
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Re: What thread is this?
A 5/16" UNF thread does have 24 TPI.
To confirm - screw a 5/16" UNF nut onto the threads - if it is right - rotating the nut should require no more than finger pressure.
A set of thread gauges is an absolute must when determining which thread is which.
https://www.ebay.co.uk/itm/52-Blade-Scr ... Sw1JVaMO38
https://www.ebay.co.uk/itm/UNC-UNF-Scre ... SwnHZYmIWZ
It is also helpful to have a copy of the Zeus engineers data-book-charts.
https://www.ebay.co.uk/itm/Zeus-Precisi ... SwUYNaE~rc
To confirm - screw a 5/16" UNF nut onto the threads - if it is right - rotating the nut should require no more than finger pressure.
A set of thread gauges is an absolute must when determining which thread is which.
https://www.ebay.co.uk/itm/52-Blade-Scr ... Sw1JVaMO38
https://www.ebay.co.uk/itm/UNC-UNF-Scre ... SwnHZYmIWZ
It is also helpful to have a copy of the Zeus engineers data-book-charts.
https://www.ebay.co.uk/itm/Zeus-Precisi ... SwUYNaE~rc
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Re: What thread is this?
Agreed, Phil.
But even there can be a problem (for some) of differentiating between 55 and 60 degree thread forms....
But even there can be a problem (for some) of differentiating between 55 and 60 degree thread forms....
Re: What thread is this?
Just tried & a 5/16 unf nut screws smoothly down the threads with no waggle so that must be it.
Thanks for your replies.
Thanks for your replies.
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