Bedford Taper Thread Query

[Davey089]

Probably a daft question to some . I'm in the process of making some new Rocker cover studs for the MW and the 3\8" UNC thread on the stud is tapered . The query I have is .............. will the thread in the head be parallel ? if I re cut the new stud with a std die will it suffice ? as its not a sealing joint................. or is it :nut:.

 

What's the reason for using a tapered thread for the rocker cover stud ? I thought a std parallel thread would have been sufficient .

 

 

Dave

[john1950]

Try a known parallel thread bolt in the head to see if it locks before bottoming out. Tappered threads will provide a mechanical thread lock for the stud so that the unf nut on the top undoes first.

Edited May 18, 2017 by john1950

[ruxy]

I very much doubt if you in fact have a tapered thread. They look a machine cut thread , so it is just due the short length of thread using a chaser (probably a Coventry Diehead used or such as Kendel & Gent screw machine chasers ) ,,

[Davey089]

Thanks John

 

Try a known parallel thread bolt in the head to see if it locks before bottoming out. Tappered threads will provide a mechanical thread lock for the stud so that the unf nut on the top undoes first.

[Ron]

Are you sure that's a UNC thread? I would have thought more likely to be Whitworth. Same 16 tpi but a different thread form. I would also think that the finer thread for the nuts will be BSF. Just a thought. Ron

[Richard Farrant]

Are you sure that's a UNC thread? I would have thought more likely to be Whitworth. Same 16 tpi but a different thread form. I would also think that the finer thread for the nuts will be BSF. Just a thought. Ron

 

No British threads on a Bedford, all NF and NC

[Davey089]

Thanks for that . I thought it was a taper ,when I held it against a flat it gave me that impression . Reading your response I can see what you mean by a short thread with a chaser . Thanks again

 

Dave

I very much doubt if you in fact have a tapered thread. They look a machine cut thread , so it is just due the short length of thread using a chaser (probably a Coventry Diehead used or such as Kendel & Gent screw machine chasers ) ,,

[Ron]

No British threads on a Bedford, all NF and NC

 

Cheers Richard, you learn something everyday. I've never owned a Bedford. I have a Morris and Austin and loads of other stuff and the only general NF and NC is on my Jeep. Ron

Edited May 19, 2017 by Ron

[Adrian Barrell]

General Motors owned Bedford from 1932, iirc, so much North American influence.