Grantura nuts & bolts

[bazjude2998]

Struggling a bit ,sure I,ll get the answers.Can anyone give me the correct size and threads of the nuts to suit the studs top and bottom shock absorbers mounts Grantura Mk 11a
Thanks in anticipation

[plasticpig72]

I suggest you find a "Zeus" booklet with thread tables + Imperial Thread pitch gauge + Vernier Caliper.
The Thread Pitch gauges sometimes come with a set of Taps and Dies.
A Thread File is also handy to remove any burrs or damage.
Alan

[bazjude2998]

Thanks for information.They are 1/2” BSF

[phillpot]

bazjude2998 said:

Thanks for information.They are 1/2” BSF

My money would be on 1/2" UNF (20 tpi). That is certainly what TVR used on many later models.

1/2" BSF is 16 tpi, not a problem so long as you have the matching nuts

[bazjude2998]

Thanks.They are 16 TPI .Thought at first they were metric. And way back Mr Whitworth was striving to standardise these frigging things

[plasticpig72]

I don't think they will be BSF, they will be Unified either UNF or UNC.
Be careful because UNF and BSF have the same pitch except for 1/2" dia.
But Unified are 60° and BS 55°. BS or Whitworth went out with the Arc.
Alan

[bazjude2998]

Thanks Alan,I have double checked and the upper 1/2” studs are BSF 16 tpi ( on my car 1962)

)
1/2”UNF are 20 tpi
1/2” UNC are 13 tpi
Thanks for all help Regards Baz

[Granturadriver]

What shocks do you want to use in future?

Do they have the same seize/diameter in their upper and lower bushes?

[bazjude2998]

Hi Martin,I have a set of Spax Krypton Gas ready to fit.The upper & lower bushes are the same size although the nut size on the lower stud is 3/8th as opposed to 1/2” upper.The lower stud is 1/2” turned down,hope that makes sense and helps.To add I,m no expert on the Grantura so really not sure whether this set up is standard.Any other information or comments from yourself or the Gurus,much appreciated
Regards Baz

[Dollyman1850]

I think once the triumph parts bin was adopted by TVR then the AF standard of UNF and UNC was pretty much adopted. Early cars though (Wilkinson cars) were very much from a British engineering perspective and BSF BSW are all common threads to be identified and found very much on early Granturas up to the MK3.

The American standard filtered through a bit later... Its funny but I once read a book where Keith Duckworth was quoted as discussing some very high tensile thread applications for rolled threads and our American friends had come up with a course metric design to provide the specs required.. Keith Duckworth commented that some resourceful old UK engineers must have had some very good skills back in the day because the new thread was pretty much the same as an old Whitworth thread... another Northern first Stockport I believe


N.

Edited by Dollyman1850 on Wednesday 15th November 21:09

[GAjon]

And to go completely off topic,

General John Sedgwick who unfortunately has become a person noted for their famous last words,

“They couldn’t hit an Elephant from there”

Just before being shot dead was killed by a bullet from a Whitworth Rifle.

[bazjude2998]

Never thought this post would create so many THREADS.Thanks to all

[Dollyman1850]

GAjon said:

And to go completely off topic,

General John Sedgwick who unfortunately has become a person noted for their famous last words,

“They couldn’t hit an Elephant from there”

Just before being shot dead was killed by a bullet from a Whitworth Rifle.

Good old Joe. Also the man credited with inventing the Thou!
N.