rethreading a tripod mount

[neil_g]

any engineers in the house?

i have a fubared tripod mount thread on one of my bits of kit. now im thinking about getting it helicoiled (drilled, tapped and threaded insert fitted).

after a lot of googling and searching there seems to be a lot of debate over whether it is 1/4-20" or a whitworth, more lean towards being 1/4-20".

if so would this be the one?

http://cgi.ebay.co.uk/Helicoil-Type-Thread-Repair-Unified-UNC-1-4-20-TPI_W0QQitemZ310093265543

 

[mick m]

Neil, the link is for a UNC set, 1/4 x 20 tpi (teeth per inch). What I would do is have a look here http://stainlessmiddleton.co.uk/hex unc page.htm they do whitworth as well, and buy one of each bolt too see which one fits the best. Then you have a bolt you can cut to make a stud for the fitting and know which helicoil set to buy.
The only difference is that the thread pitch/angle is slightly different between UNC and Whitworth.

Mick.

 

[classcams]

I went the whole hog and bought a 1 metre length of whitworth studding 1/4" 20.

 

[HoppyUK]

Standard tripod bush is 1/4in Whitworth.

 

[neil_g]

right so whitworth IS 1/4x20?

 

[swanseamale47]

Theres also a larger 3/8th whitworth (not used much now) if it's the female thread thats stripped you may be able to get it drilled out and tapped, then silmply change the male for the older larger size (check if it's available first though)
the only problem then is nothing much else will fit it.

 

[neil_g]

okay cool, i'll speak to dad when he's back from holidays and see if he has any helicoils in that size.

cheers guys, hopefully this will work out cheaper than sending it off.. lol

 

[neil_g]

although saying that the manufacturer has just replied to my email regarding them fixing it and theyve said to send it in and they "will see what they can do for you"..

do i spy a freebie?

 

[photon]

Just to confirm: standard tripod bush is 1/4"x20 BSW (British Standard Whitworth).

BSW has a thread angle of 55°, whereas UNC is 60° with flattened crests to the male threads, which reduces the strength somewhat but gives more clearance, allowing use of less than ideal components in less than ideal conditions e.g. World War II.