Which bolts??

[Kylee]

I am putting together my imaging kit and have purchased a couple of Skywatcher dovetail plates and the Skywatcher guidescope mount, none of which come with the bolts!

I have looked on a number of forums and seen suggestions but thought I would get some confirmation if anybody knows. The thread is slightly larger than standard bolts and have seen "Whitworth" bolts mentioned.

Can anybody help?????

[JonH]

Yep they are whitworth, can't remember the size though. Closer to bloody wood screws than bolts! Quite why they use a thread like that I don't know! Will be a pain to find and expensive when you do!!
I drilled and tapped mine out to M6 and added a load more while I was at it....

[Carole]

It beats me why they can't supply these things with bolts in the first place.  I have even had a set of guide rings with a different thread to the dovetail plate!!!!

Carole

[JonH]

It beats me why they can't supply these things with bolts in the first place.  I have even had a set of guide rings with a different thread to the dovetail plate!!!!

Carole

I had similar with tube rings and dovetail bars with different threads!

[Carole]

I had to get some-one to tap the thread for me.  PITA.

Carole

[JonH]

I changed all mine to M6, would it be so hard for them to have some kind of standard on their parts?! It would make life easier for us and probably cheeper for them!
I mean really, pretty much no one uses Whitworth anymore!

[mickw]

Yep, its 1/4" Whitworth which is a very common thread - most stuff in USA and cameras, try cramming a 6mm bolt in the tripod hole - it will not be happy 

Here's one of several places to buy them, if you hunt around you can also get countersunk
http://www.imperialnutsandbolts.com/fasteners-and-fittings/socket-head-cap-screws-12-9-self-colour/bsw-whitworth-socket-head-cap-screws-12-9-self-colour/1/4-bsw-whitworth-socket-head-cap-screws-grade-12-9-self-coloured/prod_555.html

[Rick]

1/4"W is THE standard for camera mounting. Even my little point-n-click Canon has a quarter-whitworth hole in its base.

[JonH]

1/4"W is THE standard for camera mounting. Even my little point-n-click Canon has a quarter-whitworth hole in its base.

You sure it's not UNC? Whitform but not Whitworth....

[MarkS]

Apparenetly Whitworth was the previous standard and UNC is used now.  But they're similar enough to be compatible.
http://en.wikipedia.org/wiki/Tripod_(photography)

With so much camera and tripod history it would be lunacy to change it now.

[mickw]

Very interesting, I've always known it was Whitworth in cameras - it seems I was wrong  

Extract from Wikipedia

Nearly all current still cameras accept a 1/4" UNC thread in their tripod baseplate though the UNC is close enough to Whitworth that it will fit, and many motion picture cameras accept a 3/8" UNC and, again, the Whitworth is close enough to fit, while a 5/8" UNC thread is the accepted standard for tripod mounted land surveying equipment and, once again, the Whitworth will fit

But I was close enough not to care  

[JonH]

Yea they are close enough, so long as they were made in china....
I can promise you though if the threads were actually cut to tolerance you would soon see the difference!

[mickw]

If the threads were cut to tolerance, the chinese ones would soon beat them into shape 

[JonH]

Indeed there are many things in life a little leverage can fix 

If I so much as joked about using a Whitworth bolt in a UNC threaded part at work they would never let me near flight hardware again! 

[mickw]

 

So you don't work on Garuda stuff then