Orpington Astronomical Society

Astronomy => Telescopes Etcetera.... => Topic started by: Kylee on Dec 03, 2012, 20:52:18

Title: Which bolts??
Post by: Kylee on Dec 03, 2012, 20:52:18
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?????
Title: Re: Which bolts??
Post by: JonH on Dec 03, 2012, 22:01:49
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....
Title: Re: Which bolts??
Post by: Carole on Dec 03, 2012, 22:55:14
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
Title: Re: Which bolts??
Post by: JonH on Dec 03, 2012, 23:21:52
Quote from: Carole on Dec 03, 2012, 22:55:14
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!
Title: Re: Which bolts??
Post by: Carole on Dec 03, 2012, 23:39:48
I had to get some-one to tap the thread for me.  PITA.

Carole
Title: Re: Which bolts??
Post by: JonH on Dec 03, 2012, 23:45:52
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!
Title: Re: Which bolts??
Post by: mickw on Dec 04, 2012, 06:10:11
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 (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)
Title: Re: Which bolts??
Post by: Rick on Dec 04, 2012, 14:41:02
1/4"W is THE standard for camera mounting. Even my little point-n-click Canon has a quarter-whitworth hole in its base.
Title: Re: Which bolts??
Post by: JonH on Dec 04, 2012, 15:13:52
Quote from: Rick on Dec 04, 2012, 14:41:02
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....
Title: Re: Which bolts??
Post by: MarkS on Dec 04, 2012, 16:36:37

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.
Title: Re: Which bolts??
Post by: mickw on Dec 04, 2012, 16:46:33
Very interesting, I've always known it was Whitworth in cameras - it seems I was wrong  :oops:

Extract from Wikipedia
QuoteNearly 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  :P
Title: Re: Which bolts??
Post by: JonH on Dec 04, 2012, 16:56:25
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!
Title: Re: Which bolts??
Post by: mickw on Dec 04, 2012, 17:17:52
If the threads were cut to tolerance, the chinese ones would soon beat them into shape  ;)
Title: Re: Which bolts??
Post by: JonH on Dec 04, 2012, 17:27:31
Indeed there are many things in life a little leverage can fix  :lol:

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!  :-?
Title: Re: Which bolts??
Post by: mickw on Dec 04, 2012, 18:19:57
 :lol: :lol:

So you don't work on Garuda stuff then  ;)
Title: Re: Which bolts??
Post by: JonH on Dec 04, 2012, 18:26:46
Erm....no, the stuff I make tends to spend its time at a slightly higher altitude than actual flight.  :lol:
Title: Re: Which bolts??
Post by: Kylee on Dec 04, 2012, 23:39:43
!/4" UNC...that's what I've ordered!!! Fingers crossed!