SkyWatcher thread size

[Andrew*]

Does anyone know the size of the bolt for SkyWatcher dovetails/tube rings?

Went into B&Q. No can do. It's apparently imperial and they only do metric.

At the same time, can you recommend a supplier?

Cheers

Andrew

[steppenwolf]

I have all SkyWatcher gear and my tube rings (10" , 80mm ST and 80mm ED) are all attached to their respective dovetail bars with standard 6mm thread bolts. The thread on the top of the tube rings is a 1/4" Whitworth (or close enough to make no difference)

[Jaffa007]

Andrew,

I might be able to 'cough' find some imperial (Whitworth) screw's in my parts store at work.

Am sure they won't mind a few being borrowed...... it's not as if they're being used

Let me know what size, head type & length you need & I'll have a look tomorrow.

James.

[Kaptain Klevtsov]

Specifically which bit Andrew? I can measure mine and tell you what the thread size is. I'd be surprised if its not a metric thread as all the threads that I've played with are definitely metric.

Kaptain klevtsov

[Andrew*]

SW, thanks. That probably helps, but 6mm sounds awfully big...

James, very generous (???) of you!

KK, the long Skywatcher dovetail I have has 4 threads and the bottom of the tube rings have the same thread. The thread in the 100ED dovetail is also the same. I have the bolt, but I'm not sure how to measure it. Do I take the largest diameter of the bolt and measure how many threads per inch/cm?

Anyway, the chap at B&Q said it wasn't metric. I tested the thread against all the ones they had there.

Andrew

[brympton]

That's funny, I just had the same problem (last week). Mine was most definitely 1/4" Whitworth a very difficult bolt to find at the right length and in stainless steel. I settled for 3/4" long 1/4" UNC Stainless Socket Screws from here:

http://ccsfasteners.co.uk/unc-14x34-socket-cap-screw-pack-of-4-p-1130.html

These have the same number of teeth per inch (20) but the pitch is about 5 degrees less. Close enough IMHO to not make any difference, long enough to securely bolt down the tube rings and short enough not to go through them (and damage the scope). Hope this helps

Mark

[Macavity]

It is a bit of a minefield, isn't it -I sense M6 or 1/4" BSW, depending on Tube ring size? Occasionally I have chosen to "simplify things", by drilling holes to a common clearance size, then put bolts through - w/heads held (vaguely) captive with superglue . Then, with a LARGE supply of (easily lost!) Wingnuts...

Perhaps not the ideal "field" (cold fingers!) solution tho'?

[steppenwolf]

Hang on a sec chaps!! The Tube Rings are attached to the dovetail bar by pushing a bolt through the UNTAPPED drilled holes in the Dovetail bar and into the TAPPED holes in the base of the Tube Rings. The DRILLED and TAPPED hole in the Dovetail are 1/4" Whitworth but are intended for ataching the Dovetail to a standard tripod mount!

[Tinkerbell]

I Have the long dovetail (33.5cm) that comes standard with the EQ6 Pro in front of me. There are four holes with mounting bolts inserted and between each pair of mounting bolts there are also two more holes. Right putting the mounting bolts into a micrometer the reading shows 4.6mm and the fit in the threaded hole is quite loose so they must be M5's. The other two holes are drilled straight through and accept both M6 and 1/4. The bolts are 22.5mm apart width and 309mm apart length on centers. The other two holes are in the center spine that runs the length of the dovetail. There are no other holes drilled or tapped in the bar and it has just been unwrapped and is brand new.

Hope this is of help.

PS. I also have M4 and M6 fittings and one is way too small and the other too big, funny I don't seem to have any M5 fittings anywhere

[orion f6.3]

1/4 BSW (or AF will do) the threaded pair each end are for your scopes cone error adjustment Orion