Skywatcher tube ring/dovetail bolts?

[Jamgood]

Hi

Can someone tell me which bolts are needed to fit a second dovetail to the top of a Skywatcher 130PDS. I have a second dovetail which has 4 smaller Allen bolts in the ends but what size are the ones in the middle that attach the to the tube ring. From what I can fathom they are M6 bolts but I want to make sure I get the correct ones/size etc.

Hope the image helps explain it. TIA

 

Edited July 3, 2020 by Jamgood

[knobby]

I think they're old fashioned camera tripod top screws, but someone will know for sure.

1/4-20 UNC

Edited July 3, 2020 by knobby

[Helen]

The answer will be whatever screw size you haven't got 🥺   Or you'll have the right thread but they will be too long, or too short, or the head is the wrong size for the countersink... or.... bitter, me??? 

Generally they are 1/4-20 UNC

Helen

[Stuart1971]

If they are not 1/4” then they will me M6. 👍

[John]

I'm pretty sure that the ones on top are 1/4". The camera mount attached to the rear ring in the picture uses a 1/4" screw up through the tube ring and though the knurled wheel. The front tube ring will be the same.

 

[Jamgood]

The threads in the centre of the dovetail bar (first picture) are definitely 1/4-20 UNC. I've used them to attach my camera to it.

It's the bolts in the second image I'm concerned for. I'm not sure if they also are 1/4-20 UNC or M6.  The holes at the end of the dovetail aren't threaded. I've emailed FLO, I'm sure they'll know the answer. Probably been asked a thousand times. 

I don't have the scope at hand to try any bolts as the Scope I received today is boxed up ready to go back. (Damaged item) I just want to get the bolts ready for when the replacement arrives so I can attach the second dovetail.

Thanks for all the replies guys. Appreciated. If anyone knows the answer for sure, shout it out 

 

[AstroMuni]

On 03/07/2020 at 18:54, Jamgood said:

I don't have the scope at hand to try any bolts as the Scope I received today is boxed up ready to go back. (Damaged item) I just want to get the bolts ready for when the replacement arrives so I can attach the second dovetail.

Did you manage to get to the bottom of this? What was the spec?

[Mandy D]

On 15/11/2022 at 10:00, AstroMuni said:

Did you manage to get to the bottom of this? What was the spec?

I just checked on my dovetail bar, which is identical and they are definitely 1/4"-20. M6 will only go in about one turn but my tripod screw goes in easily.

[RT65CB-SWL]

M6 for the end holes (these are not threaded).

M4 for the cone adjustment screws at both ends.

1/4-20 UNC or 1/4” BSW at the centre and offset.