DIY - ST80 on SW 200p

[emadmoussa]

Here's the deal....

I'm piggybacking the ST80 on top of SW 200p - To be sure of sturdiness I decided to use a solid piece of wood to be screwed into the rings and then again screw the ST80 in the middle of wooden piece - I want it to act as a dovetail. Those metallic dovetails sold online are unjustifiably expensive for what they are.

I understand you can screw the ST80 into the camera adapter - but at first sight, that doesn't look very sturdy. Here's the plan (attached)

One question though...I don't seem successful getting the right screw size. Does anybody know the size of the ones below...

I want this screw to be longer, yet the same diameter. Also, any idea where to get the black piece alone?

Imad

[emadmoussa]

Sorry ...screws and nuts..

[Bizibilder]

Those screws are 1/4" Whitworth, also known by the American designation 1/4 x 20 (meaning 1/4 inch diameter and 20 turns per inch pitch). Skywatcher are a pain as they mix those threads on some items with M6 which is 6mm diameter and 1mm pitch - almost the same to look at but certainly not interchangeable!! (1/4" is 6.35mm)

[K3ny0n]

Sturdy enough using the dovtail mounting plate, just a thought .

Edit: Didn't read your part about the expensive dovetail, apologies. I've just ordered some aluminium flat bar from ebay, 30mm x 8mm x 600mm long, probably get two peices out of that bar, only cost around £10 incl. postage.

Rob.

[emadmoussa]

Good one. How much did the dovetail cost you?

[emadmoussa]

Duh...sorry, didnt see the price. where did you order it from and which one is it? Thanks, mate!

[K3ny0n]

Edited my post above, I got that one with the telescope. I agree with you regarding the price of the dovetail hence the reason for buying the aluminium bar.

Rob.

[emadmoussa]

Thanks a lot, Rob. Did you drill the holes yourself?

[K3ny0n]

You can get the dovetail bar from FLO for £20.40 not including postage costs, thats for 300mm length, or you can do what I've done and ordered some 600mm aluminium flat bar from ebay which costs around £10 that is including postage and you will get two bars (300m) out of the one aluminium bar.

Thanks a lot, Rob. Did you drill the holes yourself?

I haven't done anything yet mate, waiting for it to arrive.

Rob.

[emadmoussa]

Cool, cheers!

[K3ny0n]

This is what I got mate, http://www.ebay.co.uk/itm/251091982218?redirect=mobile

Rob.

[stevieR]

Im glad i joined this site today. Already saving money. I need to do the exact same thing and the bars are over priced. Thanks for the link k3nyon! I have just ordered mine, cheap guide rings now any suggestions?

[Andymac79]

Im glad i joined this site today. Already saving money. I need to do the exact same thing and the bars are over priced. Thanks for the link k3nyon! I have just ordered mine, cheap guide rings now any suggestions?

Go to a machine shop and get some steel or ally tube off cuts, if they let you root through the scrap bin, even better... Drill them for M4 bolt, weld nuts on ring, put plastic cover on bolt end to protect scope, done.

[Andymac79]

For my finder.

[emadmoussa]

I think Im going to see how the wooden piece goes. Unfortunately didnt get the right screws and nuts yet..

[Andymac79]

Just make sure you get enough tightness on the fixings, and remember that the cold dewy outside conditions may change the wood, causing maybe flex or loosness. Metal is best, aluminium is light and strong.

[stevieR]

Thanks andy, never thought of that. Im a sparky in a a factory ill see some of the fitters tomorrow night maybe they might have something lying about ;-)

[Andymac79]

My mount is covered in 'stuff that was lying about' I have the leg of a puller to counter balance that finder bracket,,

There is a vast scale of equipment on this site. I am most deffo at one end of it !

[emadmoussa]

Just make sure you get enough tightness on the fixings, and remember that the cold dewy outside conditions may change the wood, causing maybe flex or loosness. Metal is best, aluminium is light and strong.

Note taken, thanks, mate!

[emadmoussa]

What can use this piece for???

[Andymac79]

Use it instead of the wood

[emadmoussa]

Use it instead of the wood

I tried it a few minutes ago -- too small, will sit only on one of the rings. I still need longer screws though. But like you say, it could work.

[K3ny0n]

Aluminium came today here is it attached to the ST80, waiting to pick my imaging scope up at the weekend to attach it to the ST80.

Rob.

[dazzauk83]

Replying to the 2nd post in this thread. I only have one of those screws with the black looking washer. Will I need a 2nd one? If so can I purchase them from anywhere? . I work fora fastener company so I could possibly get an alternative . What size screw is it?

Cheers

[laser_jock99]

Nothing wrong with using a stout piece of wood for the top bar- it has a lower thermal expansion coefficient than aluminium!

Wood, Oak 0.0000027 (parallel to grain) Aluminum 0.0000123 - 0.0000129

I used a thick piece of oak to mount a camera on a scope- seemed quite stable.