Robert72

Hello Explorer42, sorry for taking so long getting back to you. I didn't continue with the restoration, I just decided to use it as is for now. I hope to get back to it at a future date. Now It's time to concentrate on completing my CF spider for my home made tube and get that project completed.

I was just reading up on the Yolo concept, and wondered how the project is going Chriske? Any updates?

I think it probably is a UNC. I am not too au fait with UNC, hence the reason for the post as people with more experience can help. That sounds good as it means i can probably source something. Thanks for all your help!

Well, the good news is I got the broken thumbscrew out, by gluing a nut on it. I may have to go down the drilling and tapping route after all though, unless i can source M5.0 x 1.0.

Looks like M5.0 x 1.0! Anyone know a supplier?

Hello all. I bought a second hand Celestron C8, and the finderscope bracket thumbscrew has sheared. So i ground it down to get rid of the bad thread prior to attempting an extraction, and it turns out it is made of some kind of polymer. Anyway. I am trying to id the thread size. I have tried an M5, but it starts off OK then gets tight, and i don't want to force it. Having said that, the standard screws get tight as well, must be some kind of locking feature. Can anyone tell me what threads these screws typically have, and better still where I can get similar replacements?

OK, so the sub assemblies are pretty much done.... A close up of the spider hub..... The adjuster plate with brass inserts and anodised bolts. I chose red to stand out under red lighting. There is a bigHead female bonded onto the back there to act as a kind of lock nut to resist rotation.... Side view of adjuster plate and bonded bigHead....... Assembled. Still awaiting compression spring....... Internal view of the angle thingy. This is where the spring will go. The bigHead makes an ideal spring rod, but i think i will need a bigger washer...... Candle holders make ideal spider stands........

Here's a trial fit in the building jig....

Now let's make a kit of carbon parts.... I've also made a rudimentary building jig. The outer ring and vanes are held by the adjustable quadrants of MDF. The inner ring is held by the steel dowel. Should be good for holding all the parts in position while bonding.....

Hello, nice project. I was wondering what you were using for your layout drawings? I am also using the Baader Steeltrak in my project, and could do with that dwg for my layout.

Here is the single vane equivalent, it's basically the same however the central box has been replaced with a 40mm tube. The tube and vanes are semi-slotted and bonded. Not sure about the ends, how important are they in terms of diffraction? If need be they can be integrated into the tube, this would give a very clean light path.

I didn't mean the difference between thin and thick vanes, I meant the gap between the vanes. If I read your previous post correctly the gap between the vanes is the thickness of the thick vane. The gap between vanes on my initial design was 10mm. Does that even matter? I think someone in a previous post mentioned if the gap is small it has a larger effect. Regardless, I'm going to have a crack at a single vane design.

Maskulator seems like a handy app. The double vane spacing seems quite small though (I don't know if it makes much difference).

It is 0.25mm sheet - 10mm box at the ends and centre - 0.25mm sheet

Thanks for all your input so far. The main reason for the dual vane design, is that it is so easy to design and build, although I had no idea they were so poorly regarded within the astronomy community. Back to the drawing board!