How hard is it to build a telescope?

[gooseholla]

So I learned a useful and valuable lesson tonight: when deviating from the lengths of metal rungs stated in the K+B book, make sure you compensate for it when drawing out the plan for how to cut the plywood. Had I of taken these measurements to the cutters, my mirror box internal size would have been 10mm too small, as my rungs are rounded up from the K + B figure, and I forgot to add the two side length thicknesses in to my original calculation! Pays to triple check calculations to save time and money. Fortunately no wood had been ordered or cut!

[estwing]

Good luck hope it goes to plan!!

[gooseholla]

Thanks everyone for the kind wishes and those who have helped me get this far already.

It has been such a learning experience already and I have learned how to do so much in this short space of time, and overcome problems. Can't wait to see what this next 3 or 4 months brings. Hopefully a decent scope that works!
 

John

 

[gooseholla]

Not much progress today. Aluminium turned up for the triangles. Waiting for my neighbour to have a spare moment to cut it nicely.  Also made one of the split bolts to hold the mirror support strap.

Primed and sprayed the connecting bars for the triangles black today. Tomorrow I hope to build the frame for the cell, and then I will mark out where the holes are to go. Then it might be a few more days before anything happens as I have uni work to be getting on with over the weekend.

John

[gooseholla]

Flotation triangles

Today my neighbour cut the triangles for the mirror flotation device. They are 6mm Aluminium ones. Because they were cut freehand they need a bit of filing to make them straight, but they don't actually look too bad in person. He has also got his drill press up and running so I can now mark out all the holes and have them drilled, and hopefully by the weekend the entire frame will be welded and all the hardware attached to it.

[Sfarndell]

Looking good John!

What did your neigbour use to cut 6mm aly with? I'm making my cell too and I'm not convinced about a jigsaw. Yet.

[gooseholla]

He used a jigsaw. It made light work of it and cut pretty straight when he was paying attention. I originally marked the trianlges in permanent marker, but we then scribed them up for the blade to follow in a channel. Hence why some of them have marker on which seems miles off - we redrew them all.

I stacked them all together for filing and only a couple are a bit wonky. I'm not too worried, no one is going to see! However, the metal on the jigsaw base scratches the ally up something rotten. Since it is going to have a mirror on top, again I wasn't too fussed. But it is worth considering finding someone with a bandsaw or guillotine cutter if you want it perfect.

[Sfarndell]

Thanks John.

Function over form. No-one is really going to see the call and as long as it works well, it doesn't matter.

[gooseholla]

Indeed. I try my best with my ability and tools to make a good job. But at the end of the day, if it needs cutting and its the only way to cut it, it has to be done!

[swamp thing]

Just a tip. Use masking tape on the foot of the jigsaw to prevent scratching the ally or cover the area to be cut with it.

HTH

[gooseholla]

Excellent tip.

I forgot to add. During a moment of staring into space at a local DIY store today, I finalised the prototype design of my secondary spider. The vanes are going to be modified T hinges, as the metal is thin but strong and the right shape for spider vanes - also handily comes pre-painted matte black. The hinge part is too big, but that will be removed and a bit of the vane bent and screwed to a block of plywood which will house the 3 collimation bolts. From this a few circles of plywood will hang with a large metal surface on top for the collimation bolts to ride against. Then a 45 degree angle will be added for the mirror to eventually bond to.

[Horwig]

I'm late to the party!!!!!!!! Good to see another home scope build.

Another vote for John Nichol, a true gent, his optics are superb.

My 16" Newtonian took me a few years to build, but it was well worth it and I still have the scars (literally) from the build.

Don't be tempted to hurry the build and don't build too much before the mirrors arrive, I mocked up my trusses in plastic overflow pipes to check focus before cutting the carbon fibre tubes, and lucky I did, my calcs were out by 30mm.

Don't be too proud to farm out specific bits to experts to help you out, you are still driving the build, even if others have their fingerprints on bits of it.

John made my mirrors, a local firm did the intricate metal cutting on a water jet, and a local fabricator did all the welding and the powder coating on my scope and mount.

I could have gone out and bought the whole thing off the shelf, but where would the fun have been in that.

Best of luck with your build.

Huw

[gooseholla]

Well today my neighbour drilled all the holes in the metal meaning after lunch I can build a welding jig for it.

They were done using a drill press last used in 1947 on a sheep farm in Romney Marsh. We had the giggles watching this thing trying to drill. It did a good job once all the settings were tweaked.

John

[gooseholla]

This afternoon I mocked up a frame for welding.

I will recheck all the angles and lengths are correct before my mate welds it all together.

John

[gooseholla]

Hi,

Looking for a bit of advice. The three mirror supports in the K + B to stop it falling out in transport are basically 3 bolts covered In a bit of plastic. I don't like the looks of them. I was thinking of using wooden dowels with a small disc of wood on top, but presumably they'd have to be thicker than the metal bolt solution K + B offer? I feel their solution spoils the look of the tailgate.

Any advice welcome!
John

ps Neighbour getting his welding stuff ready so hopefully this weekend the tailgate will be ready, bar 3 mirror supports.
 

[swamp thing]

John I used mop stick handrail. The flat allows accurate indexing for positioning. If you'd like a pic give me a shout or check my build thread.

Edit: if you want a link give me a shout

HTH

[gooseholla]

Hi,

Just googled it. Like the idea, not too keen on having to buy 3m of the stuff though! Is there a source that sells only 30 cm of it?

Thanks

John

[swamp thing]

You should get mop stick in 1.8m lengths from all 'good' timber merchants.

[gooseholla]

Bingo. The timber yard where I will be getting my plywood from sell it for £2.75 + VAT a metre.

Cheers.

John

[gooseholla]

So, exciting times today. MY neighbour welded my frame together, I will post pictures when it is cleaned up, primed and painted.

Also, I placed an order with John Nichol for an 18" 1/8 F4 mirror! Let the fun begin... in 10 - 12 weeks!

John

 

[Horwig]

I feel the onset of clouds already!!

Huw

[gooseholla]

Funny you say that, was clear this morning, order the mirror, raining here!

[estwing]

Great move ordering from John you will not be disappointed

[gooseholla]

Well, it has been a learning process and a half, but my metal frame is finally ready for all the bits to be assembled. It was welded by my next door neighbour, an ended up about 1mm out of square still, but hey, who is going to worry! Been primed and will be painted black at a later date. The paint and primer has come from the pound shop. Primer there is still plenty left, so I don't think I will be needing the two cans of black matte I purchased, but at £3 the lot, cannot complain.

Nuts have been securely epoxied onto the metal on both sides for the collimation bolts.

Considering I'm not a professional and never done anything like this before, I think it has turned out alright!

I shall say what I said a while ago - get metal pre-cut or find someone with the correct tools to do it! It isn't much fun cutting metal and trying to straighten it up with a hacksaw and file! Split bolts are also a nightmare to make, buy some if you value your hands and sanity!

I'm looking forward to doing some wood working now, and devoting my attention to making a secondary spider, that should be interesting.

[mapstar]

Good progress there John and well done up to now.

Respect for ordering from Nichol optic I will be contacting him myself for some more advice on my mirror grind very soon I think

Keep up the enthusiasm

Damian