I wish I hadn't ....!!

[FlashDrive]

Me and my perfectionist attitudes ....why can't I just leave things alone :(


I was not happy ( at first I was ) with the paint job on my Astro Royal 76mm Tube ...looking closely at the tube I became critical of my work.


So...off came the Lens and focuser...back to wet and dry the tube for another paint job.


In the process of drying the tube with a soft cloth .... I dropped it on the concrete and damaged the thread at the Lens end.


I tried in vain to sort a solution to fix this .... eventually I ' cut out ' the damaged portion of thread, and with a very thin 3 point file carefully went about restoring the area to clean the thread from where I had removed the bad bit.


So many times I tried to screw the Lens back on, and it would not.


I kept it as parallel to the tube every time ...it would turn and then go cross threaded.


In the end I have rendered the threaded end completely un-usable, it's only fit for the bin.


I'm now left with a lovely 76mm f/16 Lens and a good working focuser.


Col....

[multiweb]

You could cut the tube past the damaged thread.

[LewisM]

There are certain things that make my stomach drop...this being one of them :( So sad to see Col.

It's fixable - but it's going to take some effort and likely a long bed lathe with centering support. I am certain you could find a machine shop to do it.

One thing I learned years ago with restorations regarding paint - let it dry a MINIMUM of a month before doing ANYTHING to it. Epoxy paint seems better, but car acrylic rattle cans are hopelessly bad. Dulux Metalshield epoxy is fantastic (I leave it 2 weeks before touching it) and their Duramax rattle cans are also very durable.

[LewisM]

I think Col already has.

This really is a simple fix on a long bed lathe.

[FlashDrive]

Yep ....I thought about sourcing 76mm x 2mm Aluminum Tube and getting a new thread put on it...but no baffles in the tube.

Anyway, the tube is in the bin..

I'm considering putting up the Lens and focuser in the classifieds.

Col...

[LewisM]

Col, seriously, take it to a machine shop! It's a SIMPLE FIX

[FlashDrive]

The tube is beyond repair ....

[SkyWatch]

So sorry to hear that Col. I have just been arguing with some painting of a tube too...
Perhaps you could try what Bill Bradfield (the famous comet hunter) did with a 90mm objective. See attached! ;)
I particularly like his lens cap (second image). - And the eyepiece (a 25mm Kellner) is jammed into the end of an old vacuum cleaner tube...
All the best,
Dean

[JA]

Sorry to hear about your scope Col. I doesn't seem entirely beyond repair, especially if that image is the current state of the tube, or was that taken just post damage but before repairs?

It's hard to say without seeing it from all angles, but a wooden inside form and a wooden exterior form might be of some use in straightening the tube/thread without too much crush damage, followed by judicious use of a triangular file to finesse the thread, etc.

Failing that you could cut away part or all of the damaged thread and have a low profile threaded end collar made to fit over (or possibly inside) the slightly shortened original tube (the original tube with thread cut off). That way you could maintain the original tube with baffles, etc, if what is shown is indeed the only damage.

Best
JA

[FlashDrive]

Thanks everybody for your thoughts on this matter.

Col...

[N1]

Contact IIS member Joshua Bunn. I'm pretty sure he'll be able to fix that quite easily (by making an adaptor, for instance). His rates are very reasonable.

[FlashDrive]

Thanks :)