Orpington Astronomical Society

Astronomy => Technical => Topic started by: RobertM on Apr 03, 2009, 16:46:12

Title: Anyone got some spare Aluminium approx 1/4" x 8" x 2"
Post by: RobertM on Apr 03, 2009, 16:46:12
Needs to be thick enough to be fairly rigid and able to be tapped for 2ba screws.  Can cut down if oversize so that's not a problem.

Thanks
Robert
Title: Re: Anyone got some spare Aluminium approx 1/4" x 8" x 2"
Post by: Tony G on Apr 03, 2009, 21:34:59
Robert,

I had a few bracket which a few members had, but don't know if anyone used them.
This was the link with the sizes,

http://forum.orpington-astronomy.org.uk/index.php?topic=2355.msg8963 (http://forum.orpington-astronomy.org.uk/index.php?topic=2355.msg8963)

Hope this helps, maybe someone may still have them about the house.

Tony G

Title: Re: Anyone got some spare Aluminium approx 1/4" x 8" x 2"
Post by: RobertM on Apr 03, 2009, 21:40:33
Thanks Tony, they're a but more chunky than I need but I'm certainly not going to turn one down.  Hopefully someone will reply in the next few days.  Quite a useful size that for making mounting bars.

Cheers
Robert
Title: Re: Anyone got some spare Aluminium approx 1/4" x 8" x 2"
Post by: JohnP on Apr 03, 2009, 22:03:55
Robert - I think I may still have mine somewhere.... just don't know where :-( I'll have a look over the weekend & send you an email if I find it....

Cheers,  John
Title: Re: Anyone got some spare Aluminium approx 1/4" x 8" x 2"
Post by: Ian on Apr 04, 2009, 00:39:03
I've got some bits robert, some of Tony's brackets and a strip of 3mm. If you're threading 2BA you should be alright, but aluminium is rubbish at keeping threads, particularly if you plan on taking it apart and putting it back together on a regular basis. I'd be inclined to to use a metric thread and buy a helicoil (or clone) set. I used one on an exhaust stud that I had to drill out, 5 minute job and the result was the business. It's easier than the other approach I took which was to braze brass nuts on the back of the aluminium to bear the load.

just out of interest, why 2BA?
Title: Re: Anyone got some spare Aluminium approx 1/4" x 8" x 2"
Post by: RobertM on Apr 04, 2009, 09:54:39
Thanks guys.  Yes Ian I know Ali is really bad with threads, especially narrow ones, but it's light and should be ok for what I want to use it for.  I already have a metric tap and die set so Ideally all I'd need is 4 small metric screws.  Trouble is I haven't got any - hence the 2BA thing ( I have lots of those).
Title: Re: Anyone got some spare Aluminium approx 1/4" x 8" x 2"
Post by: Ian on Apr 04, 2009, 09:58:53
I've got some m3 and m4 screws if you'd like some of them too. 2BA only just sort of works in metric holes. And the spanners for BA nuts are a really odd size ;)
Title: Re: Anyone got some spare Aluminium approx 1/4" x 8" x 2"
Post by: RobertM on Apr 04, 2009, 11:31:47
Ok, thanks will have those screws as long as I don't have to go to Wormwood Scrubs to pick them up ;)  just need the plate now.
Title: Re: Anyone got some spare Aluminium approx 1/4" x 8" x 2"
Post by: Ian on Apr 08, 2009, 10:59:54
are you ok to wait until the next meeting or would you like to pop round and pick some up?
Title: Re: Anyone got some spare Aluminium approx 1/4" x 8" x 2"
Post by: RobertM on Apr 09, 2009, 08:21:34
Thanks Ian, if you could PM me your address then I'll pick them up - tonight if that's ok?

Cheers