On Mar 26, 2:29*pm, Robin wrote:
I'm working on a little project (a spotlight) that is basically a bit
of aluminium tubing, 50mm ID, 5mm wall thickness. I was wondering the
best way to close the end of the tube that doesn't have the light
shining out. I'm hoping to make it water resistant

a) Turn a round plate of 60mm diameter, drill and tap the tube and
screw the plate on - problem being the wall thickness isn't that great
so I'd be limited to about M3

b) Cut an internal thread in the tube and a threaded plug to fit
(probably a 1.5mm ISO thread) - would require some form of sealant/
threadlocker

c) Cut a chamfered plug and bond it to the tube - not sure what
adhesive to use

Any other ideas? I'll be using my Myford Super 7 and indexable tools

You've about covered your options except for spinning. A little late
to plan for that. If you're using any sort of high-temp incandescent,
like halogens, it'll cook any sort of adhesive. Heat expansion may
loosen pressed components.

Any reason for making one as opposed to buying one? Around here,
there's any number of cheap track lights about that size at the big-
box home improvement places. Most of those are cast units. Can even
get LED bulbs for those now.

Stan