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