What am I best off doing here?

[phook15]

So I've got a 3/4 copper end cap to house my led and lens holder. It also functions as a blade stop. Now it's going into a 1 inch sink tube so it's going to wiggle around. Am I best off surrounding it in ducktape to center it while I drill and tap it to the of the sink tube or should I let it go off center to the right or left?

[Sevinzol]

Are you sure its a 1" sink tube and not 1.25"? I've seen people use copper end caps for 1" PVC hilts and they fit pretty good.

Led-assembly-for-PVC-hilts This is a good write up for using copper pipe heat sinks.

but if your using a 1.25" sink tube I'd suggest getting 125-Sink-tube-LEDBlade-holder Duct tap is gooey and will compress over time. Try making a metal or plastic collar (bushing) to take up the slack. Or see if a larger copper end cap can be fit into the tube. As far as drilling and tapping go, I would do each operation separately: drill the sink tube, insert the heat sink, mark it, remove it, drill the HS, tap each, then reinsert HS. Sounds like you may be in a bit of a hurry. Take your time. It will be less frustrating.

[phook15]

I've measured the sink tube, it's 1.25 at the bottom but then shrinks down to a little over an inch at the end. I'm talking an inch in inner diamiter

[Silver Serpent]

If it's just a little wiggle room, then I like to use aluminum tape to shim it out a bit. It doesn't compress on you, so it'll stay snug forever. You can pick it up at your local hardware store, typically in the HVAC section.

If it's more than a little wiggle room, you may want to make a collar as Sevinzol stated.