nail a piece of plywood bout 8 inches wide, to a 2x4, so the 2x4 looks like a T with the plywood on top. lock the 2 X 4 in a vise make your plywood about 14" long. take your drill, lay it on its side, on the plywood, chuck facing toward the long end of the board mark 4 holes, drill, on both sides of the barrel of the drill where you marked, and install 2 heavy tywraps or hose clamps (you can add another set of holes straddling the handle to lock it as well below the trigger. ) make sure tied down and locked drill sets level or you might have to shim the thin spots till it is)
find about a 6 or 8" bastard file, with a handle. and a good set of gloves.
first my journeyman would be spinning in his grave if i told you to use a file on alloy but there is a way to do it. have a generous can of spray wd 40.
lock your alloy rod in the drill.
scribe you with lines on the sharpie.
with 6061, before you lock the rod in the drill you can use a tubing cutter to lightly scribe your lines. do not go wider stay slightly under and finish with file.
with the rod setting perpendicular to the board, start the drill . SLOWLY START removing the material as the drill spins, keeping the alloy wet with WD40. top .008 before you get to your inner diameter. and finish to size with strip of cloth back sand paper.
this is a redneck off the cuff way of doing this, BUT it is inherently dangerous. if the file shatters, or the sand strip hangs it will leave a mark.
wear eye protection.
made my cool can out of a old expired air tank(divers) machined a 3" hole in the bottom, leaving enough material for a Oring seat, cut me a 2" thick ring out of 7075, tapped thru 1 3/4 depth with a 3’ 8 pitch BT. ( Tap cost is $914.49) www.regalcuttingtools.com welded it (tig) in place over the cut seat, and then made the corresponding size threaded plug on my atlas lathe cut the bottom for a oring groove, and that part was done, added 3 other welded penetrations, one for a over pressure valve, one for a bleed off cock (SS) and the inlet for the fitting off the hose for my co2 fire extinguisher. I made a small rack for inside that reaches 6" from the bottom of the plug, hang the piece on a wire on that, close and tighten the plug, and flood the tank with co2. let it set appropriate time, before using bleed off valve to drain pressure.
keep in mind, I plugged all but the supply port and had it pressure tested before using
If you cant get your press to work form you ship it to me, and i will trim it on the atlas lathe.