Good idea with the coupling. To add a bit more mass, set the coupling on a flat metal table top, melt doen a few wheel weights, and pour an inch or so of lead into the bottom of it. The cane I carry has about a pound of bullet casting lead poured into the tip- - - -sort of an "attitude adjuster" for somebody who thinks they're picking on a crippled-up old man!
Jerry

"It is better to be silent and be thought a fool than to speak and eliminate all doubt!" - Abraham Lincoln
Cringe and wail in fear, Eloi- - - - -we Morlocks are on the hunt!
There is nothing noble in being superior to your fellow man; true nobility is being superior to your former self. - Ernest Hemingway
Love your enemies and drive 'em nuts!