Joining aluminum and sainlessl?

I am going to make a fairly large fishing gaff from some of my extensive
scrap box. Trying to keep it as light as possible I have selected 4' of
6061 1" aluminum tube for the handle and formed some 5/16" 316 rod for
the hook. The plan is to machine two aluminum bushings. One a slip fit
into the tube at the end of the shank and a second as the hook exits the
tube. The bushings will be pinned to the tube but I can't figure the
best way to tie the hook to the bushings.
I have never had success with brazing or soldering stainless and
aluminum. If I pin them I will be reducing the steel right where the
stress is highest. Only thing I have come up with is to drill the
bushings for a tight interference fit, heat them and slip them on the
hook before they cool. Any other suggestions?
Reply to
Glenn Ashmore
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Glen, First, I would replace 6061 with 5000 series, if it is in your scrap box. Second, I would use 3/8" not 5/16", as I think it'll bend to easy in use. That said, I have been successful using a shouldered bushing matching the ID and OD of the aluminum tube made with mating SS with that of the hook. I would drill the bush for the rod and TIG it in place at both ends of the bush. Then with a light press fit, first coating both the ID of the tube and OD of the stainless bush with permanent Lock-Tite. After the Loc-Tite sets, drill and tap 2 holes on both sides, one high one low on the bush 1/4-20 and countersink for, 4 flat head SS screws. Use never-seize when assembling. I have used this technique before for other items very successfully. It is amazing the strength of Loc-Tite. Steve
Reply to
Steve Lusardi
In addition, larger gaffs usually have a ring welded or forged as part of the hook shank to take a hoisting line if necessary.
Pete Keillor
Reply to
Peter T. Keillor III
Thread the hook (shank) and bushings?
Capture the bushings between steel washers welded to the shank? You'd have to key them somehow to eliminate rotation.
I think I'd go the threading route (with a lock nut on the end of the pole). It might even come in handy to be able to remove the hook.
Reply to
Kyler Laird
You don't have to pin thru the center of the rod. Put the pin offset of center, so the pin interferes enough to retain without removing alot of material from the hook itself. Or alternately, go for the same effect as a 'weldon shank' end mill / end mill holder, using a setscrew on a flat.
Regards, Jim Brown
Reply to
Jim Brown
Why both ends? Seems that TIGing just the end that would hide in the Al tube would be plenty strong and avoid any weakness at the outside weld. Why do you weld both places?
Reply to
Ted Edwards
Ted, Just 'cuz I don't want to do it again. It is cheap and fast. Why not. Steve
Reply to
Steve Lusardi
Because it's almost guaranteed to be weaker with two welds. I would drill the SS bushing and counter sink the hole (inside end). I would then fill the V-groove (TIG) with 312 stainless (>100Ksi tensile). No HAZ and no chance of undercut just where the stress is greatest.
Reply to
Ted Edwards

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