John K Jordan
I'm almost 68. For now I don't have problems with weak hands but I do get cramps and soreness, mostly after gripping small things too long. The worst for me is sanding at the lathe since I sand mostly by hand with the lathe off.
But first, have you seen to a doctor about this? Seems it would be important to see if they can find any specific problem before starting on a self-treatment program. About 20 years ago I had horrible hand problems with pain and dexterity and some numbness. The doctor checked for arthritis and other things but it turned out to be a problem with nerves from an elbow issue, confirmed by a neurologist. A physical therapist showed me some things to help. One was increasing the size of handles with foam sleeves. Also recommended were finger, hand and wrist exercises. And the rubber ball - I used to carry one and use it many times a day. They had special balls the right size and with just the right amount of resistance.
Those problems are long gone but I deal now with the cramping and soreness. What helps me the most is stretching with breaks. I stretch all fingers outwards and hold, repeat. I stretch and flex each finger one at a time. Press all fingers together with both hands. Massage each hand with the opposing thumb.
Another thing which might be worth a try for sore hands. I used to "warm" up for piano playing by soak both hands in a sink of hot water for a few minutes. This worked wonders! (especially in the winter) I haven't tried it in the shop since I don't have hot water but remembering it just now I think I'll walk up to the house and try this the next time my hands cramp.