Should I give Dad back his gun?

Absolutely NOT. I’m lifelong Alaskan, feel strongly about gun rights, but once behavior deteriorates, to the level of what you wrote, those rights are over. I’ve been surrounded by violence against women, my entire life, living in a state that has one of the highest rates of that type violence, so I do not play around. I would NOT take threats lightly, jmho.

Seriously? Your question is "should I give dad back his gun?"

Is it just me?

So, you have your dad, whom you say you don't trust. living with you, armed, and he threatened your WIFE with a DEADLY WEAPON, which he "always has on him" and your question is "should I give dad back his gun?"

Your question should really be "what is the fastest way I can get out
of this house, because dad is a danger to me and my spouse?"

But since your question is "should I give dad back his gun?" - ah, no. You should not give dad back his gun. I would think this would be kind of obvious. If what you're actually looking for is "permission" to NOT give dad's gun back from a bunch of anonymous strangers, I wholeheartedly give you permission and a blessing to get any and all firearms out of the house. And bear in mind, that a gun is not the ONLY dangerous item in the house.

Seriously? He threatened to kill your wife and you are asking if you should give him his gun back. Why is he still living with you?

no. He agreed not to use the table saw, but he did. Now he says he will never hurt your wife.
Not worth the risk.

Considering the circumstances, how can you even ask that question?

Unequivocably, hands down, NO.    The fact that he threatened your wife, carries a revolver everywhere, and isn't conforming to safe  (let alone your) standards, suggests to me that it's time to ensure he never gets another revolver, or other weapon, but also might be more suitably cared for where there's much more monitoring available to protect others.

You might want to discuss this with your local police, right now. 

Gun and power tools have to go! Or dad goes. Or you and your wife go. Figure something out because he is dangerous to himself and others. Sure, when he wants his gun back he says he won't hurt her, but what about next time there is an argument? He has no self control.

If I tell folks they can't smoke in my house, that doesn't mean they can do it when I'm not home. If the wife is allergic to the products of the power tools, the power tools may not be used in her home.

This sounds like an ill-conceived living arrangement from many points of view, and as I suggested originally, get yourselves to a lawyer and get dad an accurate assessment of his cognitive state.

Am I the only one who is thinking "Who the heck uses a saw and planer in the house" ? no ventilation, dust and mess everywhere, and oh yeah.. he agreed not to do this? My Dad and hubs both used/use these things and they would never have thought to bring that mess into the family home! Garage or shed yes... house NO WAY. Its a health hazard for anyone around the dust. I can;t imagine the clean up after that,, and I am SURE dad was not going to do it..
As to the gun,, when my dad threatened my mom,, the gun and ammo were GONE. They stayed gone. And I never felt a moments guilt

You have to ask? What is this, another ridiculous thread just to waste people's time? If you have to ask, then you shouldn't have it either.