Do you guys know a good approach to go from "acquaintances" to "friends" as adults?

I've been going to a club for five years. I know a lot of people there, talk with them often, volunteer and help out to keep the club running. It's a lot of fun.

But it feels like everyone is keeping themselves at arm's length, and we all treat each other as "acquaintances". We meet up, focus on the club, make small talk, and leave. I'm lucky if someone talks about a movie or video game they've played, or engages for long when someone else bringing it up. I've known some of these people for years, and I still don't feel confident I'm close enough to any of them to invite them to hang out outside of the club or group activities. For reference, they're all older nerd types, some with and some without families.

From your experience, what's the best way to make the step? Just force it, cold-call someone out of the blue and ask if they're up to do anything outside of the club context? Organize my own events and if anyone's interested, they can join?

>>33323477 (OP)
After your club activity, say you're gonna get coffee/drinks/eat and extend the invitation to everyone. See who sticks and joins. Invite them again. Repeat