Those platform gitzo heads with 2 tripod screws, what size front?

[Drew Wiley]

You double nut the thing below, a standard nut plus wing nut. Gitzo had a nice wide thin nylon knob (brass inner thread) in lieu of a wingnut. If the official Gitzo thingy was hard to screw through, maybe some corrosion is present. Try cleaning the thread with a 3/8-16 tap first. If you need a big wrench, something is not right - perhaps even a flaw the bolt thread itself.

[ericantonio]

You double nut the thing below, a standard nut plus wing nut. Gitzo had a nice wide thin nylon knob (brass inner thread) in lieu of a wingnut. If the official Gitzo thingy was hard to screw through, maybe some corrosion is present. Try cleaning the thread with a 3/8-16 tap first. If you need a big wrench, something is not right - perhaps even a flaw the bolt thread itself.

I didn't need a big wrench. I just held it down with a red garage work towel to get a good grip and used the enormous power of my right thumb and pointy finger. And I yelled at it to will it to my doing. Yah, probably just corrosion. I've taken that tripod in a lot of weird places but never used the 3/8 until now. I now have something to attach it to! I'll remove it again, and run a good steel brush on it and dab the lower threaded part with some oil. Not the top part that will screw into a camera base.