So long as we have a Dynohub™️ thread, let's talk about...threads!
The GH6 (front hub!) Dynohub axle is a 3/8x26tpi. The threads on the terminals are 2BA, a British spark plug thread size.
Now, you're probably asking yourself, 'Self, why is his axle so long?' Well, I'll tell you. Some of the GH6 Dynohubs were built for the old roadster bike front OLD of 90mm. Yeah, that's not long enough to fit in a standard 100mm OLD fork. So I replaced the axle in this NOS Dynohub with a generic one - but, and it's a big but, on a Dynohub axle, one of the cones screws down against a stop. On the generic replacement axle I simulated this with some blue Locktite.