I suspect it's not designed/intended as a photography stand. But from looking at it, I'd start by removing the brass top. It MAY be simply screwed in. If so, the remaining threaded hole may be able to have a piece of thead rod (or cut off long bolt) screwed in that has the standard mounting bolt size (I can't remember the dimension...getting old really stinks!). However, it looks like a spring loaded popout little ball that locks in the rod, so I'm thinking there's no threads.
The top knob in the picture appears to be a vertical adjustment 'clamping' mechanism. If so, the 'spring type' ball lock would make sense and there's multiple such locks on the rod. So, I'm guessing the bottom knob could be some kind of 'normal' ball head control. In which case, unscrewing the top black part MAY expose the right size thread...or one that can be adapted to the proper size.
If all else fails, unscrew or otherwise remove the 'ball head' part. There must be some kind of thread-on method to attach the 'head' part (or parts, or assembly) to the 'base' tripod. Hopefully, IT would be the correct thread size. Then it's simply a matter of purchasing your choice of ball or pan heads for the tripod and screwing them in.
One concern I have is that of weight capacity of the tripod. If it 'easily' flexes when you press down with gentle pressure, I'd be very leery of putting several thousand dollars worth of camera gear on top of it.
I'd agree with Tony; background stand or similar. I'm guessing you just need to drill out that little brass rivet below, pull that spigot out and fit in a standard one and secure with small screw or rivet.
There is no springloaded ball-bearing mechanism on the stud. It's just a smooth brass stud and it can't be screwed off. If you take a close look at the pic. There is dowel/detent holding the stud securely to the stand.
Your hypothesis makes sense...
Thanks for your input, guys...
I appreciate all the feedback.
I bought a demo profoto kit from ADORAMA and they sent me these stands. Which were worthless since the monolights couldnt be held by these things. So then they sent me a capable pair of flashpoint stands, and told me to keep these.
They're functional stands, except for that stupid stud. I'd like to use them to hold reflectors and flags but I don't know of any possible adapters that can turn these into practical stands.
Even easier, just turn a 3/8NC thread (or 1/4NC depending on size, but it looks large enough for 3/8) on the brass post and thread a regular spigot right on to it... Should take all of 30 seconds and cost exactly $00.00.
I don't think a speed light/umbrella adapter like a manfrotto 026 will clamp onto these. The spigot is to small for conventional monolights to clamp onto and those adapters clamp on to conventional spigots.
The spigots aren't threaded into the stand, they're punched in and secured with a dowel.