Topic: the Slik tripod improvement project.
A few weeks ago, I found this old Slik Master tripod on Craigslist--right here in town--for 25 bucks. I THOUGHT it was pretty heavy duty, until today. I had decided to remove the factory head, which is integral, and see if I could modify it to use my Bogen ballhead instead, and maybe in the process, keep the factory head to be used also.
When I removed the head, I about dropped. The "key piece" which holds the ENTIRE LOAD of the lens/camera is the pictured round piece, either cast aluminum or 'pot metal', which has a short brass piece cast within. This is a 1/4" US thread, and is only about 3/8-7/16" long so it's not very substantial. I could just picture my new 100-400L and the Canon Xt toppling to the ground if that failed!!!
I made the second piece on the lathe out of a starter solenoid plunger out of an old GM starter, and "hand ground" the flats to fit inside the center tube. Drilled the center for 3/8 thread, and will have to cross-drill it to pin to the tube, later.
It will be easy to adapt the old head if I want, just drill the original post for a 3/8 bolt, only THIS TIME I'll go clear through the damn thing.
The original tripod, head, and new plug for the ballhead
The new tube plug, drilled and tapped for 3/8
and the old head mount, showing the ridiculously poor brass nut arraingement cast into the swivel