Good morning, Steve Smith;
Thank you for the additional information regarding the fastener system devised by Sir Joseph Whitworth. My copy of MACHINERY'S HANDBOOK was a casualty of the death of a marriage (along with the rest of my library), and I admit that I was going by memory alone in trying to recall his name. When working on English motorbikes, his full name was rarely, if ever, given in the repair manuals. With the links you provided, I can at least retrieve the specifications for the fasteners for storage on the computer.
And, I see that at least one other person is curious why Bella wants to mount a digital camera atop a Minolta X-700.