Finally received the bored-out steel ball from the machine shop. Proceeded to install this on the end of a piece of rattan. Fairly self-explanatory pictures follow.
The thing with the helical fins is a threaded insert, made for driving into soft materials such as wood, plastic, and rattan. The general idea is that after the rattan has been pilot-holed and shoved into the large bore in the steel ball, this insert is screwed into the pilot hole from the top using a large Allen wrench. As it goes in, it expands the rattan against the inner surface of the bore, creating an extremely tight fit. Finally a large flat-headed bolt is screwed into the inner thread of the insert, capping the ball and holding it in place.
Part of this went to plan and part of it didn’t.
First of all, the ball is rather large–1.875″. Originally I had supplied the machine shop with a 1.25″ ball of stainless steel, but it turned out that I had inadvertently purchased one that was made of an exceptionally hard alloy that was too difficult to cut. They sourced the larger ball, which is made of mild steel, polished to a shine that makes it look like stainless. They were unable to obtain one of smaller diameter.
The first part of the installation went well. The rattan fit snugly in the bore (I had to pound it in with a hammer) and became even more tightly wedged in place when the insert was screwed in. The only problem was that my pilot hole was slightly off center to begin with and the insert went in somewhat crooked, with the result that when I screwed in the flat-headed bolt, it did not go in straight, and ended up perched at an awkward and unsightly angle above the top of the ball.
So far, not so bad for a first attempt. The main problem with the result is that the ball is far too heavy. I have created what amounts to a stylish sledgehammer. It feels unwieldy even in two-handed maneuvers.
Interestingly, the ball looks to be of a nice, proportionate size and feels perfect in the hand. So the experiment succeeds on an aesthetic level. If made smaller it would look odd and feel wrong. But there is no doubt that it’s too heavy, which makes me wonder how Vigny did it. I am wondering if he used a hollowed-out ball.