A couple folks asked me to update my progress on this topic. I was looking for octagonal aluminum stock to make tension adjusting knobs for carbon fiber bows for stringed instruments. Main reason for octagonal stock is that, apparently, the knobs have always been octagonal.
Well, we abandoned the idea of octagonal stock, instead I designed a finned knob. Finning was the easiest way to reduce weight, and it lends a high tech look to a high tech bow. The bow can be seen at:
I'm making the finned knobs in 4 sizes, and the black block (called a frog adapter, seen between the bow and the circuit board) in 3 sizes. This has been one of the neatest projects I've been involved with in a long time. Outside of the functional requirements, weight reduction was primary, with asthetics being important too. The final designs are based upon Keith's initial drawings, but was given carte blanch to reduce weight anywhere I thought we could get away with it. Weight is such an issue in the violin bows that the tension screws are titanium, which combined with the finned knob, saved about 1.5 grams. Last round of weight reduction on the violin adapter netted a .8 gram reduction, which was significant as a percentage of the overall weight.
The first pilot run is out for anodize and should be back Wednesday. I'll take some detailed pics of the frog adapters and knobs and post them to my website, with a link here to follow up.
Just thought a few folks might enjoy seeing what I was up to....