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:
http://www.keithmcmillen.com/kbow/
the picture at the bottom of the page shows it best, this is a violin bow.

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....


Jon