Martin Penning
fine stringed instrument maker

I custom fit ebony to the scroll and use side mounted levers, reducing the width of the extension. 

I make the levers from acetal and use black powder coated aluminium brackets. The "brake shoe" is made from neoprene, high density rubber for a firm buzz free fit.

Using a double wheel/pulley I can eliminate the need to drill into the scroll.

The string runs along a channel on the underside of the extension and over the second wheel, the string tension holds the extension in place.