The problem:

I love Kahler bridges, and equipped the first guitar I ever built with one.  I also like real heavy gauge strings, and use them on it too.  One day in 2010 while tuning the low E string, the fine tuner lever/string holder snapped.

The remedy:

I didn't even look for replacements, because I worked in a place where I was the one who did all of the engineering and machining of mechanical parts, so I just decided to make new ones, and improved ones at that.

As with all of this kind of work, it is good to have a drawing with specifications, so I made one:

The original ones were cast out of some alloy I could not possibly identify, but I did know that cold rolled steel would do the trick.  I also saw that there was enough free space in the bridge to make the new ones bigger where it counts for better structural integrity.

Making the parts:

I did not take any pictures of all of this, but in essence I started with a rectangular piece of steel, drilled a hole through its length for the ball ends of the strings, and one for the pivoting pin that holds them into the bridge.  I shaped it in one piece on a milling machine to the new dimensions, leaving extra material where needed, but had to file the radii by hand.  Then I cut it into six individual levers, cut individual string groves into each one, to accommodate the string gauges, shaped the round ends where the tuning screws push down on them, and smoothed them out.  Finally I lacquered them black, and installed them.

Here is an altered version of the drawing to show (in red) where I left extra material for strength:

Here is a picture of the new ones in the guitar (dust and all), I don't want to go through the labor of taking them out just to take a picture, but may add one here at a later time:

The verdict:

The new fine tuner levers have performed without a hitch so far, and show no signs of giving up anytime soon.  Since I get to talk to Gary Kahler and his son every once in a while, I did bring it up in conversation once, and Gary told me that they have improved the design, and now also offer levers for heavier strings.