At 8:17 AM +0000 11/20/09, kevin sayles wrote:
>GB stems where often drilled for the front brake cable, and may have
>had a neat adjuster.... or maybe I'm thinking of something else?
>
>As Eric says...should be checked for cracks, specially as having a
>hole go right through your handlebar stem does sound quite 'scary'
It all depends. The hole to pass the brake cable is very small, so you are removing hardly any material. A round hole doesn't introduce stress risers, either.
The biggest problem is drilling the hole so it lines up with the stem quill and the brake, so the cable run will be straight and parallel to the head tube.
The enlarged hole for the housing stop doesn't have to be deep. When I drilled a stem for a Jack Taylor (impossible to find a hanger to fit the OS headset back then), I made the larger hole only 3-5 mm deep. I did not use an adjuster, as that would have required a larger diameter and deeper enlargement for the housing.
You probably want the bottom of the enlargement for the housing to be smooth. If you have an old drill bit, you may well put a few stress risers in there. Using a new bit with lots of cutting oil can make you a very smooth enlargement of the hole.
I have seen many a Jack Taylor tandem with drilled stems, often with the larger adjusters. Does anybody know of failures?
Jan Heine
Editor
Bicycle Quarterly
2116 Western Ave.
Seattle WA 98121
http://www.vintagebicyclepress.com