Gone Fishin'

The basic principal of bracing is to preserve the relationship of the headstock to the swingarm pivot that isn't being done with the current set up. BMW's frame was designed to mimic the famous Norton "featherbed" but it's a design that's not up to the task that modern rubber can provide. We've decided to add a brace from the swingarm across to just below the headstock. That long of a brace could flex if unsupported and certainly wouldn't be strong enough if simply bolted on so we're welding the brace across the span and triangulating it into the spine tube.

So fitting all those angled tubes can be a complex task. The technique is called fishmouthing and involves matching the intersecting angles and cutting the tube with a hole saw of the size of the mating tube. Here Scott is cutting one of the short triangulated spine tubes on the Bridgeport mill. The Bridgeport could be thought of as the worlds biggest most versatile drill press - of course a real machinist would cringe at that description.