Though a little off topic, here is a challenging project for you wood turners. We have been working on this all week and after much head scratching I thought you might like to see our solution.

The picture shows an 85 ft carbon fiber mast we built for a customer. Normally the bearing that supports these masts fits inside the mast or is epoxied on to the mast so the outside dimensions don't have to have high tolerances. However the spec for the foot of this mast has to be within 1/1000 of an inch because it is designed come out to be lowered under bridges. You can imagine that after 30-40 layers of CF braiding the outside is not a perfect circle.

To get the supports ground to spec we built an 85 ft lathe and hooked up a router to mill the mast as it spins. Over the 85ft span the mast barely sags an 1/8th of an inch but is not exactly straight. Building a frame that would hold the mast and getting it centered on the chuck so that the whole thing could spin correctly was a bitch. Tomorrow we will grind the three rings of fiberglass wrapped around the CF that will be the bearing surfaces.

Hope you don't mind this off topic stuff but I thought you guys mightlike to see this.

Regards,

Jack