More information on the collimators

[Kirk]

A few people have asked, so here's some pictures showing details of the collimators. The main tube is aluminum and the small (bottom) tube is brass, which makes them thread together much more smoothly than if they were the same metal (aluminum on aluminum tends to bind). The main tube has a groove cut around it near the top that the set screws on the top mirror mount ride in. This allows the ring to be rotated but still be held captive - very useful if you mount them upside down, which we have. Both lenses are held in with threaded rings and can be easily removed. The lenses currently installed are BB AR coated plano lenses from Edmund Scientific (you will not see chromatic adoration in beams). They are -25 mm and +100 mm. The top mirror mount has an MM-1 style gimbal on it that is mounted to a center of rotation offset plate so that the mirror rotates about the reflective surface, so there is no offset as it is rotated. It rotates on a pin that goes through a clamp on the arm. The clamp can be tightened or loosened without rotating the gimbal. The pin also extends past the clamp and has a small hole through it. The clamp screw takes a 3/32 allen driver and the hole is sized for a 5/64 allen driver to fit through. The idea is that you use the 5/64 driver as a lever to position it and the 3/32 driver to tighten it. These were originally designed for a fiber fed beam table. The goal was to use a short lens on the fiber collimator so the beam on the table would be tight enough to be picked off by small mirrors on a GM20 (small=fast). The GM20 shot the beam up through the 4X collimator and to the top mirror for final positioning. The whole system worked great, but we are out of the Laser biz now, so I'm hoping they will find a good home.

I would like to get $50 each for them (the lenses alone are worth that)