Hot Water Straightening Light Guides Procedure

The fibers come bent from being wound around spools. For the tagger microscope they need to be straightened before being bent again in two places. Straightening the fibers involves mounting them on a straightening bar and heating them in water.

Before mounting the fibers on the straightening bar, remove excess rust from the bar and apply spray paint if necessary. If you paint the bar, wait for the paint to dry before mounting the fibers. In addition, slide the collars back and forth in their slots until they are free to move in case there is rust holding them up.

To mount the fibers on the straightening bar, use the bundling tool shown in figure 3 to arrange them into a 5x6 matrix. Keeping the fibers in the bundling tool, bring them to the Unistrut bar. Rotate the bundle so that six fibers will rest on the bottom of each collar (closest to the bar). Screw the fixed anchoring collar at the end around the bundle, but not so tightly that the fibers cannot slide. Press the ends of the fibers one by one against a flat surface so that they line up. We will call this the aligned end of the fiber bundle (see figures 1 and 2). Tighten the anchoring collar around the fibers so that they cannot move anymore. Fit the other collars around the fibers, making sure that at each collar they are still arranged in a 5x6 matrix. Slide each collar toward the aligned end of the bundle and tighten it.

The collars need to be toward the aligned end because the fibers expand as they are heated. As they stretch out, the collars should move away from the aligned end so the fibers will not curve and become wavy rather than straight. To make sure the fibers will be straight, there should be a force pulling them away from the anchoring collar. This force is applied using springs attached to the straightening bar. All but one of the collars should have a spring or two attached to it.

The springs are tied to the collars with sections of electrical wire. Where there is one spring for a collar, the wire is passed through the holes in the collar that are closest to the bar (figure 5). The collar at the unaligned end of the bundle connects to two springs, with tying wires going through holes on either side of the collar as pictured in figures 6 and 7.