BW April 2018

4/2: I sanded several thick fibers in bundle 405 to get them through the chimneys more easily. Andrew put the fibers back in the collar and aligned them before I left, but we still wanted to improve the alignment. I recorded the new configuration and tried to improve the alignment, but a Kapton strip broke and after I replaced it I did not get a very good alignment.

I also practiced fusing today.

4/4: This week I started polishing a fourth bundle of sci-fis. I am still twisting right in front and left in back. The wheel is running in reverse.

Yesterday during fusing practice the hook on one of the 500 g weights broke, and today Jim suggested wire as a replacement.

I worked on preparing light guide bundle 403 for testing today.

4/5: After several attempts by Andrew and me, I put bundle 403 in the dark box with a satisfactory alignment. I started running tests.

I changed the 400 grit sandpaper, and polishing went much faster. Bundle 4 is now less than 0.005" from the target length of 0.787". However, it is hard for me to tell where we bottom out - i.e., which is the smallest feeler gauge that prevents the bundle from touching the sandpaper. There seems to be a gradation of contact between the fibers and the grit, with a thick feeler gauge such as 0.025" allowing slight brushing contact while 0.015" allows the paper to scrape vigorously against the fibers.