Changes

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.

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 vigorous scraping of the paper against the fibers.

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.