There have been lots of threads concerning what tool is best to use for the removal/replacement of a Copeland sightglass. I thought I would add a pic of the one I made a while back using a standard 3/4" six point socket and a couple of pieces of copper tubing:
The removable copper inserts are to center the tool in the sightglass. I found that you need two sizes, depending on what type of sightglass you're working on. The current, one-piece style uses slightly larger 3/4"OD x 3/4"L piece and for the older ones I used a 5/8" coupling cut down to about 3/4" long. The socket was cut with a hack saw by hand, so while it's not the ing greatest machining job, it works quite well.
BTW, this works for E, K, L and 3A Copeland compressors.
(Yes, I need more practice getting my camera to focus on closeups...)