Measuring in the pump
Dear pumpers I just wanted to share something which I have been doing since I started pumping and just realized may be useful for the rest of us who use clear cylinders. It is my method of measurement in the tube. Alot of tubes come with measurements on the tube, and anyone who has had one of those probably found it to be slightly inaccurate, so you make a few marks with a sharpie right, and measure with that. Even with marks like that my measurement would vary by about a half inch depending on the angle I was looking at the tube from. What I ended up doing is marking around the entire cylinder to the nearest quarter inch of my fullest pump size which is now 6.75. By making one continuous straight line around the cylinder I could line up the frontmost and backmost lines to be sure I was looking at the cylinder at the same angle everytime, and now am able to determine the smallest differences in length expansion.
I hope this made sense and is useful to you guys.