I'd like to see a diagram of your apparatus.

What did you actually measure? How did you compute friction from what you actually measured?

How did you control the line speed (I would think that friction is fairly dependent on line speed)?

I've been trying to think of how one could set up such an apparatus using a scale as the measurement device. I can imagine one way to do it, but it doesn't seem very reliable to me.

Please don't take this the wrong way. I realize this isn't a formal, published paper.