When using my model 103 cutter, I've found that if my hands are wet or if I have flux on them, it's really hard to turn the wheel because the grips aren't too good on it. To solve this problem, I used a hacksaw and made slightly deeper grooves in the knob. I made shallow cuts every 4th groove, and it has greatly improved my grip when my hands are wet or dry. A lot of times it's tempting to use a pair of pliers on these cutters, but after time the pliers wear the knob down so much that it's impossible to turn the knob by hand. If deeper grooves were included in the design of the tool, it would improve it greatly.