I thought I would get some input on building a blade grinder. I understand how they work and I am sure I can build one. I do have a few questions. What is the part called that "rolls" the edge over? It looks like a rod with a spring around it with a handle on top with a roller on the end. Where would I get this? My other question is do you roll the blade mechanically or by hand like with a crank or is it under power. The 2 grinder wheels will be spinning by a motor then I wonder if the blade has to be going a certain rpm?? Maybe Aubry could weigh in on this or someone who grinds there own blades. I really appreciate it. One last thing does the roller come at the sharpened edge from the side then push the edge over or does it come straight on and force it over that way.