Besides all the good info above, you also need to look at the end speed of the motor, and everything down the line. You are talking about doubling the speed, so you will be doubling the centrifugal forces. Are the winding's going to stay in place? Since you are starting with a 1735 RPM motor, you will likely be ok at 3450. If you started with a 3450, then I would have some concern. Now look down the line, what are you driving? A spindle that runs at 2250, with the 1735 RPM motor, will be looking at 4500 RPM. will the spindle and bearings hold up? Since you do not mention, I can only give an example, and hope that you and others contemplating the same move understand, and take a look. When things turn faster then they were designed and can withstand, the results can be deadly. Looking at the whole picture, and applying common sense goes a long way.