Originally Posted by rogerstg

There was a thread a little while back about a DIY tool. It seemed like it would do the trick. FWIW, despite what others have written, the RD does not need to be very accurately aligned. In fact, the only time I've had shifting issues due to hanger alignment, it was way off, like a 1.5"+ difference on the alignment beam. I checked all my other bikes, which shifted perfectly, and they were all off a noticeable amount with no ill effects.