This mount will fit a pegboard with 1" (25.4mm) spacing, and was specifically designed for Dremel Lite Model 7760 - however, it may fit other rotary tools with similar dimensions (23-24mm diameter).
 

This mount will take up 1 Row x 2 Columns on a pegboard. Because of this, it was designed to have a snug fit in order to minimize vertical movement. Don't be afraid to apply some force to get it to snap into place! If your pegboard has a different thickness or hole diameter, please let me know and I can do my best to help dial in the tolerances to fit your needs.

As always, feedback and comments are very welcome as I am new to this and learning every day.