I have wanted a pattern sander for awhile. One of my spindle sanders I have is an oscillating WEN with the nice heavy cast metal top. It has proven to be square to the top.
Took it apart today to see if I could make it stationary. Was very easy to do. Has 2 belts, one for the spindle and one for the oscillating plate. Removed the oscillating belt and I now have a stationary spindle sander.
Going ro be very easy to make a pattern sander! 2 flanged .5 inch diameter bearings and a delrin disc bored to except them, place under the spindle rubber pad. Trim pad to allow for the thickness of the pattern disc that will be on the bearings and you have a drop in pattern sander!