I decided to make an alteration. Without any thought I marked 4 locations each for 2 sets of clamping t-nut holes. Upon some thought occurring I decided on one of those 4 locations. That location is very close to 510/520 table holes for a "real" shape/rout/sand fence.
So counter bored two holes with 7/8" bottom and 3/8" top diameter. 3/8 for a t-nut sleeve and 7/8 for the t-nut flange od. Used a "horizontal drill press". Awkward fer sure but I had already aligned the 'legs'. Not impressed with table raw material - resembled impregnated paste board(think cereal boxes).
Holes done. Now What to use in those t-nuts. 5/16-18 low profile cap screw that has a 5/32 hex socket.
The deed is done! Screw length results in about 2 turns needed to tighten once threads are engaged. I intend to make washers with a tighter fit to the screws. The fence is the current version.
Now about mounting a router . . .
