I gathered some ideas from youtube and decided to build my own router table with insert since I'm using a cheap router and this would make height and blade changes easier.
Total necessary parts for this project: a router (already had) - Metal table for saw (already had this but this same idea could be built out of some wood scraps) - Some sort of saw to cut the table, insert, and bit holes - Drill, bits, and countersink - Machine screw assortment < $4 @ KMart.
Here is the table I had but any table you are able to cut an insert plate hole into would work or just use some scrap wood.
I created a table surface from some $2.85 clearance shelving from Home Depot, cut an insert rectangle out and then used strips of wood glued and screwed to the underside to support the insert with the router
Notice I created the insert out of a different piece so it would fit tighter. I removed the router base plate (not shown) and traced out mounting holes and simply traced the cutout I made in the insert surface.
I drilled and countersunk the mounting holes and you will notice there are more holes than I used since the original holes had a different thread than the bolts I had on hand and I didn't realize they wouldn't fit properly until after...Duh.
The only issue I had with this new plan was I had to trim the washers I used to fit around the router.
Top view of cutout with mounting flanges and then with insert attached.
Note the bit hole is a little funky as my jig saw blade mount broke while I was cutting and I had to use a junky on to finish, not that the good one was that good...LOL
View from bottom of table.
Its been a while since I made on of these...hope its clear enough.
Let me know if you have any questions.