you can make your own insert out of plywood, about same thickness as you old one. Cut and fit, shim to get level if needed, and install. Slide the fence over the side, start the saw and crank the blade up, giving you a zero clearance slot. Go a little higher, and then drop the blade to where needed. Have had several of different slot sizes for years, and they work great. USE A PUSH STICK!!! Make some (a lot) out of 1/8 or 1/4 masonite or plywood, they are a consumable. Keep your fingers away from the blade!!
The metal one for the two saws I have are somewhere?! Like said above I make them out of 3/4” particular board with the laminate on one side, easy for material to slide on. I have maybe 5 for different cut sizes up to the 3/4 dado. That piece on the end is for the ‘divider’ that goes right behind the blade so board won’t ride up on blade and flip back at you (you can’t catch it, to fast). Anything less than 1-1/4 cut I use a push stick thingy, 1” x 1” stick with a big sharp nail out the end 2” the piece won’t pop up then. 55 years in the trade. Also buy the correct blade for material you’re cutting, a dull blade will hurt ya.
I’ve also seen many ‘Joe Bumbundry’ projects in my time but as long as you’re satisfied when done... btw the doors are where the money-jewelry is at.
