I have an old Delta Rockwell 10" Contractor table saw. I bought it new almost fifty years ago. The throat plate has become a little sway backed. How interchangeable are throat plates? I don't have the Model and Serial numbers with me at the moment. What about leveling the top of mine with some body putty or epoxy? Where can I get a new on that will fit?
I have made some out of plywood but you have to be careful with those when you go to tilt the blade.
I also have a number of inserts for my throat plate and I prefer to make new ones so that I have a zero clearance on the blade no matter what angle I am cutting.
I have bought several of these over the years to make plates out of. They stay slick and flat. Find some in the size you need. If not exact size go oversized a bit and cut to fit. I shim with tape or playing cards.
I usually make mine from 3/8" Baltic Birch ply, as do others here. I usually make a batch from one template, install a dado stack in the saw and remove most of the birch under the future slot. You will find that most 10" table saw blades on most saws will not retract the full thickness of a 3/8" plate. I also like drill a 1" finger hole in each plate blank and chamfer their edges.
I use four each, #4 flat head wood screws for leveling, installed from the bottom of the plate, either Phillips or flat blade. If you make them from phenolic or other plastic, they might last longer, but they also dull the blades and bits used to shape the insert and cut the slot and the dado stack. I like to write the angle of the slot on the top and bottom of each plate in large black letters the first time I cut the slot. Make sure the angle is written so that it is right side up when you hang the plate from the extraction hole.
If you want to be really picky, stack them in order by angle on the peg. Some organization is even more important for your dado stack zero clearance inserts, since stack width, bevel angle and depth of cut can all be important for these plates. plates