Chachi
Just in case you are unable to find the correct part, contact your local Electric parts store. We have one in Grants Pass, OR by the name of Grovers, they carry nearly everything electrical. Lowes or Home Depot might help too. You might be able to get by with a variable switch meant for fans or lights. It probably wouldn't fit your saw but you could mount it anywhere and run the wires to the saw.
Gabby