Need help with a table saw.?

I bought an older portable table saw but did not get the wrenches to remove the blade. Using a screwdriver to lock the blade, I cannot seem to be able to remove the arbor nut. I have confirmed it is not left handed thread, as I can see the last few threads of the arbor. I want to try getting proper fitting wrenches to try again, but I am not able to get the size of the collar on the inside. The arbor nut seems to be 15/16". Does anyone know of a way to get the nut off, or, tell me the size if the collar wrench? It is a Black & Decker BDTS100, 10". Thanks