You might find cutting edges at a place that sells teeth and grader blades, etc. If not a good steel supplier could cut you one and bevel it for adaptors out of a harder more wear resistant material like AR400. They may recommend an even better material too. They should also know what filler metal to use for welding it and preheat requirements, etc. I'd guess at least 8018 and maybe even 11018 but what filler metal to use should be common knowledge for the steel supplier.