Counter shaft Key

:oops: I am changing my standard 4sp to a OD. I have both trany but the OD one has a bad shifter mount. SO... I decided to just change the tailshafts. Long story short in order to remove the OD tail shaft you have to remove the counter shaft to alow enough room to get the mainshaft out. I didn't realize there was a half moon key in there and sheered it in half. can I buy that "key" from somewhere like brewers or do I need to try and make one?