Most hole saws are for metal not wood anyway. Notice how they usually burn their way through a nice piece of lumber? Any local hardware store carries hole saws...Home Depot to mention one of the many stores. Use
oil or even wd40 works too. I would use what I got, don't go buy someting new. Hole saws are expendeble and can be replaced when all used up. Remember to protect your eyes especially if under the frame, also metal burrs are hot and
oil is messy. Good luck. John