These mandrels are nice.....just not very durable. The first one that came with the kit lasted about 75 holes. The replacement, not even that many. What happens is, the cheap sheet metal ring that holds the pilot bit detent ball fails. Detent stuck in limbo, pilot bit won't lock, and hole saw won't seat. As a licensed plumber that relies on his tools for productivity, I'm going back to the old fashioned arbors. The hole saws rock! Just wish I could use them without the quick change junk.

In response to my earlier review, the customer service was great! Diablo contacted me within a couple days after posting my review. That alone shows me that they take customer feedback, and satisfaction seriously. Yeah, the durability of the quick change mandrel is something to be desired. Having said that, the hole saws themselves are outstanding! I too had an issue with them when I first tried them. That's when I realized, these are not hole saws for slow pokes! They LOVE to be ran fast! Don't spin them slow. Run them as fast as your drill will go, and they will eat wood like nobody's business. Have you tried the reciprocal carbide blades for cast iron yet? Amazing! Nothing short of black magic! Would I recommend Diablo products to a friend? Absolutely! I would ... MoreIn response to my earlier review, the customer service was great! Diablo contacted me within a couple days after posting my review. That alone shows me that they take customer feedback, and satisfaction seriously. Yeah, the durability of the quick change mandrel is something to be desired. Having said that, the hole saws themselves are outstanding! I too had an issue with them when I first tried them. That's when I realized, these are not hole saws for slow pokes! They LOVE to be ran fast! Don't spin them slow. Run them as fast as your drill will go, and they will eat wood like nobody's business. Have you tried the reciprocal carbide blades for cast iron yet? Amazing! Nothing short of black magic! Would I recommend Diablo products to a friend? Absolutely! I would however warn them about the mandrel.

Perfect for the job