This is the best bit you can buy for CNC sign making hands down. I started with inexpensive bits and went through A LOT of them. I thought I was saving money but really spent so much more than I realized. I finally found Amana Tool and decided to try the carbide tipped V-Groove bit. Those were so much better than the cheep stuff I started with but would wear out quickly (for me since I run a wood sign business). Now with this, not only do I get a sharper and cleaner cut, it lasts way longer and I can replace the carbide inserts at a third the price of one of there other bits. Insert knives are made from solid carbide and much harder since it's not a brazened bit.If I could take 1/2 star away I would only because replacing the insert is not explained anywhere on the packaging nor on Amana Tool's website. I had to email and call and got a couple different answers before I got the right information from Frank over there. The trick is to start the screw, push the blade in towards the tool and up away from the tool as far as it will go, then tighten the screw. This gave me perfect results. The issue of getting it wrong was that it destroyed an insert knife by breaking off the tip when testing at the wrong placement. You have to get this right if you want it to cut the way it does fresh from the factory.One last tip for you. When you buy replacement knives. spend a bit more and buy the ones designed for MDF. I talked to one of Amana's technical guys and he explained that the carbide is a higher quality and will hold its edge longer. Sure, you might not need anything more than the general purpose (that's what comes on it), but it's nice to have the option and have something just a bit better.