These collets have no more than 1" threads on the end so unless you have a short drawbar or don't switch to fully threaded as an adjustable alternative you will damage the drawbar when tightening. The drawbars are luckily cheap and easy to replace, but if you try to tighten the chuck, the threads will snap before the cutter is properly tightened and jam until the cutter is seated and you're pulling the drawbar threads through the unthreaded portion of the collet, breaking. This doesn't happen with better collets because they have a 2" thread at the top. This brings me to my second problem. The threads are not cleaned at the factory. The first few threads were worn out like hell and wouldn't thread into anything. After I drilled the tap through, the burrs broke off and all was good and smooth. If you don't have a 7/16-20 tap ready, don't Expect this collet to fit you. Which in combination with the first problem leads to th oh this time the advertised hardening statement is actually true. These puppies have been factory hardened and are very durable. This means you can't thread further to fix a short thread problem, but it should be strong enough for years of use. slide into the feed. I would really like to give this collet a significantly higher rating, but cutting a thread shorter than usual and then not cleaning it properly is going to cause a lot of trouble for a lot of people. I have a modified set of 7/16-20 drawbar taps and dies and a thin whetstone so I could troubleshoot production issues, but that's something a buyer shouldn't do. Otherwise a good collet - good runout, good lasered size on the face, solid enough and even the face has a slightly flat surface so it gives back the last millimeter of play.