The Vevor 13B is one of those rare off-shore products that really works, and works well. Right out of the box I was able to take a cheap drill bit I had on hand, sharpen it and put on a split point (technically thinned the webbing). The sharpened bit easily drilled through some 3/16” plate steel with little effort. The Vevor is sturdy and well made, and the collet has close tolerances so it fits snugly in the sizing and grinding openings. I took off a star for the almost complete lack of included instructions and the horrible (nonexistent) support on the Vevor website. I asked a fairly simple question, and after 4 days of AI-generated blather I turned to Youtube where I found several excellent videos describing the differences between the 13A and 13B, as well as tutorials on how to use the machine. The Vevor works so well that it actually takes longer to watch the videos than to sharpen the bits yourself. But watch the videos, they make using the Vevor a snap. Overall the Vevor 13B is excellent addition to my shop. I hate dulling a bit on a weekend night and having to spend 30’ driving to buy a new bit, or waiting until the next day if the stores are closed. This takes 2’ and I’ve got a new bit ready to go. The obvious comparison is the Drill Doctor. I have a Drill Doctor, but it is a toy compared to the 13B, and costs almost as much. No comparison, the Vevor consistently produces an excellent finish and a fast cutting bit. The Drill Doctor takes longer and is not as reliable; in my hands about half the time I have to take a 3rd or 4th pass with the DR, and sometimes even that does not make a useful bit. With the reliabilty of the 13B bit, the DR will go on marketplace or the scrap heap.