Custom Screw-It Interchangeable Bit Driver, Copper/Brass-Celtic Brian Fellhoelter Custom Knives Here it is, the driver Brian uses to assemble all of the products at the Fellhoelter shop. Along with Steven Kelly of SK Knives, he set out to make a driver that was comfortable, dealt with the flaws they two perceived in other custom drivers, is fun, and spins for a long time if you are one of those twitchy, fidgeting types. One of the biggest complaints with the crop of custom drivers that Steven and Brian have come across is visibility. They all use the short driver bits and are generally larger in diameter (the Screw-It is 0.375" in diameter or about 9.5 mm). The short bits cause at least 2 problems for Brian; they block the visibility of small screws which makes them awkward to use and they don’t reach into tight places. A common place that gets him is the low ride pocket clips. Many of the bits do not reach in them. And if they do, they block the whole hole, so you can’t see what you're doing at all. They fixed that by using 2" long power driver bits. They cost more, but Brian loves them and thinks you will too. He even provides you with T6, 8, 10, and 15 Torx bits from Wiha which are the most common sizes used on knives. More bits can be bought at any hardware store, and less common bits like the Torx are found at industrial supply houses like McMaster-Carr and MSC. The ball uses a hybrid ceramic bearing. You can remove the ball for cleaning, but not the bearing from the ball. You can also blow air or brake cleaner in the hole in the ball, which blows through the bearing and keeps it spinning at max speed. The bits are held in place by a magnet, so they are very easy to change from one size to the next. If you are lazy like Brian though, you’ll just want several drivers, in different materials, for each size. Then, you can tell at a glance what is what, and never slow down.