Review on Norseman Premium 44170 240 UB Degree by Phillip Johnson

There seems to be a mix of reviews so this review is for the Jobber 44170 Length Twist Drill Bit Set. In short, these are excellent twist drills for general metalworking applications. To elaborate, Norseman says it's a NAS 907B. This is an aerospace industry standard and specifies that twist drills should have a 135 degree split point, be made of M2 or M7 HSS and have a slightly thicker web. slightly better than the more common 118 degree twist drills. It's a small difference, but it can really make a difference if you're drilling a lot of holes. For larger sizes I still drill a pilot hole to ensure the point has play. High speed steel comes in many types. If you look in Machinery's Handbook you can read about M2 and M7 HSS. In fact, M2 is the most common for tools like twist drills. According to Norseman, these drills are high molybdenum and NAS 907B compliant, which probably means they are M7. The Machinery's Handbook seems to say that the M2 and M7 are actually almost interchangeable. M7 can be tempered a bit more. The jobber length is an all-purpose length. Short drills are shorter (and therefore stiffer, making it easier to place holes more accurately). The plane is longer. Jobber is spot on for general use. These drills appear to have a black oxide coating on the flutes, but the rest of the drill is uncoated. Black oxide retains cutting fluid well when drilling steels. Black oxide is instantly erased when drilling aluminum. If you look at the first picture you can see where the black oxide is rubbed off. The second picture on the left is a Norseman twist drill and on the right a Chicago Latrobe Black Oxide drill (another excellent drill). The Chicago Latrobe drill was used very often on aluminum and removed the black oxide very clearly. Norseman leaves most of the bit uncoated which means it will stick better when used on aluminum while still working well on steel. The 135 degree angle, jobber length and finish really make these twist drills the ideal general purpose twist drill bits for metalworking in my opinion.