Four Spiral Flute M35 Cobalt Step Drill Bit Set 1/4" - 3/4"(9 Sizes),Impact Ready Four Flute Step Drill Bit,1/4" Hex Shank Step Bits for Metal, St...

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The media could not be loaded. Really worked much better than I thought it would. As the video shows it had no problem cutting through this brake drum.

Its hard to beat a well made step drill. This one is a bit next level. Its easy to use one improperly aka drill larger than your needs? Im not the step drill professor, but I had to learn to pay a bit more attention to the depth than a standard drill? This should be obvious but for my degree of vision, Ive painted a bright orange mark as a depth marker (in addition to a target circle) which sometimes helps? The essential value of a step drill for me is the durability of the cutting edge over time. Of course that depends on what material you use it on? The cutting design is critical but ask a machinist why? This one is made from the right (cobalt HHS) materials, and TiAIN finish. Simply this drill works great on stainless which is a substantial material. That it looks like you could drill to the Center of the Earth is just impressive. Please ask a machinist as they will go into a professional tutorial about step drills:) I'll report back with an extended user update.

This stepped drill bit is very well-made, well-finished, and has a good range of hole sizes. The steel is great for metal drilling, and everything else I've throw at it so far. As another reviewer mentioned, the only real down-side to this bit is the lack of labeling. Having legible markings at each step saves a lot of time, since you don't have to keep stopping to check the hole size.

Review: PANOVOS Four Spiral Flute M35 Cobalt Step Drill Bit Set 1/4" - 3/4"(9 Sizes), Impact Ready, Four Flute Step Drill Bit,1/4" Hex Shank, Step Bits for Metal, Stainless Steel, Aluminum, Wood, Plastic Sorry for the following definition of M35 Cobalt coating, which is on this step drill, but it's good to understand the hardness level of this bit. M35 has a very high hardness for this step drill, with the addition to a 5% coating of Colbalt. There are actually two different types of this coating. The difference between M35 and M42 is the amount of Cobalt. M35 has a 5% Colbalt coating and M42 has an 8% Colbalt coating. The M35 steel, with the 5% Colbalt coating, is referred to as TiAlN, which means Titanium Aluminum Nitride while the M42 is referred to as Aluminum Titanium Nitride (AlTiN). The hardness of M35 drill bit is usually between 65-67, and the hardness of M42 drill bits is usually between 67-70. The M35 (this step drill) is less hard than M42, but M42 is more brittle and more susceptible to breakage at high temps. The Titanium Aluminum Nitride (M35) advantage over M42 is its retention of hardness at higher temperatures due to the oxidation-resistance and, although 8% cobalt drill bits will drill slightly harder metals than M35, they are also more brittle and therefore more likely to break if not used in a very controlled situation. The hardness of M35 drill bit is usually between 65-67, and the hardness of M42 drill bit is usually 67-70. The price of M35 material is also lower than that of M42. Now onto this step drill bit. This bit does have the M35 coating and will drill hard metals. It is very sharp to the touch and could have easily cut my fingers if not careful. I've attached some photos trying to illustrate this. It has 9 steps from 1/4-inch to 3/4 of an inch. This is a nice range and will be able to drill most things in a home workshop. The lettering, for each step, is a bit hard to read in person, but looks better in the photo. It is kind of a dark yellowish color and not bright enough to easily read. The range of the step drill is located on the shaft and is much easier to read, perhaps because it is shown on a lighter color steel, while each step is written on the dark colored bit itself. All in all, this is a very good bit and will work very well doing its job.