How to Select an End Mill
- 1). Choose a four flute coarse tooth rougher for hogging out steel. Depending on the radius you need while cutting, four tooth roughing cutters come in many sizes from very small to over one inch in diameter. Steel is a very hard material, so the four teeth are necessary to cut it without end mill breakage. These end mills often come with coatings such as titanium nitride to prolong the life of the end mill as well.
- 2). Use a two flute end mill for roughing aluminum. Because aluminum is a soft metal, you can use a two flute end mill for roughing operations. The two flute end mill will allow enough room for the chips to jettison away from the piece as the end mill cuts. Aluminum chips often stick to four flute end mills due to the fast speeds and feeds used for cutting aluminum. No coating is necessary and you can use fine tooth end mills as well as two-flute roughing end mills.
- 3). Use cobalt, four flute end mills for finishing steel and other hard materials. These end mills can withstand great amounts of pressure and are made of a very hard substance. Although expensive, they will provide you with the best finish on steel. They often are coated with aluminum titanium nitride and can be very expensive but will last for many cycles if used and operated properly.
- 4). Use a high-speed steel two flute end mill for finishing aluminum. These end mills are inexpensive and provide the best finish on aluminum. You can run them very fast due to the soft nature of aluminum, but the constant flow of coolant will lower temperatures at the tips of the flutes, prolonging its life. Like all end mills, these come in a variety of sizes from less than 1/8-inch to over one-inch in diameter and can be purchased at a machine tool supply store in your town or online at an industrial supply company such as MSC Direct or Enco.
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