Many companies have unique needs for their applications. We realize the myriad of end mills we offer at Conical Tool Company needs charts and technical data to help you decide which end mill best suites your needs. We also have RPM and feed-rate charts to help with your decision. Things like draft angle per side, included angle, taper angle, tip size and configurations, flute length, large diameter, and shank diameter specifications can be confusing. We have added a full page of technical information on this website to assist you. All high speed steel end mills are produced from premium grade, high speed steels, heat treated to a high Rockwell, for shock and abrasion resistance. Carbide end mills are produced with all virgin micro-grain carbide powder produced through an extrusion-only process which results in a lower chance of fracturing, then using a 1200 grit ground to a high grade h6 polish for shrink fit collets.


Charts, formulae, and general information on these pages should guide you to choose the correct end mills, tapered end mills and / or cutters. Our standard end mills are designed for side milling, plunging, slotting, and interpolating around the inside of a cavity. If reaming a hole in tough materials, they may chatter and grab into the side wall. In these instances, we prefer to make special end mills with a slow 12° right-hand spiral. If you are reaming a large enough through-hole, a left-hand spiral end mill would provide less chatter and improved surface finish due to the downward direction the chips would travel in. All end mills, tapered end mills, and cutting tools are breakable, but a judicious selection will minimize breakage. The greater the length of the end mill compared to its diameter, the more fragile it is. Use an end mill with as short a flute as possible. Short end mills cut fast and free, lessening the hazard of breakage. When long, slender end mills and tapered end mills must be used, a light cut is called for.

Because of the varying diameters of Conical tapered end mills, spindle speed and feed rate cannot be accurately recommended. Generally, you are right to run Conical tapered end mills at the highest possible speed that does not produce heat-discolored chips. Feed the end mill slowly enough to let the cutter do the cutting. Feeding too fast can cause broken tips and chipped flutes. When you use coolant or air on the end mill, you can increase spindle and feed rates.

Carbide material is premium micro-grain carbide. Taper angles remain constant to tolerances of +/-.002” per inch of flute, regardless of the end mill’s diameter or length, even after resharpening. Tip tolerances are held at +/- .002” (.001” for straight end mills). Shank tolerances are -.0002” to .0005”. Constant helices of right hand spirals range between 28° for smaller end mills, 25° for larger and steeper tapers. Constant helices of left hand spirals range between 15° and 18°.

Conical Tool Company has always welcomed the chance to produce custom end mills or tapered end mills to your own specifications. We have over-runs on many special end mills produced for other companies. Check with us early, we may have your answer in our stock room.