OEHT (octagonal) Insert

February 18, 2021
Insert Features High Number of Cutting Edges for Stainless Steel Milling

The Pramet stainless steel milling range offers versatility and productivity. Insert styles include OEHT (octagonal), REHT (round) and XEHT (wiper). The versatile design of the new double positive 45° milling cutter (S450E) allows the same cutter body to be used with both octagonal inserts for face milling and round inserts for face/copy milling applications as well as supporting internal coolant delivery.

Suitable for use on machines with limited power, the combination of new inserts and cutter delivers high metal removal rates with low cutting force and reduced chatter.

It features positive axial and radial face angles for good cutting action and directing chips away from the work-piece. Available in a variety of diameters, the S450E performs well with fragile work pieces, unstable fixturing or preventing stainless steel work hardening.

Utilizing eight cutting edges, the highest number available for positive inserts, the new OEHT (octagonal) insert features four new sharp, positive geometries for various cutting conditions:

  • MF is for finishing applications in stainless steel, mild carbon steel and non-ferrous metals
  • MM is for machining stainless steel in medium cutting conditions
  • M is with stabilizer - suitable for difficult cutting conditions in materials such as carbon steels and harder stainless steel
  • FA is for finishing and light to medium machining of non-ferrous materials

The new geometries offer reduced cutting forces and increased durability for machining with or without coolant. 

Related Glossary Terms

  • carbon steels

    carbon steels

    Known as unalloyed steels and plain carbon steels. Contains, in addition to iron and carbon, manganese, phosphorus and sulfur. Characterized as low carbon, medium carbon, high carbon and free machining.

  • chatter

    chatter

    Condition of vibration involving the machine, workpiece and cutting tool. Once this condition arises, it is often self-sustaining until the problem is corrected. Chatter can be identified when lines or grooves appear at regular intervals in the workpiece. These lines or grooves are caused by the teeth of the cutter as they vibrate in and out of the workpiece and their spacing depends on the frequency of vibration.

  • coolant

    coolant

    Fluid that reduces temperature buildup at the tool/workpiece interface during machining. Normally takes the form of a liquid such as soluble or chemical mixtures (semisynthetic, synthetic) but can be pressurized air or other gas. Because of water’s ability to absorb great quantities of heat, it is widely used as a coolant and vehicle for various cutting compounds, with the water-to-compound ratio varying with the machining task. See cutting fluid; semisynthetic cutting fluid; soluble-oil cutting fluid; synthetic cutting fluid.

  • cutting force

    cutting force

    Engagement of a tool’s cutting edge with a workpiece generates a cutting force. Such a cutting force combines tangential, feed and radial forces, which can be measured by a dynamometer. Of the three cutting force components, tangential force is the greatest. Tangential force generates torque and accounts for more than 95 percent of the machining power. See dynamometer.

  • gang cutting ( milling)

    gang cutting ( milling)

    Machining with several cutters mounted on a single arbor, generally for simultaneous cutting.

  • hardening

    hardening

    Process of increasing the surface hardness of a part. It is accomplished by heating a piece of steel to a temperature within or above its critical range and then cooling (or quenching) it rapidly. In any heat-treatment operation, the rate of heating is important. Heat flows from the exterior to the interior of steel at a definite rate. If the steel is heated too quickly, the outside becomes hotter than the inside and the desired uniform structure cannot be obtained. If a piece is irregular in shape, a slow heating rate is essential to prevent warping and cracking. The heavier the section, the longer the heating time must be to achieve uniform results. Even after the correct temperature has been reached, the piece should be held at the temperature for a sufficient period of time to permit its thickest section to attain a uniform temperature. See workhardening.

  • milling

    milling

    Machining operation in which metal or other material is removed by applying power to a rotating cutter. In vertical milling, the cutting tool is mounted vertically on the spindle. In horizontal milling, the cutting tool is mounted horizontally, either directly on the spindle or on an arbor. Horizontal milling is further broken down into conventional milling, where the cutter rotates opposite the direction of feed, or “up” into the workpiece; and climb milling, where the cutter rotates in the direction of feed, or “down” into the workpiece. Milling operations include plane or surface milling, endmilling, facemilling, angle milling, form milling and profiling.

  • milling cutter

    milling cutter

    Loosely, any milling tool. Horizontal cutters take the form of plain milling cutters, plain spiral-tooth cutters, helical cutters, side-milling cutters, staggered-tooth side-milling cutters, facemilling cutters, angular cutters, double-angle cutters, convex and concave form-milling cutters, straddle-sprocket cutters, spur-gear cutters, corner-rounding cutters and slitting saws. Vertical cutters use shank-mounted cutting tools, including endmills, T-slot cutters, Woodruff keyseat cutters and dovetail cutters; these may also be used on horizontal mills. See milling.