Tooling and Toolmaking CUTTING TOOLS Terms and Definitions Machinery's Handbook, 31st Edition
832
ToolContour.— Tools for turning, planing, etc., are made in straight, bent, offset, and other forms to place the cutting edges in convenient positions for operating on differently located surfaces. The contour or shape of the cutting edge may also be varied to suit different classes of work. Tool shapes, however, are not only related to the kind of operation, but, in roughing tools particularly, the contour may have a decided effect upon the cutting effi ciency of the tool. To illustrate, an increase in the side cutting-edge angle of a roughing tool, or in the nose radius, tends to permit higher cutting speeds because the chip will be thinner for a given feed rate. Such changes, however, may result in chattering or vibrations unless the work and the machine are rigid; hence, the most desirable contour may be a com promise between the ideal form and one that is needed to meet practical requirements. Terms and Definitions.— The terms and definitions relating to single-point tools vary somewhat in different plants, but the following are in general use.
Side Rake Angle
End Cutting Edge Angle
Back Rake Angle
Tool Point or Nose Radius
Side Relief Angle
End Relief Angle Side Cutting Edge Angle Fig. 1. Terms Applied to Single-Point Turning Tools
Single-Point Tool: This term is applied to tools for turning, planing, boring, etc., which have a cutting edge at one end. This cutting edge may be formed on one end of a solid piece of steel, or the cutting part of the tool may consist of an insert or tip which is held to the body of the tool by brazing, welding, or mechanical means. Shank: The shank is the main body of the tool. If the tool is an inserted cutter type, the shank supports the cutter or bit. (See diagram, Fig. 1.) Nose: A general term sometimes used to designate the cutting end but usually relating more particularly to the rounded tip of the cutting end. Face: The surface against which the chips bear, as they are severed in turning or planing operations, is called the face. Flank: The flank is that end surface adjacent to the cutting edge and below it when the tool is in a horizontal position as for turning. Base: The base is the surface of the tool shank that bears against the supporting tool- holder or block. Side Cutting Edge: The side cutting edge is the cutting edge on the side of the tool. Tools such as that shown in Fig. 1 do the bulk of the cutting with this cutting edge and are, therefore, sometimes called side cutting edge tools. End Cutting Edge: The end cutting edge is the cutting edge at the end of the tool. On side cutting edge tools, the end cutting edge can be used for light plunging and facing cuts. Cutoff tools and similar tools have only one cutting edge located on the end. These
Copyright 2020, Industrial Press, Inc.
ebooks.industrialpress.com
Made with FlippingBook - Share PDF online