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A line drawing showing some basic concepts of speeds and feeds in the context of lathe work. The angular velocity of the workpiece (rev/min) is called the "spindle speed" by machinists. Its tangential linear equivalent at the workpiece surface (m/min or sfm) is called the "cutting speed", "surface speed", or simply the "speed" by machinists.
A machinist calculator is a hand-held calculator programmed with built-in formulas making it easy and quick for machinists to establish speeds, feeds and time without guesswork or conversion charts. Formulas may include revolutions per minute (RPM), surface feet per minute (SFM), inches per minute (IPM), feed per tooth (FPT).
SFM is a combination of diameter and the velocity of the material measured in feet-per-minute as the spindle of a milling machine or lathe. 1 SFM equals 0.00508 surface meter per second (meter per second, or m/s, is the SI unit of speed). The faster the spindle turns, and/or the larger the diameter, the higher the SFM.
Incorrect speeds and feeds will cause damage to the tool, machine spindle, and even the product. The quickest and simplest way to find these numbers would be to use a calculator that can be found online. A formula can also be used to calculate the proper speeds and feeds for a material. These values can be found online or in Machinery's Handbook.
Making a shipboard manhole cover in the machine shop of the aircraft carrier USS John C. Stennis. Relative motion is required between the tool and work to perform a machining operation. The primary action is at a specific cutting speed. In addition, the device must be moved laterally across the work. This is a much slower motion called the feed.
In mechanical engineering, backlash, sometimes called lash, play, or slop, is a clearance or lost motion in a mechanism caused by gaps between the parts. It can be defined as "the maximum distance or angle through which any part of a mechanical system may be moved in one direction without applying appreciable force or motion to the next part in mechanical sequence."
Engineering fits are generally used as part of geometric dimensioning and tolerancing when a part or assembly is designed. In engineering terms, the "fit" is the clearance between two mating parts, and the size of this clearance determines whether the parts can, at one end of the spectrum, move or rotate independently from each other or, at the other end, are temporarily or permanently joined.
3 angles: clearance angle, wedge angle, rake (chipping) angle; Δr; length and orientation of the bevel; Cutting edge profile with parameters. One of the most important cutting edge parameters is the K factor. It specifies the form of the cutting edge. 1 means a symmetric cutting edge. If the value is smaller than 1 the form is called a waterfall.