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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).
Cutting speed may be defined as the rate at the workpiece surface, irrespective of the machining operation used. A cutting speed for mild steel of 100 ft/min is the same whether it is the speed of the cutter passing over the workpiece, such as in a turning operation, or the speed of the cutter moving past a workpiece, such as in a milling operation.
The Marshall-Edgeworth index, credited to Marshall (1887) and Edgeworth (1925), [11] is a weighted relative of current period to base period sets of prices. This index uses the arithmetic average of the current and based period quantities for weighting. It is considered a pseudo-superlative formula and is symmetric. [12]
For both of these rules of thumb (85%/90% and major minus pitch), the tap drill size yielded is not necessarily the only possible one, but it is a good one for general use. The 85% and 90% rules works best in the range of 1 ⁄ 4 –1 in (6.4–25.4 mm), the sizes most important on many shop floors. Some sizes outside that range have different ...
It relates to spindle speed via variables such as cutter diameter (for rotating cutters) or workpiece diameter (for lathe work). SFM is a combination of diameter and the velocity ( RPM ) 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 ...
The material removal rate in a work process can be calculated as the depth of the cut, times the width of the cut, times the feed rate. The material removal rate is typically measured in cubic centimeters per minute (cm 3 /min).
Safe running speeds for various nut materials and loads on a steel screw [17] Nut material Safe loads (psi) Safe loads (bar) Speed (fpm) Speed (m/s) Bronze 2,500–3,500 psi 170–240 bar Low speed Bronze 1,600–2,500 psi 110–170 bar 10 fpm 0.05 m/s Cast iron 1,800–2,500 psi 120–170 bar 8 fpm 0.04 m/s Bronze 800–1,400 psi
Is it correct to pluralize them, or should it be speed and feed? Wizard191 19:11, 1 December 2008 (UTC) Either one would work, but I vote for "speeds and feeds" because it is a well worn set phrase. — ¾-10 01:31, 2 December 2008 (UTC) That's what I was looking for. I'm no machinist, so I'm not sure what the common terminology is.