Bhandari, V. B. (2007), Design of machine elements (2nded.), Tata McGraw-Hill, p.340, ISBN 978-0-07-061141-2. Drive shafts on vehicles and power take-offs use splines to transmit torque and rotation and allow for changes in length. Splines are ubiquitous in aerospace, due to the spline's higher reliability and fatigue life compared to keyed shafts. In the computer science subfields of computer-aided design and computer graphics, the term spline more frequently refers to a piecewise polynomial ( parametric) curve. Splines are popular curves in these subfields because of the simplicity of their construction, their ease and accuracy of evaluation, and their capacity to approximate complex shapes through curve fitting and interactive curve design. Serrations are employed in instrument drives, valve shafts, and other applications. Helical Splines- Shaping or slotting is largely used for cutting keyways that do not extend through the full length of the part. Like keyseating, shaping uses a single-point cutting tool for cutting, however, shapers are not guided through the cut on a fixed post. As such, shaper cuts are generally more susceptible to deflection than keyseater cuts. [9] Milling [ edit ]

One of the earliest forms of keyseating was done by chiseling. The keyway is roughed out using a chisel and then filed to size; the key is tried frequently to avoid over filing. This technique is long, tedious, and rarely used anymore. [11] Keyed joints [ edit ] P i − 1 ( 0 ) ( t i ) = P i ( 0 ) ( t i ) , P i − 1 ( 1 ) ( t i ) = P i ( 1 ) ( t i ) , ⋮ P i − 1 ( r i ) ( t i ) = P i ( r i ) ( t i ) . {\displaystyle {\begin{aligned}P_{i-1} In interpolating problems, spline interpolation is often preferred to polynomial interpolation because it yields similar results, even when using low degree polynomials, while avoiding Runge's phenomenon for higher degrees. Garfield, Eugene (2007). "The John Scott Award Recipients from 1826 - present" . Retrieved 2007-08-23. To prevent stress concentrations the ends of the splines are chamfered (as opposed to an abrupt vertical end). Such stress concentrations are a primary cause of failure in poorly designed splines. [ citation needed] See also [ edit ]There are two complementary types of spline, internal and external. External splines may be broached, shaped (for example on a gear shaping machine), milled, hobbed, rolled, ground or extruded. There are fewer methods available for manufacturing internal splines due to accessibility restrictions. Methods include those listed above with the exception of hobbing (no access). Often, with internal splines, the splined portion of the part may not have a through-hole, which precludes use of a pull / push broach or extrusion-type method. Also, if the part is small it may be difficult to fit a milling or grinding tool into the area where the splines are machined. If the knots are equidistantly distributed in the interval [ a, b] we say the spline is uniform, otherwise we say it is non-uniform. Short, evenly spaced teeth on involute splines allow for higher strength and more focused tensile properties. Due to their inclination to self-centre, increased structural strength, and simplicity of adjustment to a variety of parameters, they are one of the most often utilised forms of spline shaft. a b c d Keys and Keyways (PDF), archived from the original (PDF) on 2011-06-14 , retrieved 2010-03-19. Shigley, Joseph; Mischke, Charles (1989), Mechanical Engineering Design (5ed.), McGraw-Hill, ISBN 0-07-331657-1.

Broaching is primarily used to cut square cornered internal keyways. The specific broach, bushing and guide are used for each given keyway cross-section, which makes this process more expensive than most of the alternatives. However, it can produce the most accurate keyway out of all the processes. There are three main steps in broaching a keyway: First, the workpiece is set on the arbor press and the bushing is placed in the opening of the workpiece. Next, the broach is inserted and pushed through, cutting the keyway. Finally, shims are placed between the bushing and the broach to achieve the correct depth necessary for the key. [6] Keyseater [ edit ] A keyseater and a sample of various shapes that can be cut Modern keyseating machineThis concludes the Splines key segment for the time being. I hope this has helped you in some way or provided you with some value in return. If so, consider sharing with those in need and bookmarking Engineers Rail for future reference. Wire-cut electrical-discharge machining (EDM) is primarily used for small production lot sizes where either extreme precision is required or other cutting technologies are not readily available. Wire-cut EDM cuts keyways by eroding material away from the workpiece through a series of rapid electric current discharges between a spooling wire and the workpiece through a dielectric liquid. Computer numerical control (CNC) wire-cut EDM machines allow for a wide variety selection of keyways to be cut, inclusive of multiple keyways on the same hub. The main limitations of CNC wire-cut EDM is the time it takes to cut a keyway as well as the size of parts a given wire-cut EDM machine can accommodate. [9] Shaping or slotting [ edit ] The sides of the evenly spaced grooves are involute, but not as tall as an involute gear. By reducing tensile stress, the curves boost strength.