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579:. The workpiece is properly located and then the reciprocating arm is started. Some models have a stationary table so the cutter is fed horizontally into the workpiece, while others have a movable table that feeds the workpiece into a fixed cutter. These machines can cut other straight sided features other than keyways (see the picture). They can also produce
667:
avoids more serious damage to the mechanism that would be costly or difficult to repair. For example, a steel shaft and pulley may employ a brass key. When excessive torque is applied to the joint, the steel edges shear the brass key into two pieces, leaving the pulley spinning loosely on the shaft and relieving the rest of the machine from possible damage.
358:, or tab, for easy removal during disassembly. The purpose of the taper is to secure the key itself, as well as to firmly engage the shaft to the hub without the need for a set screw. The problem with taper keys is that they can cause the center of the shaft rotation to be slightly off of the mating part. It is different from a
594:
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
570:
on a keyseater enters the workpiece from the bottom and cuts on the down-stroke, while the tool on a shaper enters the workpiece from the top and cuts downward. Another difference is a keyseater has a guiding system above the workpiece to minimize deflection, which results in a closer tolerance cut.
430:
Tangent keys are used in high-torque heavy-duty applications. What would have been the side of each keyway forms heels against which the key sits, and transfers force compressively. This latter point means that for reversible motion of the shaft, another key along a tangent outwards in the opposing
277:
would be affected. The latter is particularly important for high speed operation. The more exact fit of the key and keyway also reduces play, and stress concentrations in, and improves the reliability of the key. An additional advantage is a stuck key can be removed from a shaft with a hammer blow,
141:
are the most widely used. They have a square or rectangular cross-section. Square keys are used for smaller shafts and rectangular faced keys are used for shaft diameters over 6.5 in (170 mm) or when the wall thickness of the mating hub is an issue. Set screws often accompany parallel keys
518:
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
397:
bushings are keyed hub fittings which provide three threaded Dutch keyways and two setscrews as Dutch keys, in addition to the rectangular keyway. The Dutch keyways are threaded only on the alternate hub side or shaft side, with a thread clearance hole form on the opposite side. By simply driving
389:
are an alternative Dutch key component, instead of solid dowel pins. A spring pin is self-fastening and does not work loose under vibration. Hollow spring pins provide a weaker shear strength than a solid dowel pin, and the strength may be varied by varying the wall thickness. This limited shear
666:
is a feature intended to fail and avoid further damage should the machinery be accidentally operated in excess of its design limits. Shear keys may be any of the designs described above, but are made from a weaker material than the shaft. The shear key is easily and inexpensively replaced, and
610:
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
268:
keyway with the remainder fitting into a longitudinal slot keyway in the mating part. The circular segment can be cut directly by plunge cutting with a circular
Woodruff cutter without any reliefs. The main advantage of the Woodruff key is the elimination of milling near shaft shoulders, where
599:(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.
456:
is the creation of the slots in the mating items. Keyseating can be done on a variety of different machines including a broach, a keyseater, wire-cut EDM, a shaper or vertical slotting machine, either a vertical or horizontal mill, or with a chisel and file.
421:
These types of keys are generally attached to the driving member (e.g. shafts). These types of keys have less strength as compared with the sunk keys. These are rarely used keys, to transmit lower power to the driven members (e.g. couplings)
383:, which is driven in and optionally finished by cutting or grinding flush with the end of the shaft. If a straight Dutch keyway hole is optionally tapped with a thread, then an ordinary screw serves as the threaded Dutch key.
378:
features a circular keyway hole (instead of rectangular), produced by drilling axially into the assembled hub and shaft, with a metal dowel pin serving as the key. If the hole and key are tapered, the key is referred to as a
402:) bushings work similarly, but place a circular pattern of three unthreaded and three fully threaded holes further out from the shaft axis on a bushing flange, instead of across the bushing-to-hub interface.
431:
direction is needed. Typically this will be offset by 90° or 180° on the shaft. The key may be wedge, rectangular, or square shaped, but particularly rectangular double-taper keys are used.
278:
the circular profile will push the key out of the slot, as opposed to a standard key which will need to be pushed axially, or pulled out of its slot. Common applications include
398:
setscrews into selected holes, the hub mechanism conveniently operates to rigidly lock or definitely release from the shaft, without hammering or hub-pulling. Quick-disconnect (
390:
strength specification is designed to sustain normal operation, but then give way in the event of excessive shaft torque, thus protecting the rest of the machine from damage.
354:
The tapered key is tapered only on the side that engages the hub. The keyway in the hub has a taper that matches that of the tapered key. Some taper keys have a
748:
523:
and the bushing is placed in the opening of the workpiece. Next, the broach is inserted and pushed through, cutting the keyway. Finally,
673:
Improperly machined keyways that had cutter deflection or drifting occur, may not be strong enough for the required application.
1019:
160:
338:
713:
393:
Introducing an additional bushing component between hub and shaft improves the performance and convenience of keyed joints.
898:
Kibbe, R. R. (1995). Machine tool practices. (5th ed. ed., p. 572). Englewood Cliffs, New Jersey: Prentice-Hall, Inc.
790:
654:
to size; the key is tried frequently to avoid over filing. This technique is long, tedious, and rarely used anymore.
877:
148:
172:
1014:
591:
142:
to lock the mating parts into place. The keyway is a longitudinal slot in both the shaft and mating part.
810:
326:
973:
993:
829:
Krar, S. F. (1983). Machine tool operations. (pp. 84–85). New York: Gregg
Division McGraw-Hill.
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are placed between the bushing and the broach to achieve the correct depth necessary for the key.
314:
638:
For internal keyways that are not too long, the keyways can be milled if a radius is acceptable.
20:
703:
362:
in that tapered keys have a matching taper on the keyway, while tapered shaft locks do not.
270:
487:
8:
440:
410:
39:
transmission. For a key to function, the shaft and rotating machine element must have a
988:
670:
Two parallel keys can be used if the shaft connection requires a higher torque rating.
475:
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67:
265:
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47:, which is a slot and pocket in which the key fits. The whole system is called a
28:
572:
291:
1008:
952:
879:
Cutting
Keyways - Broaching, Keyseating, Wire-Cut EDM, Shaping, & Milling
562:, are specialized machines designed to cut keyways. They are very similar to
524:
274:
839:
567:
519:
three main steps in broaching a keyway: First, the workpiece is set on the
279:
983:
445:
This type of key uses multiple keyways in the hub to transmit high power.
35:. The key prevents relative rotation between the two parts and may enable
651:
520:
406:
301:
32:
631:
or slotting cutters are used for parallel and tapered keyways, while a
583:
slots, which are slots that do not extend through the whole workpiece.
535:
386:
287:
283:
261:
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but with the teeth on the end of the shaft instead of on the surface.
294:
51:. A keyed joint may allow relative axial movement between the parts.
682:
628:
63:
943:(Revised 7th ed.). New York: John Wiley & Sons. pp.
300:
This type of key was developed by
William N. Woodruff of Hartford
571:
The process starts by clamping the workpiece to the table with a
586:
647:
607:
563:
59:
36:
543:
623:
Parallel, tapered, and
Woodruff keyways can be produced on a
16:
Machine element used to connect a rotating element to a shaft
576:
55:
539:
A keyseater and a sample of various shapes that can be cut
344:
Gear G is positively located on shaft S by
Woodruff key N
304:. In 1888, he was awarded the John Scott Medal by the
811:"The John Scott Award Recipients from 1826 - present"
650:. The keyway is roughed out using a chisel and then
646:
One of the earliest forms of keyseating was done by
919:Romig, J. V. (1926). The Popular Science Monthly.
1006:
1000:Drawing and standard dimensions of keys Gardette
872:
870:
31:used to connect a rotating machine element to a
979:ASME recommended key sizes for inch based units
860:Wick, C. H. (1964). Versatility of keyseating.
708:(2nd ed.), Tata McGraw-Hill, p. 340,
780:
867:
799:
774:
592:Wire-cut electrical-discharge machining (EDM)
587:Wire-cut electrical-discharge machining (EDM)
595:the workpiece through a dielectric liquid.
166:A sprocket with an internal parallel keyway
781:Shigley, Joseph; Mischke, Charles (1989),
154:The keyseat in a shaft for a parallel key
805:
701:
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907:
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178:Cross-section of a parallel keyed joint
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743:
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78:There are five main types of keys:
13:
974:Standard Metric Keys & Keyways
54:Commonly keyed components include
14:
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937:Leonard, William Samuel (1919) .
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940:Machine-shop Tools and Methods
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635:is used for Woodruff keyways.
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1:
1020:Mechanical power transmission
783:Mechanical Engineering Design
688:
566:; the difference is that the
448:
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641:
530:
510:
7:
921:The Popular Science Monthly
785:(5 ed.), McGraw-Hill,
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101:
10:
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705:Design of machine elements
618:
597:Computer numerical control
438:
994:Great Soviet Encyclopedia
547:Modern keyseating machine
365:
332:A Woodruff key and keyway
702:Bhandari, V. B. (2007),
505:Different slotting tools
320:A Woodruff key installed
264:, fitting partly into a
73:
548:
540:
21:mechanical engineering
1015:Hardware (mechanical)
864:(NY), 70(8), 138-140.
615:than keyseater cuts.
546:
538:
271:stress concentrations
251:is the shaft diameter
106:Types of sunk keys:
984:What is keyseating?
923:., 110(5), 72, 124.
603:Shaping or slotting
556:keyseating machines
441:Spline (mechanical)
308:for his invention.
549:
541:
360:tapered shaft lock
306:Franklin Institute
260:Woodruff keys are
989:Key joint article
715:978-0-07-061141-2
245:is the key height
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807:Garfield, Eugene
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756:, archived from
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750:Keys and Keyways
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564:vertical shapers
554:, also known as
502:
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409:is similar to a
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266:circular segment
239:is the key width
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792:0-07-331657-1
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956:. Retrieved
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931:Bibliography
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908:Leonard 1919
903:
894:
883:, retrieved
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856:
845:, retrieved
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814:. Retrieved
801:
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765:, retrieved
758:the original
749:
729:Leonard 1919
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658:Keyed joints
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568:cutting tool
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426:Tangent keys
420:
411:spline joint
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350:Tapered keys
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521:arbor press
417:Saddle keys
407:Hirth joint
387:Spring pins
302:Connecticut
288:snowblowers
108:rectangular
49:keyed joint
1009:Categories
885:2014-12-03
847:2010-01-30
841:Keyseating
816:2007-08-23
767:2010-03-19
689:References
613:deflection
552:Keyseaters
454:Keyseating
449:Keyseating
435:Spline key
395:Taper-Lock
372:Scotch key
295:propellers
284:automotive
953:848146647
862:Machinery
664:shear key
648:chiseling
642:Chiseling
629:End mills
531:Keyseater
516:Broaching
511:Broaching
381:Dutch pin
376:Dutch key
64:couplings
958:30 April
809:(2007).
683:Coupling
677:See also
128:Woodruff
120:gib-head
102:Sunk key
619:Milling
608:Shaping
573:fixture
227:
212:
203:
189:
124:feather
88:tangent
68:washers
60:pulleys
45:keyseat
951:
789:
712:
366:Others
292:marine
273:, and
232:where
126:, and
112:square
96:spline
94:, and
84:saddle
66:, and
43:and a
41:keyway
37:torque
945:39–42
761:(PDF)
754:(PDF)
652:filed
581:blind
525:shims
92:round
74:Types
56:gears
33:shaft
27:is a
960:2019
949:OCLC
787:ISBN
710:ISBN
577:vise
558:and
290:and
80:sunk
23:, a
575:or
374:or
356:gib
25:key
19:In
1011::
947:.
869:^
736:^
662:A
627:.
405:A
400:QD
370:A
297:.
282:,
210:=
187:=
130:.
122:,
118:,
114:,
110:,
98:.
90:,
86:,
82:,
70:.
62:,
58:,
962:.
888:.
850:.
819:.
795:.
770:.
718:.
249:d
243:H
237:W
224:3
221:/
217:d
215:2
208:H
200:4
197:/
193:d
185:W
Text is available under the Creative Commons Attribution-ShareAlike License. Additional terms may apply.
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