Keyway Width. powerhound (Mechanical) 10 Mar 08 23:14. 2 MATHEMATICAL FORMULATION AND FE The torsional moment is given by M t~GJ w l ð1Þ Fig. 010 Height (d) (t) - DIM Keyway Width (w) AGMA 9002-A86 Inch Bore and ANSI B17. Standard Metric Keys & Keyways for Metric Bores with One Key • Couplings (Page 2 of 2) All Types 427-140 Reo a 21 (P eso) oola e el 11 pesees 2 Telepoe 22 a 22 eoo Key & Keyway Dimensions – Millimeters Coupling Hub Keyway Dimensions – Inches Shaft Diameter “D” Key Size Nominal Keyway Width Hub “W” Keyway Depth Hub “T2” Shaft Diameter vs Key Sizes Design Recommendations. 5020 2. 1 +0. The essential data for this standard have been extracted from ISO Recommendations R 7731) and R 7742). 5 times the shaft diameter to ensure a good load distribution over the entire key length when the shaft becomes twisted when loaded in torsion. Key dimensions: Parallel keys are most commonly used. 125 0. --keyway dimensions Keyway sizing chartDimensions standard keyseat keyway shaft shafts diameter nominal. 25. imperial (pre-war) keyways diameter key shaft hub over incl w h width tol. 3mm 2. Parallel keysKeyway shaft roymech tolerance Shaft standard key sizes rectangular gates keys diameters most non std readily availableParallel metric keys and keyway dimensions. 089 mm. BS 4235-2:1977, ISO 3912-1977: Specification for metric keys and keyways - Woodruff keys and keyways. TruKey® Shafting from Keystone is designed to provide the straightest, most accurate keyed shafting, in the industry. Keyseats and Keyways. AUTOMATION & IIOT. Only informative sections of standards are publicly available. Metric – Rectangular B. Referencing Figure 1, the keyway dimension is W x T1. Nominal dimension of key b x h. 2-1967. Metric Standard Parallel Keyway and Key Sizes Shaft Diameter (mm) Keyway (mm) Key (mm)* From To Width (W) Depth (h) Width (W) Depth (T) 6 8 2 1. It helps to transmit torque. They can be completely disassembled and placed anywhere on a shaft. Get In Touch. 1. 000 so that there is no. The 22 x 14 suggestion makes a lot of sense, unless prevented by thin-walled hubs and/or shaft size issues. Feather key: This is a parallel key with rounded ends. Shafts with keyways can catch clothing easily. 5 Power rating Power ratings of shafts are presented in Tables 2-7. As noted above, when selecting a keyway tolerance, there are two common selections in the metric system. They can be used in transmitting motion and power between two shaft in the same or in opposite directions. 020 0. The keyways are dimensioned for use with a stock key class 2 in order to get a tight fit combination. As noted above, when selecting a keyway tolerance, there are two common selections in the metric system. Referencing Figure 1, the keyway dimension is W x T 1. Top. Height. All keyed Shafting is guaranteed to fit on a bearing, and the ends can be. ) the shaft sizes are known and controlled. Shaft and hub keyway dimensions. Metric keyways are dimensioned by width and depth as measured from the radius of the shaft to the center of the keyway. Ruland manufactures them from select North American bar stock in 2024 aluminum for lightweight and low inertia, 1215 lead-free steel for general purpose use, and 303 stainless steel for high corrosion resistance. 8mm 2. To use this calculator, input your Torque, Shaft Diameter and Key Length values. width depth tol. Keyway toleranceKeyway-and-key-size-dimensions. Design of Square Key and Keyway (Wood Ruff) Stress, Shear and Torque Equations and Calculator. Metric module, side fit. Jul 26, 2022 — by ML Engineering Content Editor in Machine Elements & Structural Engineering Keys and keyways are a very important part of shafts and power. 3mm 5mm 5mm 5mm 5mm 6mm 6mm 6mm 8mm 8mm 22mm 24mm 16mm 17mm 19mm 20mm 25mm Keyway Width (w) 10mm 3mm 3mm 1. 1/4" & 3/8" — 3/32" x 3/64" 1/2" & 9/16" — 1/8" x 3/64"keyways in shaft-hub connection is the shear stress, so the focus is done on it. Over To (Incl. Direct interchange with Spicer 1000 series. Old JIS (Class 2) Standards Unit [mm] Hole diameter b2 t2 Key size b×h; Standard size Tolerance(E9. 75 inches (19. Coupling Length: 11. Shaft Arbor and Keyseat Dimensional Data American National Standard Keys and Keyways; Standard Metric Keys Keyways for Metric Bores with One Key; Keyway Cutter Hole Keyway Dimensional Data for MIlling Centers and Arbors - ANSI/ASME B94. 025 h9-0. 3 Keyseating - The operation of prociucing key- seats. 5. 9-11, and 9-12 Figure 9. Machining of square shafts with rounded ends (with or without keyways) Other machining available upon request per prints provided (drill, tap, threading) For Keyway MM Dimensions – see the table at. Where a key is to be used it should be side fitting with top clearance. Hub keyway b* P9 / N9 / H9 Shaft keyway h t 1 = d + t 2 t 2** t 3 = d – t 4 t 4 6 2 2 2 7 1 +0,1 4,8 1,2 +0,1 7 2 2 2 8 1 +0,1 5,8 1,2 +0,1. A shaft narrower than the applicable shaft diameter should not be used. 3 Keys and Keyways P gear d T a b bearings are self-aligning l so act as simple supports FIGURE P9-3 P9-03. Square Drives for Socket Tools ASA B5. ISO/TC 14. D (Ø) Overall Length (mm) Body Material. Keyway dimension Reference; b h C l Basic dimen sion of b 1 and b 2 Sliding type Normal type Fastening type r 1 and r 2 Basic dimen sion of t 1 Basic dimen sion of t 2 Allow ance t 1 and t 2 Compliant shaft diameter d; Basic Dimen sion Allow ance (h9) Basic Dimen sion Allowance b 1 b 2 b 1 b 2 b 1 and b 2; Allow ance (H9) Allow ance (D10). all dimensions in inches. 4 Splines 9. Standard sizes in diameters from 3/8″ to 2 1/2″. Unless otherwise specified, the shaft keyway is assumed. 16-0. If your measuring from the OD of the shaft there is a formula in Machinery Handbook to add that dimension to the half size of the key but don't depend on it for the right depth to cut to. It might be worth roughing the keyway underwidth by 1/16" and then profile cut both sides with a nice sharp carbide to straighten. Contact. shaft diameter Dimension d Allowance (h9) Allowance dimension (D10) 2×2 2 0-0. This is measured at the wall height not the depth of the cut from first contact with the diameter. (i. The keyway is usually manufactured by a vertical or horizontal milling cutter. 2 mm, but the shaft had a keyway. Technical Data: rated torque from 10 - 800 Nm shaft diameter from 5 - 72 mm. 4375 1. Coupling in mechanical engineering is a device used to connect two shafts together at their ends for the purpose of transmitting power or torque. Author: Melyssa Kotecki Created Date: 4/29/2019 2:23:20 PM. H-M Supporter Gold Member. G&G Manufacturing Company 4432 McKinley Street P. 1 9 3 +0. These tables can be used to find the approximate shaft diameter for various service conditions. BS 46 Part 1 : 1958 Square Keys and keyway Dimensions. ). G&G Manufacturing Company 4432 McKinley Street P. Position on shaft. Appropriate fits can be established for each shaft size and published in a standard. 38 1. Standard Keyway Size X/S Shaft/Bore Diameter. Use the keyways with machine keys to transmit torque to gears, sprockets, and other keyed components. Shaft /Hub/keyway material (BS EN 10083 C45 normalised. The dimension from the top of the keyway to the opposite bore side. 3/32" key depth (standard square keystock size for the shaft is 3/16") 1044 stress proof steel series, 303. The intention of the keys/keyways is to allow axial motion of a female sleeve to which the keys are mounted while preventing rotational motion. The centuries-old industry standard shaft-to-hub mounting technique is the key and keyway. Rectangular-faced keys are used for larger shaft diameters and square keys are used for shafts smaller than 6. Figure 1 - Keyway and Key Size Dimension Reference. 110 mm to 140 mm – 15 mm step. Keys standard metric keyways mechanicalMetric keyway shaft depth reference dimensions diameter iso r773 width Metric woodruff keys are supplied to din 6888 / iso 3912 in c45k keyKeyway metric dimensions keys. This is why you remain in the best website to look the incredible ebook to have. T h i s standard establishes a uniform relation-ship between shaft s i z e and key s i z e for parallel 2 . 1 . Shaft Size. Nominal Dia. Likewise, the keyway height must be 3. 010". --Satyanarayan Gangaram Pitroda Addeddate 2013-09-10 07:34:16Standard Calculator Bore Size. The first is Js9. Metric standard parallel keyway and key sizes shaft diameter (mm) keyway (mm) key (mm)*. Inspection methods for straight and tapered bores and. A frictional connection between shaft and component solves the problems associated with backlash, and additionally eliminates the machining operations required for keyways. This is an undersized clearance. 025 mm and +0. BS 5686:1986, ISO 14-1982: Specification for straight-sided splines for cylindrical shafts: metric nominal dimensions, tolerances and gauging requirements. The introduction of a DIN or ANSI standard keyway into a shaft normally reduces the shaft radius by 20 to 25%, and often as much as 50%. Drive Type Fastenings without Taper Action; Parallel Keys, Keyways, Deep Pattern. Mount the adapter to the workpiece shaft using a full key in the shaft keyway and fill the half-key void in the opposite side of the adapter with a half-key (see Figure 6-22 B). Dimensions of shaft keys, standardized many years ago, are commonly considered to be the main concern in applying these devices. Standard and metric keyway broachesTable aii-12. As a general rule, the key is a tighter fit to the shaft so that the key remains on the shaft during assembly and removal. This shaft key installation requires a keyway on the hub and it does not require any keyway on the shaft. 2 Cross-section of prismatic part of parallel key-way, the coordinate system is placed at the shaft axis. 5 to 4. It is ideal for overhung or unsupported shafts and is an excellent way to attach items such as mixer paddles and shaft Bore Diameter 1: 1. . Get a quote +61 7 3271 5424. For more information, to get a formal quote on 2-15/16" keyed shaft, or for pricing on any of its accompanying components/ accessories please contact us and we will be happy to assist you. Cutting an internal keyway can be a challenging task, but with the right method and tools, it can be done with precision and efficiency. The following tables show standard dimensions for keys and their. Keyway metric key dimensions standard keyways keys bores shaft hub depth iso diameter engineering table edge width millimetersWoodruff ansi fasteners nominal Woodruff ansi metric keyway fasteners nominalParallel dimensions metric keyway key keys 1972. 3mm. This key stock is undersized, so keys will fit slightly more loosely than standard keys and are best for inconsistent keyways. Further, shafts, along with any other required drive elements, can be made smaller once the keyway notch factor is removed. 4 Prior to mounting the hubs, place the keys in the shaft keyways. Title: Tables. comParallel Shaft Keys. In reply to #10. This type of key is used in areas where frequent removal of the key is necessary. The key and key seat cross section are ISO standardized. British Standard Metric Keyways for Square and Rectangular Parallel Keys 11 5/16 3/8 7/16 1/2 3/4 3/4 7/8. ANSI Woodruff Keys. 003-0. 5000 2. Only informative sections of standards are publicly available. Transmission shafts standard sizes or lengths (according to steps). 020 0. Tolerance each on T1 and T2 is -. %PDF-1. If a key is to be fitted place it in the shaft keyway before fitting the bush. 010". The common specification dimension, Key Size, is highlighted. d w +0. 6. The keyway on the. This article provides a table below that shows the standard dimensions (sizes) for square and rectangular cross-section sunk keys. 01~50. 1. 3/32. 000 / +. 010 0. Height. Standard Metric Keys and Keyway Bores. 2. This specification includes index tolerances for multiple keyways. Carbon steel (AISI-1045) or stainless steel (T304 or T316) Custom shaft sizes and key sizes. Stocked in: Steel; Stainless Steel; Specifications. Here, a case study taken on ball mill shaft keyway for investigation of stress concentration factor. In general, also, we use this type in low-speed applications. 180. Standard keyways provide added torque capacity and fixed shaft phasing. It is true that these ANSI standards define different products than ISO specs. . Good Answers: 102. Hub keyway depth is one-half the nominal height of the key and measured from the side corner. The common specification dimension, Key Size, is highlighted. He explains that for specifying keyways, it must be noted that there are very well established standards for dimensions, which can be found in Machinery’s Handbook, or ANSI B17. 18 1. 2-1967 Specification for metric keys and keyways – Parallel and taper keys BS 4235. 062 0. 1-1943 standard. The centre of the pair should be opposite the keyway if a key is used with the set screws bearing on a slight relief turned in the shaft or a pair of flats. Design of Square Key and Keyway (Wood Ruff) Stress, Shear and Torque. Description: Designed for aligned shafts, the 1-Piece Clamp-Type Coupling makes two shafts function as one. The keys are square or rectangular. - Series F couplings supplied with 4) All dimensions per AGMA 9002-A86Standard keyway sizes chartStandard keyway dimensions Metric key keyway dimensions per iso/r773. Nominal Shaft Diameter Nominal Key Size Normal Keyseat Depth Over Up to and Incl. Straight keys, with a square or rectangular cross section, are the most common type of key. The keyway in the shaft is in the form Of a semicircular recess with the same Fig. 1 Square Keyway Tolerances Minimum 2. It also gives the relationship to be observed between the diameter of the shaft and the section of the key for. NOMINAL SHAFT DIAMETER BOTTOM OF SHAFT TO BOTTOM OF KEYWAY WIDTH. This is an undersized clearance. The dirncnsions of tangential keys and keyways shall be as given in Table 7. Referencing Figure 1, the keyway dimension is W x T1. 14. A further disadvantage to shaft keys in a world of increasingly compact motion components is the reduction in the torque density of the shaft and its respective locking element. Woodruff keys work well near shaft shoulders and on tapered shafts. British Standard :BS 46 Part 1 : 1958 Keys and keyways and taper pins. If the enduser is using oversize plated keystock, then the properly centered keyway is more important. MISUMI USA has all of your Universal Joints needs covered, with over 3. 1-1967, ASME standard B17. Reference 'Machinery's Handbook'. That's also a condensed version. 3125 0. In manufacturing upon 6885 Information used with permission ot Martin 02007 Shatt Keyseats/Hub Keyways Standard Keyseats/Keyways Sra' IoW Square Keyways Metric: WxHKey W x T2 Keyway American Standard — Inches ShanScenario: The exposed round shafts are completely smooth and have no bolts, holes, or keyways. ANSI/AGMA 9002-A86 was based upon the design criteria related to bores and keyways in coupling hubs that had evolved over many years of successful industry practice. 46 : PART 1 : 1958. If the enduser is using oversize plated keystock, then the properly centered keyway is more important. KEYSHAFT Keyed Shaft, Diameter 3/4 in, Keyway 3/16 in x 3/32 in. Welcome Location Transmission Bushes Pulleys Belts Vector Belts Roller Chain & Sprockets. The key can be withdrawn at will to disengage the mating components. Use the middle of the shaft with bearings and other round-bore components. The corresponding shaft tolerance needs to be determined based on whether the fit between the gear and shaft is to be an interfer-ence fit, a transition fit, or a clearance fit. 012: 4: 0 -0. They conform to ANSI B17. 1 mm) in diameter. 19-1997; Design of Square Key and Keyway (Wood Ruff) Stress, Shear and Torque; Parallel Key. ANSI B17. Referencing Figure 1, the keyway dimension is W x T 1. We stock pre keyed shafting in many diameters, including metric diameters, with standard keyways. 414 Maximum 2. Metric External Table Chart Thread Designations Sizes M 1. 020 0. We carry a wide range of products with keyways, including bushings and roller chain sprockets. Key (engineering) In mechanical engineering, a key is a machine element used to connect a rotating machine element to a shaft. 1/2 to 3/16. Keyway metric key iso dimensions standard keyways keys r773 pdf bores shaft hub depth diameter standards engineering table edge widthKeyway tolerances bore Keyway dimensions table aiiShaft standard key sizes rectangular gates keys diameters most non std readily available. To confirm the status of any standard, identify the replacement standard if it is obsolete and/or purchase the standard please use. 219 (c) (5) (ii) The vertical clearance in passageways between the floor and power transmission beams, ceiling, or any other objects, is not less than five feet six inches (5 ft. is very difficult to write one universal bore and keyway standard to address the many combinations. For instance, if standard tolerancing on stainless keys is, say, 0. There are generally two keys we place between the shaft and hub as a tangency. 28. and bending for range of shaft diameters from 10 mm to 500 mm as per standard sizes. Same deal if using a pulley/shaft/sprocket with a taper lock hub. Check Details. Keyway Bore Diameter Size Bore Reference -0. clearance fit bores with set screws. Shaft and hub keyway dimensionsKeyways shaft keyway coupling shafts drive apart rotate two installing should asked driver question common am if when. Key Stock is cold drawn to exacting tolerances with sharp corners, perpendicular and parallel sides, and smooth, bright surface finishes. 3mm 3. • Machine elements such as gears, pulleys (sheaves), flywheels, clutches, and sprockets are mounted on the shaft and are used to transmit power from the driving. Shaft Dia. Check Details. Shaft standard key sizes rectangular gates keys diameters most non std readily availableMetric key keyway shaft standard keyways falk keys bores resources industrial Shaft and hub keyway dimensionsKey allen hex wrench keys set bolts types alley supply competitive prices details alibaba fairwell. Measure the overall length of the boss (hub) of propeller Measure the keyway width. Keyway misumiKey and keyway dimensions (control in motion) Keyway sizing chartMetric key keyway dimensions. 6 mm. O. constitute provisions of this Standard: PAES 305:2000, Keys and Keyways for Agricultural Machines 3 Application Spur gears are used to connect parallel shafts and have teeth formed in cylindrical blanks parallel to the shaft axis. 3D Printing & CAD. Keyseat is a recess in the shaft and the Keyway is the recess in the hub to receive the key and thus securely lock the component. 1 - 114. 1. To view the full content, you will. Keyway metric dimensions key iso tolerance js9 r773 width per depth hub t2 height radius text mill question answered hasnSolved 5. 18 1. Hex, round, and step profiles are available to mate. Shaft and hub keyway dimensionsKeyways shaft keyway coupling shafts drive apart rotate two installing should asked driver question common am if when What are shaft keyways. sometimes referred to as a keyway. R R Cutter Run-out. The standard lengths for shafts are 5m, 6m, and 7m, but they are usually taken as 1m to 2m. Check Details. In addition to diameter tolerances that are twice as tight as standard keyed shafts, these shafts include a traceable lot number and test report. Keyway dimensionsKeyway sizing chart Metric stepper motor shafts size data tableMetric key keyway dimensions per iso/rtt3 js9 width. The standard keyway depth in the shaft is 1/2 the keystock size. 000 +. A keyed joint is used to ensure orientation or restrict rotational movement between parts, as in the case of joining a shaft with a coupling. It is a rotating member, in general, has a circular cross-section and is used to transmit power. keyways in the shaft members than to keyways in coupling hub bores. Just seeking opinion on using a true position on a key way slot on a round shaft. keyway dimensions metric keyways diameter key shaft hub over incl w h width depth tol. Drive shaft Design, key and Keyways. The same dimensions as our Clamp-Type Shaft Couplings, these Clamp-Type Couplings with keyways are available from stock with standard keyways. A capital letter refers to the hole size and lower-case letter refers to the shaft size. Regards Tyrone. 46 : Part 1 : 1958 DLMENSIONS OP TANGENTIAL KEYS AND KEYWAYS. Choose from our selection of rectangle keys, including over 950 products in a wide range of styles and sizes. where, the Standard Dimension for key = 14mm x 9 mm. Keys shaft rectangular types key chart hub designs tapered machine selectionStandard keyway size chart Metric woodruff keys are supplied to din 6888 / iso 3912 in c45k. Keyshaft keyed shaft, diameter 1 7/16 in, keyway 3/8 in x 3/16 inKeyway parallel keyways metric t2 wxh bores Keyway keyed keyways boresGates belts, hoses, and applications: standard & non-standard shaft key. Standard keyways provide added torque capacity and fixed shaft phasing. Undersized Key Stock Assortments. See dimensions W and h in Figure 1. Metric – Rectangular B. 6 1. TruKey® Shafting from Keystone is designed to provide the straightest, most accurate keyed shafting, in the industry. 120. DIN 6885-1 :- Key, Hub Keyway, Shaft Keyway Details and Dimensions. 424 Minimum 2. Metric Standard Parallel Keyway and. 1 Square Keyway Tolerances Minimum 2. Index the adapter 180 degrees on rotor shaft (see Figure 6-22 C). e. As bushing bores approach the maximum recommended diameters, keyway depths are reduced in order to extend maximum bores as much as possible. a) End-milled or prole keyway b) Sled-runner keyway. 3 6. ing can be used for different shaft sizes They are easy to prepare, quick to install and provide a low-cost solution But they are also surprisingly ineffective When keyways are cut into components and shafts, they reduce the cross section (fig 2), and conse-quently the strength of the machined parts Keys and keyways may also require a clearance. 250"+. After cutting a keyway in a shaft, a key is placed in the seat and the two parts can now be mated together. We stock pre keyed shafting in many diameters, including metric diameters, with standard keyways. keyways & keys dimension in accordance with BS 4235-1:1972: Specification for metric keys and keyways - Parallel and taper keysSaddle keys are one of the shaft key kinds that are mounted on the shaft’s surface rather than in the keyway. Finished Striaght bores for standard AGMA Class 1 Clearance fit. 4 2. Unless otherwise specified, the shaft keyway is assumed to be standard. Unless otherwise specified, the shaft keyway is assumed to be standard. Because they're usually shorter than. 1The tables below show the dimensions of a straight sided spline in accordance with BS 5686:1986, ISO 14-1982: Specification for straight-sided splines for cylindrical shafts: metric nominal dimensions, tolerances and gauging requirements. Ruland disc couplings are manufactured in clamp or set screw style, with or without keyways, in bores sizes from 1/8” to 1-1/4” and. Keyways play a crucial role in mechanical systems, enabling power transmission between shafts and other machine elements. The deviations are less than the basic size. Lecture1: Design of Shaft 26. S. The keyway in the hub is made in the usual manner. Key and keyway dimensions (control in motion) Keyway shaft coupling hole service couplings modification additional motion control tapered parallel Keyway chart Standard shaft sizes key bushi. 5000 2. Many industries manufacture the Key by plain carbon steel. . 95 6. BOTTOM OF SHAFT TO BOTTOM OF KEYWAY. 5020 2. 19-1997 1, the Metric key size is W x T. 25. The hub keyway is dimensioned by its width and depth on the shaft – keyway sides. 5 times the shaft diameter to ensure a good load distribution over the entire key length when the shaft becomes twisted when loaded in torsion. All Keyways are parallel and to British Standard 46: Part 1: 1958, with the exception of those marked* which are shallower. 260". The tolerance zone for shaft keyway width b with normal fit is ISO N9 and with close fit ISO P9. 5 1. The depth of the keyway weakens the shaft. These keys have a tapered body that wedges in to the keyway for a more secure fit than standard machine keys. To use a key as a sacrificial part, choose a softer key that will shear off. Haven't seen a standard key or a woodruff key used as a shear point. DIN Standard. British Standard Metric Keyways for Square and Rectangular Parallel Keys 11 5/16 3/8 7/16 1/2 3/4 3/4 7/8 Nominal Diameter, d 6 1/2. 5 in (170 mm). ASME standard B17. We would like to show you a description here but the site won’t allow us. Figure 2 Keyway Sizes. 9. Keyway is not made for holes of less than 12 mm. As with all functions of the Machinist's Calculator, linear values can be. 5 Interference Fits Components can be attached to a shaft without a key or spline by using. The Stafford Manufacturing Corp. The stress concentrations at the keyway end are most severe for the profile keyway, so with respect to fatigue the sled-runner is the best design. Key body. Keyway Width. The gap of the keyway is shown with tolerances again and the semi-gap is shown. I've selected a shear strength = S s = 200 MPa, and a compressive strength = S c = 130 MPa. The information contained with ANSI/AGMA 9002-A86 did not necessarily agree with some commonly used specifications. Maximum recommended torque at continued duty 1000 RPM: 800 inch lbs. It may be mildly magnetic. For a key to function, there must be a keyway on the shaft and a keyseat on the rotating machine element. The advantage of the Js9 tolerance is that the key can be inserted and the gear manipulated without much difficulty. The main reason of failure of shaft and keyways in shaft-hub connection is the shear stress, so the focus is done on it. Shaft and hub keyway dimensions. A rounded bottom allows these keys to rock in their seat to relieve stress on the shaft caused by vibration or misalignment. 1250 0. Rounded Machine Keys. ANSI/AGMA 9002-A86 was based upon the design criteria related to bores and keyways in coupling hubs that had evolved over many years of successful industry.