K-2 Stock Timing Pulleys STOCK TIMING PULLEYS 1/5 " - 7/8 " PITCH QD — TAPER BUSHED AND STOCK BORE Stock Bore QD Taper Bushed PITCH PULLEY IN. DESIGNATION 1 ⁄ 5" XL (Extra Light) 3 ⁄ 8" L (Light) 1 ⁄ 2" H (Heavy) 7 ⁄ 8" XH (Extra Heavy) Martin Timing Pulleys are manufactured to extremely close specifications and are stocked in minimum plain bore, Taper Bushed and Q.D. bushed styles depending on size and pitch. See tables for stock pulley types. Bushings are priced separately and must be added to pulley price. Illustrations below indicate stock pulley construction type listed in tables. Type DF Type D E F H M L Type CF Type C E L M F Type KF E L M F Type A E F M K L Type G E F L K M Type H E L K M F Type J “F” designation in pulley type means pulley is flanged. When drive center distance is eight times the diameter of the smaller pulley or when drive is operating on vertical shafts, both pulleys should be flanged. DEFINITION OF CATALOG NUMBERS EX: TB 20L100 TB — Requires Taper Bushing 20 — Number of Teeth L — 3 ⁄ 8" Pitch (Light) 100 — Belt Width 1" EX: 72L100SD 72 — Number of Teeth L — 3 ⁄ 8" Pitch (Light) 100 — Belt Width 1" SD — Requires QD Bushing EX: 16L100 Min. Plain Bore Pulley sizes shown stocked as stock bore only: max. bore listed is without keyway. If keyway is used reduce max. bore by twice keyway depth. Pulley Style Designation As Shown in Tables Dash 1 = Block Body Style Dash 2 = Web Style Dash 3 = Arm/Spoke Style Size XXH (1 1 ⁄ 4" Pitch). Available as made-to-order. Call your nearest Martin facility. Let us quote your made-to-order and large quantity requirements. Type AF
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Martin Timing Pulleys are manufactured to extremely close specifications andare stocked in minimum plain bore, Taper Bushed and Q.D. bushed stylesdepending on size and pitch.
See tables for stock pulley types. Bushings are priced separately and must beadded to pulley price.
Illustrations below indicate stock pulley construction type listed in tables.
Type DF
Type D
E F
H
ML
Type CF
Type C
E L MF
Type KF
E L MF
Type A
E FM
KL
Type G
E F
LK
MType H
E L
K
MF
Type J
“F” designation in pulley type means pulley is flanged. When drive center distance is eight times the diameter of the smaller pulleyor when drive is operating on vertical shafts, both pulleys should be flanged.
DEFINITION OF CATALOG NUMBERSEX: TB 20L100
TB — Requires Taper Bushing 20 — Number of Teeth L — 3⁄8" Pitch (Light) 100 — Belt Width 1"EX: 72L100SD
72 — Number of Teeth L — 3⁄8" Pitch (Light) 100 — Belt Width 1" SD — Requires QD BushingEX: 16L100
Min. Plain Bore
Pulley sizes shown stocked as stock bore only: max. bore listed is withoutkeyway. If keyway is used reduce max. bore by twice keyway depth.
Pulley Style DesignationAs Shown in Tables
Dash 1 = Block Body StyleDash 2 = Web StyleDash 3 = Arm/Spoke Style
Size XXH (11⁄4" Pitch).Available as made-to-order.Call your nearest Martin facility.
Let us quote your made-to-order and largequantity requirements.
Type AF
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Timing Pulley Terminology
Timing belts and pulleys — in order to handle a wide rangeof loads, speeds and applications at highest possibleefficiencies — are made in five stock pitches. Circular pitch(usually referred to as pitch) is a basic consideration in theselection of timing pulleys as with gear and chain drives.Pitch is the distance between groove centers and ismeasured on the pulley pitch circle. On the belt, pitch is thedistance between tooth centers and is measured on thepitch line of the belt.
The pitch line of the belt is located within the tensionmember and coincides with the pitch circle of the pulleymating with it. Any timing belt must be run with pulleys of thesame pitch. A belt of one pitch cannot be used successfullywith pulleys of a different pitch.
TIMING BELTTERMINOLOGY
TIMING PULLEYTERMINOLOGY
L Circular Pitch of GrooveM Minimum Depth of Groove, Including ClearanceN Width of Groove at Minimum Depth, IncludingClearance
O Pressure AngleP Top Radius of GrooveR Pitch Diameter (Always > S)S Outside Diameter
A Pitch of TeethB Depth of TeethC Width at Bottom of TeethD Pressure AngleE Radius at Bottom of TeethF Radius at Top of TeethG Pitch Line DifferentialBelt P.L. = “A” X Total No. of Teeth in Belt
C
A
F
E
D
BG
L R
L
L
S
L
P
ON
L
M
pitch(circular pitch)
Belt PitchLine
Belt Tooth
Pulley Groove
pitch line differential
pitchdiameter
outside
diameter
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Timing PulleyTerminology
Timing Pulleys
Timing pulleys have evenly spaced axial grooves cut in theirperiphery to make correct, positive engagement with themating teeth of the belt. These pulleys are designed so thatthe teeth of the belt enter and leave the grooves withnegligible friction. All pulleys, stock and made-to-order, haveminimum tooth-to-groove clearance (backlash). The pulley’spitch diameter will always be greater than its outsidediameter. Pulleys are available in a wide range of stockwidths and diameters.
Pulley Diameters
Stock timing belts should not be used over pulley diametersless than those recommended above without expectingsome reduction in belt life. This reduced belt life is the resultof flex fatigue of the steel tension members in the belt. Ifpulleys smaller than recommended must be used, the use ofspecial timing belts should be considered.
Flanged Pulleys
Because timing belts have an inherent, gentle side thrust, itis necessary to use at least one flanged pulley to preventthe belt from riding off. Generally, for economy, the smallerpulley in each drive is flanged. However, when the centerdistance is greater than eight times the diameter of thesmaller pulley on drive ratios less than 3 to 1, or when thedrive is operated on other than horizontal shafts — bothpulleys should be flanged. When a drive has three pulleys,at least two should be flanged. If the drive has more thanthree pulleys, every other pulley should be flanged.
Note: XL Pulleys stocked min. plain bore with 2 setscrews @ 90˚. If keyway is used, reduce max. bore by twice keyway depth.Pulley O.D. = P.D. – .02".
Type AF
Type A
Type DF
Type D
Type E
Type EF
Type GF
Type G
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L Stock Timing3⁄8" Pitch Pulleys
L - 3⁄8"PitchL050 For Belts 1⁄2"Wide Minimum Plain Bore F = 3⁄4 No. Part Pitch Max Bore Dimensions
Teeth Number Diameter FL O.D. Type Stk. Max. E H L Wt.
L Pulleys 10 - 16 teeth min. plain bore stocked with 1 set screw. If keyway is used, reduced max. bore by twice keyway depth.Dimensions in inches. Weight in poundsPulley O.D. = P.D. – .03"
L - 3⁄8"PitchL050 For Belts 1⁄2"Wide (3⁄8" Pitch) QD Type F = 3⁄4 No. Part Pitch Max Bore Dimensions Wt. Less Teeth Number Diameter FL O.D. Type Bush Range E K L M Bush.
Dimensions in inches. Weight in poundsPulley O.D. = P.D. – .03"*Reverse mount drilled only+Bushing Projects 1⁄16 on Small End.
L - 3⁄8"PitchL050 For Belts 1⁄2"Wide (3⁄8" Pitch) Taper Bushed Type F = 3⁄4 No. Part Pitch Max Bore Dimensions Wt. Less Teeth Number Diameter FL O.D. Type Bush Range E H L M Bush.
Dimensions in inches. Weight in poundsPulley O.D. = P.D. – .03"
L - 3⁄8"PitchL075 For Belts 3⁄4"Wide (3⁄8" Pitch) Minimum Plain Bore F = 1 No. Part Pitch Max Bore Dimensions
Teeth Number Diameter FL O.D. Type Stk. Max. E H L Wt.
Dimensions in inches. Weight in pounds.Pulley O.D. = P.D. – .03"L Pulleys 12 - 16 teeth min. plain bore stocked with 1-SS. If keyway is used, reduce max. bore by twice keyway depth.
L - 3⁄8"PitchL075 For Belts 3⁄4"Wide (3⁄8" Pitch) QD Type F = 1 No. Part Pitch Max Bore Dimensions Wt. Less Teeth Number Diameter FL O.D. Type Bush Range E K L M Bush.
Dimensions in inches. Weight in poundsPulley O.D. = P.D. – .03"*Reverse mount only
L - 3⁄8"PitchL075 For Belts 3⁄4"Wide (3⁄8" Pitch) Taper Bushed Type F = 1 No. Part Pitch Max Bore Dimensions Wt. Less Teeth Number Diameter FL O.D. Type Bush Range E H L M Bush.
Dimensions in inches. Weight in poundsPulley O.D. = P.D. – .03"
L - 3⁄8"PitchL100 For Belts 1"Wide (3⁄8" Pitch) Minimum Plain Bore F = 11⁄4 No. Part Pitch Max Bore Dimensions
Teeth Number Diameter FL O.D. Type Stk. Max. E H L Wt.
Dimensions in inches. Weight in poundsPulley O.D. = P.D. – .03"L Pulleys 14 - 16 teeth min. plain bore stocked with 1-S.S. If keyway is used, reduce max. bore by twice keyway depth.
L - 3⁄8"PitchL100 For Belts 1"Wide (3⁄8" Pitch) QD Type F = 11⁄4 No. Part Pitch Max Bore Dimensions Wt. Less Teeth Number Diameter FL O.D. Type Bush Range E K L M Bush.
Dimensions in inches. Weight in poundsPulley O.D. = P.D. – .03"*Reverse mount only
L - 3⁄8"PitchL100 For Belts 1"Wide (3⁄8" Pitch) Taper Bushed Type F = 11⁄4 No. Part Pitch Max Bore Dimensions Wt. Less Teeth Number Diameter FL.O.D. Type Bush Range E K L M Bush.
Dimensions in inches. Weight in poundsPulley O.D. = P.D. – .03"
H — 1⁄2" PitchH100 For Belts 3⁄4" and 1"Wide (1⁄2" Pitch) QD Type F = 15⁄16 No. Part Pitch Max Bore Dimensions Wt. Less Teeth Number Diameter FL. O.D. Type Bush Range E H K L M Bush.
Dimensions in inches. Weight in poundsPulley O.D. = P.D. – .054"*Reverse mount only
H — 1⁄2" PitchH100 For Belts 3⁄4" and 1"Wide (1⁄2" Pitch) Taper Bushed Type F = 15⁄16 No. Part Pitch Max Bore Dimensions Wt. Less Teeth Number Diameter FL. O.D. Type Bush Range E H L M Bush.
Dimensions in inches. Weight in poundsPulley O.D. = P.D. – .054"
H — 1⁄2" PitchH150 For Belts 11⁄2"Wide (1⁄2" Pitch) QD Type F = 113⁄16 No. Part Pitch Max Bore Dimensions Wt. Less Teeth Number Diameter FL O.D. Type Bush. Range E K L M Bush.
Dimensions in inches. Weight in poundsPulley O.D. = P.D. – .054"*Reverse mount only
H — 1⁄2" PitchH150 For Belts 11⁄2" Wide (1⁄2" Pitch) Taper Bushed Type F = 113⁄16 No. Part Pitch Max Bore Dimensions Wt. Less Teeth Number Diameter FL O.D. Type Bush Range E H K L M Bush.
Dimensions in inches. Weight in poundsPulley O.D. = P.D. – .054"
H — 1⁄2" PitchH200 For Belts 2"Wide (1⁄2" Pitch) QD Type F = 2-11⁄32 No. Part Pitch Max. Bore Dimensions Wt. Less Teeth Number Diameter FL. O.D. Type Bush Range E K L M Bush.
Dimensions in inches. Weight in poundsPulley O.D. = P.D. – .054"*Reverse mount only
H — 1⁄2" PitchH200 For Belts 2"Wide (1⁄2" Pitch) Taper Bushed Type F = 211⁄32 No. Part Pitch Max. Bore Dimensions Wt. Less Teeth Number Diameter FL. O.D. Type Bush Range E L M Bush.
Dimensions in inches. Weight in poundsPulley O.D. = P.D. – .054"
H - 1⁄2"PitchH300 For Belts 3" Wide (1⁄2" Pitch) Minimum Plain Bore F = 3-3⁄8
Dimensions in inches. Weight in poundsPulley O.D. = P.D. – .054"
H - 1⁄2"PitchH300 For Belts 3" Wide (1⁄2" Pitch) QD Type F = 3-3⁄8 No. Part Pitch Max. Bore Dimensions Wt. Less Teeth Number Diameter FL. O.D. Type Bush Range E K L M Bush.
Dimensions in inches. Weight in poundsPulley O.D. = P.D. – .054"*Reverse mount only
H - 1⁄2"PitchH300 For Belts 3" Wide (1⁄2" Pitch) Taper Bushed Type F = 3-3⁄8 No. Part Pitch Max. Bore Dimensions Wt. Less Teeth Number Diameter FL. O.D. Type Bush Range E L M Bush.
Dimensions in inches. Weight in poundsPulley O.D. = P.D. – .054"
XH — 7⁄8 PitchXH200 For Belts 2" Wide (7⁄8" Pitch) Taper Bushed Type F = 29⁄16 No. Part Pitch Max. Bore Dimensions Wt. Less Teeth Number Diameter FL O.D. Type Bush Range E H L M Bush.
Dimensions in inches. Weight in poundsPulley O.D. = P.D. – .11"