Shaft Coupling

Coupling is a core component that transmits power and motion
from the driving shaft to the driven part while absorbing misalignment
and any possible factors that could reduce efficiency of machines
(e.g. vibration, noise, electric current, etc.)

Customer-friendly Services

Keyway on Coupling Hubs

Shaft(Bore) Diameter Keyway Dimension Nominal Size
Ød1/ Ød2 b(mm) t(mm) (b x h)
Over ~ To Mark No Mark H J Size Tolerance
Size Tolerance(E9) Tolerance(H9) Tolerance(Js9)
Ø6(over) ~ Ø8 2 +0.039
+0.014		 +0.025
0		 ±0.0125 1 +0.1
0		 2 x 2
Ø8 ~ Ø10 3 1.4 3 x 3
Ø10 ~ Ø12 4 +0.05
+0.02		 +0.03
0 		±0.015 1.8 4 x 4
Ø12 ~ Ø17 5 2.3 5 x 5
Ø17 ~ Ø22 6 2.8 6 x 6
Ø22 ~ Ø30 8 +0.061
+0.025		 +0.036
0		 ±0.018 3.3 8 x 7
Ø30 ~ Ø38 10 +0.2
0		 10 x 8
Ø38 ~ Ø44 12 +0.075
+0.032		 +0.043
0		 ±0.0215 12 x 8
Ø44 ~ Ø50 14 3.8 14 x 9
Ø50 ~ Ø58 16 4.3 16 x 10
Ø58 ~ Ø65 18 4.4 18 x 11
Ø65 ~ Ø75 20 +0.092
+0.04		 +0.052
0		 ±0.026 4.9 20 x 12
Ø75 ~ Ø85 22 5.4 22 x 14
  • The location of keyway on a coupling hub is determined by the standard product design of Sung-il Machinery. If you need a keyway in a different location, please discuss with our Customer Support team in advance.
  • The standard keyway tolerance is E9, which is the most suitable option in terms of the assembly convenience.
  • If a specific keyway tolerance is required for a special case, please choose the code from the table and mention it on the PO. (Please refer to “How to order” below)
  • Keyways can be applied on the following clamping methods of couplings.
※ exception 1: SFC series – Structurally impossible to have keyway
※ exception 2: SAD series – Due to structural interference (increased number of assembly holes), we ask you to check with our customer support team for availability in advance.

※ HOW TO ORDER

  • Please indicate K(b=width) next to ID(d1)
  • In general, t(depth) of a keyway is automatically determined by b(width). However if a keyway with special dimension is required, please discuss with our Customer Support team in advance. (For example, K3 will be provided with b(3mm) & t(1.4mm) unless there is a special remark.)
  • Keyway Tolerance
    Mark No Mark H J
    Tolerance E9 H9 Js9

Non-standard Inner Diameter (ID) Available

Case 1 : Non-standard Inner Diameter(ID) Re-boring : Between standard min. ID and standard max. ID
Model Standard Inner Diameter (d1, d2) (mm)
10 11 12 12.7 14 15 15.875 16 17 18 19 20 22 24 25 26 28 30 32 35 40 45 50
SDCS-54C ● ● ● ● ● ● ● ● ● ● ● ● ● ● ●
SDCS-64C ● ● ● ● ● ● ● ● ● ● ● ● ● ●★ ●★ ●★ ●★
SDS-80C ● ● ● ● ● ● ● ● ● ● ● ● ● ● ●
  • Any Integer Inner Diameter(ID) between standard min. ID and standard max. ID could be provided even they are not indicated on the standard ID table.
    (※ Exception Item: SDS-12C, SDWA-12C, SOH-6, SOH-8, SOH-10, SOH-12, SRB-8, all sizes of SFC)
  • For example, ID:Ø27 on SDCS-64C is available as Ø27 is within the range between Ø12(min.) and Ø32(max.)
Case 2 : Non-standard Inner Diameter(ID) Re-boring : Smaller than standard min.ID and bigger than standard max.ID
  • We Sung-il team will always try our best to supply goods at the customer’s best convenience. Please firstly ask our Customer Support team to check whether it is structurally possible.
  • In the case of non-standard ID bigger than max.ID, please be aware that durability would get decreased from the ordinary performance of coupling.
Case 3 : Special tolerance for Inner Diameter
  • Please ask our Customer Support team to check if you require a special(customized) bore tolerance for coupling.

Additional Tapped-holes Parts

  • Sung-il Machinery provides additional tapped holes on coupling hubs upon the request.
  • This additional tapped holes are usually requested when there are keyway used on a coupling.
  • For this service, please contact Sung-il Customer Service team prior to firm order placement, in order to discuss accurate location of the tapped hole and the screw thread.

Parts with Alternative Material Options

  • Sung-il Machinery provides alternative material options for Coupling parts.
    (FAS screws: to fasten a shaft into a coupling & ASS screws: to assemble a coupling itself)
    1) Stainless Steel (STS304)
    2) SCM435 with surface treatment -Electroless Nickel Plating
  • Caution: Slip torque would become lower if the body material or surface treatment of screws are changed from the standard (SCM435, Black Oxide) version.
Case 1 : Stainless Steel

  • Standard : SCM435 (Black Oxide)
  • Option(1) : STS304 (Stainless Steel)
Case 2 : Surface treatment – Electroless Nickel Plating

  • Standard : SCM435 (Black Oxide)
  • Option(2) : SCM435
    (with surface treatment -Electroless Nickel Plating)

※ Standard Product Models with the Parts made of Stainless Steel or Electroless Nickel Plating

Model Size (OD) Body Material Surface Treatment Screws
SRBS All Sizes Stainless Steel – STS304
SRBMS All Sizes Stainless Steel – STS304
SDSS All Sizes Stainless Steel Electropolishing STS304
SDWS All Sizes Stainless Steel Electropolishing STS304
SHDS-NI 126, 144 Steel Electroless Nickel Plating SCM435 (Electroless Nickel Plating)
SHDW-NI 126, 144 Steel Electroless Nickel Plating SCM435 (Electroless Nickel Plating)
SJC 120, 135, 160 Steel Electroless Nickel Plating SCM435 (Electroless Nickel Plating)
SOHMP All Sizes High Strength Aluminum Alloy – STS304
SOHSV All Sizes Stainless Steel Electropolishing STS304
SRGS All Sizes Stainless Steel – STS304

Side-clamp Hub Split Option

  • Side-clamp Hub Split Option is available for certain sizes
  • Please refer to the below table to check the coupling types which this option is available, and you can refer to “HOW TO ORDER” and “Dimensions / Performance” tables for more specific information.
Coupling types
SHR SD SAD SHD SCD SJC SOH SRB SRG SCJ SFC
High performance Rubber Disk Advanced Disk High Torque Disk Concentricity Disk Jaw Oldham Radial Beam Rigid Cross Joint Urethane Flexible
O △ X O X △ △ X O X X

※ △ symbol in the above table means that the availability is subject to differ according to each outer diameter size.