All Military Specification (Mil-Spec) pulleys are manufactured to MIL-DTL-7034. When selecting the proper Mil-Spec Pulley, there are four variations to consider: MIL-DTL-7034/1, MIL-DTL-7034/2, MIL-DTL-7034/3 & MIL-DTL-7034/4. All four callouts have unique features in terms of outer diameter (OD), cable compatibility, allowable loads, and bore size. At eSheaves, we want to help our customers understand the specific differences between the Mil-Spec Pulley choices to ensure they buy the right product for their aircraft cable system. Below are the key differences between the four Mil-Spec Pulley categories.
MIL-DTL-7034/1– Cross-Reference MS20219 (superseded AN219) is a pulley product used for secondary control in Aircraft. MIL-DTL-7034/1 pulleys:
Have two options for bore diameter depending on OD, 0.250 inches or 0.625 inches. A pulley's bore diameter is also known as the center hole or inside diameter
Come in a range of OD's from 1.312" up to 2.625"
Have an allowable load of 480 lbs
Fit cables that are either 1/16" or 5/32"
MIL-DTL-7034/2– Cross-Reference MS20220 (superseded AN220) are pulleys used for flight control in Aircraft. MIL-DTL-7034/2 pulley specs:
All have a bore diameter of 0.3125"
Vary in OD from 1.750" up to 5.500"
Depending on the choice of OD, have an allowable load from 500 lbs (with 1.750" OD) to 2500 lbs (with 5.500" OD)
Fit cables that are 1/8″, 5/32″, or 3/16″
MIL-DTL-7034/3– Cross-Reference MS20221: are heavy-duty pulleys used for secondary control in Aircraft. MIL-DTL-7034/3 pulleys feature:
Two options for bore diameter depending on OD, 0.3125" or 0.500"
A range in OD from 2.625" to 5.625"
Variations in allowable load. With the smallest OD, a MIL-DTL-7034/3 pulley allows 2500 lbs, and with the largest OD can hold 7000 lbs
The ability to fit cable sizes 3/16″, 7/32″, or 1/4″
MIL-DTL-7034/4– Cross-Reference MS24566 (superseded AN210B) are anti-friction bearing pulleys used for control In Aircraft. MIL-DTL-7034/4 pulleys have:
Three options for bore diameter, 0.190", 0.250", or 0.375" all dependent on choice of OD.
6 different OD options ranging from 1.250" to 6.000"
An allowable load up to 4000 lbs on the pulleys with the largest OD
The capacity to fit 7 different cable sizes depending on the choice of OD. MIL-DTL-7034/4 pulleys fit 1/16″, 3/32″, 1/8″, 5/32″, 3/16″, 7/32″ and, 1/4″ cables
Despite all Military Specification (Mil-Spec) pulleys being manufactured to MIL-DTL-7034, we've shown that there are four unique variations to consider when selecting the right product for your aircraft cable system.MIL-DTL-7034/1, MIL-DTL-7034/2, MIL-DTL-7034/3 & MIL-DTL-7034/4. Choosing a pulley for the proper OD, cable size, and loads is simplified by understanding the key differences between the four Mil-Spec Pulley categories.