Description
M108 105mm Self-Propelled Howitzer Equilibrator Spring – P/N G10913284
Item Overview
This M108 105mm self-propelled howitzer equilibrator spring is a large torsion spring from the gun-mount system. It counterbalanced the weight of the cannon and helped the crew raise or lower it with the manual elevation controls. This is not a vehicle suspension spring or part of the gun’s recoil system. It is a mechanical component intended for collecting, restoration, study, or display.
Identification and Features
The identification tag connects this spring to the M108 howitzer and a 1968 U.S. Army contract. The Federal Stock Number belongs to Federal Supply Class 1015, which covers gun components for weapons from 75mm through 125mm. The initials “A.S.F.” likely identify American Steel Foundries, but that manufacturer expansion has not been independently confirmed.
- Item: Equilibrator torsion spring
- Primary application: M108 105mm self-propelled howitzer
- Associated cannon: 105mm Howitzer M103
- Associated mount: M139
- Part number: G10913284
- Federal Stock Number: 1015-886-5884
- Federal Supply Class: 1015—guns and gun components from 75mm through 125mm
- Contract number: DAAF01-68-C-0511
- Contract year: 1968
- Manufacturer marking: A.S.F.; likely American Steel Foundries
Original Service Function
The M108’s 105mm cannon and mount placed a large amount of weight ahead of their pivot point. The equilibrator spring stored torsional force that helped balance this weight as the gun moved through its elevation range. This reduced the force needed at the elevation handwheel and allowed the crew to aim the howitzer more smoothly. The spring did not absorb the force of firing because the cannon’s recoil mechanism performed that job. It also did not support the vehicle’s road wheels, which used a separate torsion-bar suspension system.
M108 Weapon-System Application
The M108 mounted the 105mm M103 howitzer in the M139 mount inside a fully rotating turret. The weapon could be traversed through 360 degrees and elevated from approximately 6 degrees below level to 75 degrees above level. Manual handwheels allowed the crew to control direction and elevation, making the equilibrator an important part of the aiming system. The M108 shared major chassis and turret features with the 155mm M109, but this tagged spring is identified with the M108 system and should not be represented as interchangeable with M109 parts without additional documentation.
Historical Background
The U.S. Army developed the M108 during the late 1950s and early 1960s as a mobile 105mm artillery system that could travel with armored and mechanized units. The first vehicles were accepted in 1962, and approximately 355 were produced for the United States. Cadillac Motor Car Division of General Motors manufactured the vehicle. Its enclosed turret protected the five-person crew while providing mobile indirect-fire support. The closely related M109 carried a larger 155mm howitzer and eventually became the more widely used member of the vehicle family.
History of Use
U.S. Army artillery units operated the M108 during the Vietnam War, where its tracked chassis allowed it to move between fire bases and support positions. M108 batteries supplied 105mm artillery fire in support of infantry and other ground forces. The howitzer was later removed from regular U.S. service as the Army placed greater emphasis on the 155mm M109, but M108 vehicles continued serving with several allied countries. The 1968 contract marking on this spring fits the period when the Army was maintaining M108 vehicles and procuring replacement parts for the fleet.
Condition
This is a military-surplus mechanical component. It may show scratches, paint loss, oxidation, surface rust, grease, dirt, worn markings, storage wear, or other signs of age and previous handling. The spring has not been represented as inspected, tested, or certified for installation in an operational weapon system. This listing includes one equilibrator spring only; the howitzer, gun mount, attachment hardware, pivots, and other components are not included unless specifically stated. Please check the pictures for the general condition of the item.
Ideal For
This large M108 equilibrator spring is a specialized artifact for collections and restoration projects focused on American self-propelled artillery, Vietnam War equipment, and historic armored vehicles.
- M108 howitzer restoration projects
- Vietnam War artillery displays
- Military museums and educational exhibits
- Self-propelled howitzer collections
- Historic armored-vehicle collections
- Military engineering and mechanical displays
Approx length 42", Approx width 10", Approx height 10", Approx weight 62lbs.
Pictures are stock images of our inventory. Unless otherwise noted, you will not be receiving the exact item shown in the pictures. The pictures are representative of the item’s general condition. The item you receive might be slightly better, or worse, condition than was shown in the pictures.
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