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Collisionology™

Bench 101: The basics of repair benches

Posted by Chief Automotive on Mar 29, 2017 4:45:00 PM

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A defensive lineman versus a strong safety. A sumo wrestler versus a jiu-jutsu black belt. A Peterbilt versus a Ferrari.

There are a lot of comparisons you could make between a frame rack and a collision bench. But all of those comparisons will come down to one thing: brute force versus measured, precise power.

frame rack is like having several teams of horses attached to several different points of a car’s frame. In order to straighten the frame, you send one team of horses in one direction to make a big pull. Then, you send another team of horses in another direction to make another big pull. A third team pulls in a different way. In the end, you’ve used those horses to muscle the frame back to form.

repair bench on the other hand is like having one, well-trained horse that can make big pulls if necessary—but it prefers to make smaller, more technical, pulls. This brings the car’s frame back to spec one piece at a time. You get to a complete repair by making smaller, precise repairs. 

Benches hold a car in alignment according to OEM specs in multiple targeted points with fixtures. The fixtures are used as holding, and measuring all at the same time. You position the car’s replacement parts and pieces back into alignment with the fixtures on the bench, repairing the vehicle using the same method that was used to build it in the first place. And when you need to straighten instead of replace a part, the best benches have fixtures that also have the strength to be the primary anchoring for the vehicles structure. This works by setting up multiple anchoring points on the bench that are also the reference points for structural measurements. These points then let you make small, incremental adjustments to bring the damage parts back within specs while the fixtures isolate the pulling forces away from other parts of the vehicle where they could do damage.

Repair benches have different parts that work in unison to get a vehicle back to being road-worthy:

  • The primary anchors are fixtures used to hold a vehicle for pulling, and for initial positioning of the vehicle on the bench. There are typically four primary fixtures used on a bench.
  • If a vehicle needs more precision than the primary fixtures provide, the best benches have multiple and very strong fixtures that can attach to the car giving it, six, eight- or  even twelve-point anchoring and holding.
  • Benches will also have conventional sill clamps for secondary anchoring of the rockers or sills when needed with a “big” pull.
  • Movable and locking crossbeams. These provide even more stability and precision. The best benches will have crossbeams that are adjustable in 1mm increments, offering the most in versatility.
  • Pulling tower. This provides the power to pull repairs into alignment. The best benches have towers that easily move all the way around the vehicle with little effort. Some manufacturers also provide an option for a second pulling tower to work in tandem with main tower.
  • Many benches come with an option for an integrated lift (often a scissor lift).

Full-frame holding clamps. Trucks and SUVs often require different positioning and anchoring than cars, so the best manufacturers offer optional full frame clamps for the primary anchoring of them. Additional points on the truck or SUV frame can then also be held and anchored using the same fixtures that are used for cars, providing up to 12 point anchoring of these vehicles also.

See the full line of Globaljig presented by Chief benches at ChiefAutomotive.com.

Topics: Auto Body Repair