UNITIZED STRUCTURAL BODY REPAIR FINAL QUESTIONS
WITH SOLUTIONS GRADED A+ 2025/2026
✔✔Hole Saw - ✔✔A saw blade of annular (ring) shape, whose annular kerf creates a
hole in the work piece without having to cut up the core material.
✔✔Abrasive Wheels and Bits - ✔✔Grinds away weld nuggets. Base metal stays intact
but throws metal and sparks all over. (MESSY)
✔✔Weld Nuggets - ✔✔A weld bead.
✔✔Air Chisels - ✔✔A flat blade. Thinner metal is torn easily. Use to finish after welds
have been cut with another too.
✔✔Oxyacetylene Torches - ✔✔DO NOT use to remove welds. Use to remove parts.
Cut must be 3-4 inches from the final cut to insure that the intense heat will not affect
the steel that will remain.
✔✔Sectioning - ✔✔Separating parts at a factory joint is not always the best choice. You
may have these issues. Extensive, unnecessary disassembly, destruction of corrosion
protection, and/or Limited access to entire component. Check Manuals.
✔✔Areas to Avoid - ✔✔Crush Zones, Complex Structures, Mounting Locations, Large
Holes (in excess of 1/4)
✔✔Staggered Butt Joints - ✔✔Usually used on mild steel pillars, rails, and multi-layer
rockers.
✔✔Butt Joints with Insert - ✔✔Works well on closed sections such as rockers, pillars,
and rails. The additional layer provided by the insert has several roles, improved fit up,
replacing strength lost when welding HSS and preventing burn-through on thin sheet
metal.
✔✔Butt Joint with Overlap - ✔✔Performed much like a staggered butt joint, but the
panels overlap 1/16 to 1/4 to restore strength lost when welding HSS.
✔✔Lap Joints - ✔✔Are most often used on single layer parts such as floors, but also
may be used on mild steel pillars and rear rails.
✔✔ Unibody - ✔✔Lightweight stamped sheet metal components that are welded to
each other to create a single unit.
✔✔Space Frame - ✔✔Body panels can be made from plastic are steel. Steel may be
Mild, Intermediate, or HSS. Panels may hide damage to frame or structure.
, ✔✔Crush Zones - ✔✔Structural components such as rails are designed to collapse and
bend at specific points.
✔✔Collision Energy Management - ✔✔Goal is passenger protection. Front and rear
structures act as crush-able energy absorbers.
✔✔Direct Damage - ✔✔POI. Easily located and diagnosed.
✔✔Indirect Damage - ✔✔transmission of collision energy beyond the area of immediate
impact. Examples; Split seam sealers, pulled spot welds, misaligned panels, buckles in
steel, cracked glass, and cracked or chipped paint.
✔✔Passive Restraint Systems - ✔✔Must have service manual. No two are alike.
✔✔Datum - ✔✔Imaginary plane or line beneath the vehicle. Measures height.
✔✔Centerline - ✔✔Vertical plane that passes from the front of the vehicle to the rear.
Measures Width. May have stamped marks on vehicle body structure. Is confirmed by
referencing at last 3 width measurements in the undamaged portion of the vehicle.
✔✔Zero Planes - ✔✔Vertical plane that passes from side to side. Confirmed by
measuring 3 length measurements from the undamaged portion of the vehicle.
✔✔Symmetry - ✔✔Equal on each side of the vehicle.
✔✔Asymmetrical - ✔✔Unequal on each side of the vehicle. (spare tire well)
✔✔Reference Points - ✔✔Bolts or nuts, Holes, Mechanical attachment points, Edges of
panels, Door strikers, Corner of openings. Common tolerance is =/.3mm (1/8) or all the
way to 1mm (1.32).
✔✔Loaded Measurements - ✔✔Drivetrain In
✔✔Unloaded Measurements - ✔✔Drivetrain out
✔✔Point to Point Measurements - ✔✔shortest distance between 2 reference points.
AKA "as the crow flies". Uses tram or steel tape measure.
✔✔Datum Measurements - ✔✔Taken at Datum plane, height differences between
reference points. Laser measuring system
✔✔Computerized Measuring System - ✔✔compare data stored in a software program
or a central database. Get hard copy of measurements. Can watch while pulling.
WITH SOLUTIONS GRADED A+ 2025/2026
✔✔Hole Saw - ✔✔A saw blade of annular (ring) shape, whose annular kerf creates a
hole in the work piece without having to cut up the core material.
✔✔Abrasive Wheels and Bits - ✔✔Grinds away weld nuggets. Base metal stays intact
but throws metal and sparks all over. (MESSY)
✔✔Weld Nuggets - ✔✔A weld bead.
✔✔Air Chisels - ✔✔A flat blade. Thinner metal is torn easily. Use to finish after welds
have been cut with another too.
✔✔Oxyacetylene Torches - ✔✔DO NOT use to remove welds. Use to remove parts.
Cut must be 3-4 inches from the final cut to insure that the intense heat will not affect
the steel that will remain.
✔✔Sectioning - ✔✔Separating parts at a factory joint is not always the best choice. You
may have these issues. Extensive, unnecessary disassembly, destruction of corrosion
protection, and/or Limited access to entire component. Check Manuals.
✔✔Areas to Avoid - ✔✔Crush Zones, Complex Structures, Mounting Locations, Large
Holes (in excess of 1/4)
✔✔Staggered Butt Joints - ✔✔Usually used on mild steel pillars, rails, and multi-layer
rockers.
✔✔Butt Joints with Insert - ✔✔Works well on closed sections such as rockers, pillars,
and rails. The additional layer provided by the insert has several roles, improved fit up,
replacing strength lost when welding HSS and preventing burn-through on thin sheet
metal.
✔✔Butt Joint with Overlap - ✔✔Performed much like a staggered butt joint, but the
panels overlap 1/16 to 1/4 to restore strength lost when welding HSS.
✔✔Lap Joints - ✔✔Are most often used on single layer parts such as floors, but also
may be used on mild steel pillars and rear rails.
✔✔ Unibody - ✔✔Lightweight stamped sheet metal components that are welded to
each other to create a single unit.
✔✔Space Frame - ✔✔Body panels can be made from plastic are steel. Steel may be
Mild, Intermediate, or HSS. Panels may hide damage to frame or structure.
, ✔✔Crush Zones - ✔✔Structural components such as rails are designed to collapse and
bend at specific points.
✔✔Collision Energy Management - ✔✔Goal is passenger protection. Front and rear
structures act as crush-able energy absorbers.
✔✔Direct Damage - ✔✔POI. Easily located and diagnosed.
✔✔Indirect Damage - ✔✔transmission of collision energy beyond the area of immediate
impact. Examples; Split seam sealers, pulled spot welds, misaligned panels, buckles in
steel, cracked glass, and cracked or chipped paint.
✔✔Passive Restraint Systems - ✔✔Must have service manual. No two are alike.
✔✔Datum - ✔✔Imaginary plane or line beneath the vehicle. Measures height.
✔✔Centerline - ✔✔Vertical plane that passes from the front of the vehicle to the rear.
Measures Width. May have stamped marks on vehicle body structure. Is confirmed by
referencing at last 3 width measurements in the undamaged portion of the vehicle.
✔✔Zero Planes - ✔✔Vertical plane that passes from side to side. Confirmed by
measuring 3 length measurements from the undamaged portion of the vehicle.
✔✔Symmetry - ✔✔Equal on each side of the vehicle.
✔✔Asymmetrical - ✔✔Unequal on each side of the vehicle. (spare tire well)
✔✔Reference Points - ✔✔Bolts or nuts, Holes, Mechanical attachment points, Edges of
panels, Door strikers, Corner of openings. Common tolerance is =/.3mm (1/8) or all the
way to 1mm (1.32).
✔✔Loaded Measurements - ✔✔Drivetrain In
✔✔Unloaded Measurements - ✔✔Drivetrain out
✔✔Point to Point Measurements - ✔✔shortest distance between 2 reference points.
AKA "as the crow flies". Uses tram or steel tape measure.
✔✔Datum Measurements - ✔✔Taken at Datum plane, height differences between
reference points. Laser measuring system
✔✔Computerized Measuring System - ✔✔compare data stored in a software program
or a central database. Get hard copy of measurements. Can watch while pulling.
