Operation CHARM: Car repair manuals for everyone.

Procedures




Frame Drilling
1. Holes that would weaken the frame sidemember should not be drilled in the frame.
2. Holes are not to be drilled in the sidemember's top or bottom flange.
3. Holes to mount brackets, out-riggers and supports may be drilled in the vertical frame side rail web with the following restrictions:
- Material between edge of hole and inside of upper or lower flange must not be less than 38.1 mm (1.50 in) for low carbon steel (36,000 psi yield).
- The minimum edge distance between any 2 holes up to 15.74 mm (0.625 in) diameter must be 25.4 mm (1.00 in). For larger than 15.74 mm (0.625 in) diameter holes, the minimum edge distance must be 1.5 times the diameter of the largest hole.
- No holes will be allowed to exceed 19.05 mm (0.75 in) in diameter.
- Avoid close vertical succession of fasteners.
- All attaching fasteners, including flat washers, must be of high strength steel (Grade 8).