Operation CHARM: Car repair manuals for everyone.
Manuals through 2025 now available!

Our trusted friends have launched a new website named LEMON, which has newer manuals. It also contains all the CHARM manuals.

LEMON is the spiritual successor to CHARM, I recommend you try it!

Link: lemon-manuals.la
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Drilling Precautions

DRILLING PRECAUTIONS

1. Holes that would weaken the frame side member 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 1.50 inch for low carbon steel (36,000 psi yield).
- The minimum edge distance between any two holes up to 5/8-inch diameter must be 1.00 inch. For larger than 5/8-inch diameter holes, the minimum edge distance must be 1.5 times the diameter of the largest hole.
- No holes will be allowed to exceed 0.75 inch in diameter.
- Avoid close vertical succession of fasteners.
- All attaching fasteners, including flat washers, must be of high strength steel (Grade 8).