Observe the following precautions in drilling holes (Fig. 22):
1) Do not notch the upper and lower flanges of the side rail, gusset, and
crossmember.
2) Do not drill holes in crossmembers.
3) Do not drill holes in the upper and lower flanges of the side rails ex-
cept, (a) holes to install the end crossmember and (b) holes near the
frame end to install bolts to reduce fore-and-aft movement of the sub-
frame.
4) Do not drill holes in the upper and lower portions of the side rail web.
No part of the holes is to be within 18% of the frame height (20% in the
case of 539 MPa {55 kgf/mm
2
, 78210 psi} tensile steel).
5) Holes must not be drilled within 3.15 in (80 mm) of the perpendicular
bending lines of the side member.
6) The maximum hole diameter should be as follows:
7) The pitch between two hole centers should be at least 2.17 in (55 mm)
or 4.5 times the diameter of the larger hole, whichever is greater. This
rule should also be applied to the pitch between a new and the exist
-
ing hole.
8) The edge of the holes should be more than 1.18 in (30 mm) from any
weld.
9) No more than three holes in a series should be drilled in a vertical line.
If three holes are required in a vertical line, the diameter should be
0.43 in (11 mm) or less for UD1800, UD2000, UD2300, UD2600 and
UD3300. Avoid series of holes in a horizontal line whenever possible.
10) Drill all holes perpendicular to the face to be drilled.
11) When drilling a hole in the gusset for U-bolt sub-frame mounting, the
hole diameter should be 0.79 in (20 mm) or less and the distance
from the edges should be more than 1.18 in (30 mm).
12) Drill the holes as far as possible from existing holes in the flange,
welds and the end portion of the gusset.
Max. diameter Chassis model
0.51 in (13 mm) UD1800, UD2000, UD2300, UD2600, UD3300
C17
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