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FRAME STRUCTURES
13 - 11
SERVICE PROCEDURES
INDEX
Page
General Information
11
GENERAL INFORMATION
Frames w h i c h are bent o r t w i s t e d can be s t r a i g h t -
ened, i f necessary, b y heat application. T h e tempera-
t u r e is t o be kept under 1050°F (a d u l l r e d glow) as
excessive heat w i l l i m p a i r t h e strength o f the mate-
r i a l , r e s u l t i n g i n a weakened frame.
This heat method i s permissible o n L i g h t a n d M e -
d i u m d u t y frames only. Damaged frame r a i l s , cross-
members
a n d brackets
c a n be
repaired
b y
s t r a i g h t e n i n g or replacing.
Welded connections between r a i l s a n d crossmem-
bers are n o t recommended.
STRAIGHTENING
S t r a i g h t e n i n g should be l i m i t e d t o parts n o t se-
verely damaged. N e w bolts or rivets for a t t a c h i n g the
parts should be o f same specifications as o r i g i n a l
bolts or rivets.
REPLACEMENT
Replacement is recommended as the o r i g i n a l shape
of the p a r t m a y not be easily recognizable. Also, i m -
properly straightened frame components w i l l
have
h a r m f u l effects on al i gn men t .
REPAIRING
DRILLING
No holes should be d r i l l e d i n siderail flanges as
t h i s w i l l reduce frame s t r e n g t h . Holes d r i l l e d i n
siderail v e r t i c a l web m u s t be 1-1/2 inches m i n i m u m
from top and bottom
flanges.
New holes should be located a distance away f r o m
existing holes, as n o t to reduce cross section o f
siderails i n a n y one v e r t i c a l section b y more t h a n
30%.
Page
Repairing
11
WELDING
W e l d i n g o f siderails a n d crossmembers should be
done, preferably, w i t h electric welding equipment as
i t retains heat i n a s m a l l area l i m i t i n g the change- of
hardness o f m e t a l .
A damaged frame member is to be closely inspected
for cracks. I t is possible t h a t cracks w i l l appear as a
result o f s t r a i g h t e n i n g o f a member. I n either case,
crack or cracks are t o be repaired as follows:
(1) Stop-drill a t t h e end p o i n t of the crack w i t h 1/8
inch d r i l l .
(2) V-groove crack t o allow good weld penetration.
(3) Weld u p t h e crack.
(4) G r i n d surface smooth i f reinforcement is to be
used.
USE OF
FASTENERS
Bolts or rivets can be used i n r e p a i r i n g frames or
adding reinforcement. W h e n i t is more practical t o
substitute a bolt for a r i v e t , use next larger size bolt
to prevent bolt from w o r k i n g loose. Ream holes i f
necessary.
Coned washers a r e preferred to split lock type.
Generally Grade 5 bolts w i l l suffice i n repair w o r k .
Grade 3 bolts should be avoided. Proper torque i s
mandatory to provide adequate locking and preclude
loosening o f fasteners. Refer to t h e Specifications
chart for bolt grades a n d torques.
REINFORCING
Reinforcement can be made from channel, angle or
flat stock of common carbon steel and approximately
equal i n thickness t o t h e p a r t to be repaired. I t is not
possible to recommend proper reinforcement for a l l
repairs. A reinforcement should provide a n adequate
section i n cracked area a n d have sufficient overlap
w i t h t h e o r i g i n a l p a r t and be properly attached.
Reinforcing channel should have
flanges
shorter
t h a n sidemember flanges t o preclude welding along
edge of r a i l flange. Otherwise, l o n g i t u d i n a l welds are
quite acceptable. Complete transverse welds are to be
avoided.
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