TM 55-203
(1)
Shims must be cut to proper size 1
e.
In all cases, the entire crack should be cut
5/16 by 5 by 5 1/2 inches.
out far enough back so that no portion of the crack
remains in the metal, and the surfaces where new metal
(2)
Shims will be drilled In pairs to match
is to be deposited are clean and reasonably smooth.
holes in related coupler butts.
f.
If a gas pocket encountered when cutting
(3)
Coupler butts will be ground to give
out a crack or making a weld cannot be entirely
neat seating of shims.
removed, the part must not be reclaimed.
(4)
Shims will be beveled 3/8 of an inch
g.
On couplers, welds must be dressed off, so
to 60angle (or J-weld preparations given) for all around
that there is no projection on the front face, inside the
contact face. No beveling of the coupler butt is
guard arm, or at the bottom of the shank. Also, no
permitted.
projections or beads which might interfere with operation
of the coupler will be allowed inside the knuckle or lock
(5)
Shims will be tightened to welding
cavities.
position on the coupler butt by dummy pin and key, and
care will be exercised to see that shim edges are flush
h.
On yokes, welds must be dressed off flush
with corresponding edges of the coupler butt.
with parent metal on the inside and outside of ,straps
(6)
After shims are in position, they will
and in the key slots. Front end of key slots must be
be welded to the coupler butt by the shielded arc electric
gaged from rear bearing surface of yoke to insure equal
method.
lengths on each side of the yoke so that it will line up
properly in assembly. After welding, couplers and cast
(7)
All sharp corners of applied shims
steel yokes must be normalized.
No welding is
must be removed by grinding.
permitted on forged steel coupler yokes.
20-8. Cast Steel Yokes
20-7. Welding Coupler Cracks
a.
Cracks in straps not closer than 3 inches to
a.
Transverse cracks, including shrinkage
junction with the rear of the yoke may be welded
cracks in the shank of the coupler from the rear end of
regardless of extent or direction of the crack. If a crack
the shank to and including the backwall of the horn, may
stands open, a means must be used to hold the severed
be welded There is no limitation in length or depth of
ends alined in proper relation while welding, so that the
cracks that may be welded.
length of the crack is not changed.
b.
Cracks in the guard arm and the front face
b.
Cracks anywhere in the front section of the
of the coupler, including cracks extending the full length
yoke, including the key slot, may be welded.
of the face into the lock opening and into top and bottom
parts of the wall, may be welded. If a crack is more than
c.
Cracks in the rear end of yokes, including 3
1/16 inch wide, parts should be pressed back to original
inches of adjacent strap, must not be welded.
contour before welding is done.
c.
A coupler having a 5- by 7-inch shank with a
6 1/2-inch butt may be converted to one with a 9 1/8-
inch butt by welding metal shims on the top and bottom
of the butts in accordance with the following regulations:
20-5
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