(4)
Install new insert, while primer is wet, three-quarters to one and one-half turns below surface of countersink.
(5)
Remove tang, if applicable, using long-nosed pliers (SECTION VII) or blunt tool and hammer (SECTION VII).
(6)
Touch up lead thread on component by wiping on a thin coat of primer (Type I, Class C) (SECTION VII) to seal surface scratches and adjacent area around the insert hole.
(7)
Allow primer to cure four to six hours at room temperature or by baking for one hour at 180 to 275F (82 to 135C).
C. Method No. 407C: Loose or Damaged Keensert Stud Repair
Loose or damaged Keensert studs are repaired using different procedures. Step (1) described repair of a loose Keenert stud, and Step (2) describes repair of a damaged Keensert stud.
NOTE: Rotational movement of Keensert studs in component undergoing repair is not allowed. If rotational movement exists, replace stud be completing Step (2).
(1) Loose Keensert studs are repaired as follows:
(a)
Fabricate a punch of suitable material with blade width and thickness slightly smaller than keyway for stud locking key.
(b)
Using punch, drive lock keys of stud further into keyways of stud until stud is tight.
NOTE: Depth of key shall not exceed an amount equal to half the length of stud material inserted in the assembly. If stud will not tighten, replace stud by completing Step (2).
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(c)
If threads of hole for the stud are damaged, tap new threads in the hole one size larger than existing threads. Use new a stud with matching threads.
NOTE: Threads on external portion of stud shall be the same as on stud removed.
(d)
Wipe a thin even coat of primer (Type I, Class C) (SECTION VII) to the area around stud to seal the surfaces from the joint in all directions.
(e)
Allow primer to cure four to six hours at 180 to 275F (82 to 135C) prior to assembly usage.
(2) Damaged Keensert studs are repaired as follows:
(a) Cut off stud just below mounting surface to expose pilot hole for removal drill.
NOTE: Studs less than three-eighths inch diameter do not have a pilot hole.
CAUTION: DO NOT ALLOW DRILL TO TOUCH HOUSING OR DAMAGE MAY RESULT.
(b)
Using pilot hole as a guide, drill out stud until only a thin shell remains.
(c)
Bend locking keys inward and break them off.
(d)
Remove stud using an "easyout" tool.
WARNING: SOLVENT VAPORS ARE TOXIC AND FLAMMABLE. DO NOT INHALE VAPORS. OBSERVE FIRE PRECAUTIONS.
(e)
Clean hole from which stud was removed using solvent (Federal Specification P-D-680, Type I) (SECTION VII).
(f)
Apply a thin even coat of wet primer (Type I, Class C) (SECTION VII) to the threaded hole to receive the replacement stud.
NOTE: Application of primer shall be uniform and neat in appearance without bare spots or runs.
1 Blind holes shall be coated to cover adjacent walls with primer. The bottom need not be covered. Allow primer to dry two or three minutes before installing stud.
2 Through-holes in components shall be coated to cover all internal surfaces through to adjacent painted surfaces. The end of stud need not be covered.
(g)
While the primer is still soft, stud shall be turned into threaded hole until step is 0.010 to 0.030 inch (0,245 to 0,762 mm) below machined surface.
(h)
Using a punch, drive lock keys into keyways of stud until flush with step of stud.
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(i)
Wipe a thin even wet coat of primer to surfaces adjacent to the locking device of the stud to seal scratches and insulate dissimilar metal surface.
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