26. (a) When automobile propeller shafts and rear axles break, it is generally adjoining the square end. Is it advisable to weld this short piece on?
(b) What is the correct procedure in a case of this kind?
27. (a) If a case-hardened ring-gear is to have its teeth built up or new ones added, how is it handled after welding?
(b) Should all case-hardened work be so treated after welding?
28. (a) In welding two pieces of metal, one of which is considerably lighter than the other, how is the flame held in order to bring both pieces to a fusion at the same time?
29. (a) If a steel weld were to break in the line of weld, how should it be prepared if it is to be rewelded?
(b) Does this procedure apply only to steel?
30. Were a hole 6 inches square in a sheet of steel to be welded up without preheating, what would be the approximate size of the patch necessary and how would it be prepared, in order to take care of the expansion and contraction strains?
LECTURE NUMBER TWELVE
Subject—Steel Welding
(Part Four)
31. (a) Why should a steel weld of any kind be executed as rapidly as possible?