The Blacksmith's Craft
PART III
Having completed the first twelve lessons the student should have sufficient
skill to undertake the forging and welding of heavier sectioned metal.
The next exercises are designed to develop accuracy in forging to dimensions.
He will have learnt for himself that all smithing operations need a great
deal of practice and that he cannot expect to complete any of the exercises
perfectly the first time. It needs considerable practice to distinguish the
various heats, to hit the metal accurately and to deliver the blows at exactly
the angle required.
It cannot be stressed too often that the processes described in this book
are not the only ones which are used by smiths. Most men evolve their own
techniques, others adopt the methods which have been used in their own locality
for generations. The techniques described were are considered by the (now
defunct) Rural Industries Bureau the best for the student to learn; and are
those used by the Bureau's instructors.
Welded rings and chain links are included in this section; the following
general instructions on rings and the method of calculating the amount of
material required should be carefully studied.
RINGS
Rings which the blacksmith has to make fall roughly into three categories:
(1) Rings bent on the edge, ranging from washers to waggon
sweeps (the rings on which the forecarriage turns).
(2) Rings bent on the flat, ranging from ferrules to cart-wheel
tyres.
(3) Rings of round and square section of various sizes.
Metal up to 3/8" round or square need not be upset before scarfing the
ends as the welds can be made very quickly without wastage. All flat metal
and round and' square section above 3/8" must be upset before scarfing.
Square and round section metal must be scarfed so that the welding begins
with the ring flat on the face of the anvil. In the case of a small ring,
welding is continued with the ring over the bick, and with a large ring, from
the inside with the ring standing upright on the anvil face.
After welding, small rings are rounded up on a hand mandrel (Fig. 23), and
larger ones on a blacksmith's floor mandrel (Fig. 8).
To Calculate the Amount of Metal Required
When measuring off a bar which is to be bent into a ring, some allowances
have to be made for the metal lost-both in the bending and the welding. Most
smiths have their own methods of estimating these allowances, but a beginner
needs some simple practical system, such as the following, on which to base
his calculations.
(a) To determine the allowance for bending, add the thickness
of the metal to the inside diameter of the finished ring, and multiply
this figure by 31/7".
(b) To determine the allowance for welding, take the final figure
arrived at above, and add twice the thickness of the metal.
For example
To find the length of the metal required for a ring (shown in Lesson 14) with
an inside diameter of 6", made in metal ½" thick:
A. Inside diameter of ring 6"
Thickness of metal ½"
Total = 6 "
Multiply 6½"x 31/7" (π) =
203/8" (approx.)
B. Add twice the thickness 1"
Amount required = 213/8"
