Fullers are used in all cases that require recesses with curved bottoms to be made into any piece of work during its forging; and according to the width of the recess required, so is the width of the particular fuller employed. Fullers are used also for scarfing, in which case the end to be scarfed is put upon an anvil, or a bottom rounding tool, and the fuller is driven into that side of the work which is intended to be bevelled. Fullers are useful also for the drawing down or otherwise thinning of work that is too small for the ordinary set-hammer.

The forging of a fuller is properly done when the entire tool is made of one piece of steel, which is easily tapered, or upset at one end, until the required curve and thickness of fuller is obtained.

The mode of holding a fuller, or other similar top tool, during its use, is by means of either a straight ash handle or a tough rod, which is twisted around the outside of the tool, and tightly fixed with two iron clips. The straight handle allows the tool to be kept firmly upright, and should be used when good hammermen are comatable, who are not so liable to hit the handle instead of the tool-head; but the twisted handle is preferable when it is likely to receive a severe blow, which would break the handle without injuring the arm of the man who holds it.

Those tools that are intended to have straight handles should have the handle-holes punched and drifted, instead of being drilled, because the drifting spreads out the metal around the hole and strengthens the tool, the eye part being the weakest portion.

The final shaping of a fuller end is effected by hammering the tool while its lower end is heated and in a gap of a bottom rounding tool, the curve of the gap being that which is required for the fuller. Such shaping drives out a few ragged edges, named burrs, which are produced at the angular extremities of the fuller; these burrs are not hammered in, but filed off, and the curve of the fuller itself is also smoothed with filing; after which the fuller part of the tool is hardened, and is then ready for its handle.