First produced in 1939 in Gothenburgh, Sweden, and later made by the American Pullmax Company in Chicago, Illinois, the Pullmax metal cutting, punching and forming machines have gained an enviable reputation for reliable, long-term service. Depending upon their size, capacity and the attachments to hand, most Pullmax machines can undertake straight, circle, spiral, outer-circle and 4-way cutting, nibbling, slotting, louvring, punching, beading, joggling, edge bending, flanging, lock-forming and doming.
The way a Pullmax works is by employing two cutting tools--the lower one remaining stationary while the upper reciprocates. The moving tool penetrates the metal only part way, to the breaking point, this leaving a smooth, perpendicular edge that generally needs no further finishing. The amount of penetration of the upper tool varies with the thickness, type and hardness of the material being cut; e.g. in mild steel the penetration depth is approximately 1/3 the thickness. All but the "Trimmer" and the two smallest machines in the early range have controls to change thickness settings and speed, the latter usually in the range of 1000 to 3000 strokes per minute. By experience and experimentation, an operator can always set up a machine for its most effective action.
A fuller explanation of the principles of operation, tool setting and power requirements is provided below..