I am planning to start making some spare parts myself, to improve the reliability for my business. The spares I need the most, because of quality and availability problems with my suppliers, are perforated steel sheets for vibratory cleaners and helicoid flighting for screw conveyors.

Can you point me to good books on the subject of metal forming these kinds of parts?

For perforated steel sheets I know I need a CNC punch press, but I am not sure of the tonnage, the speed, the general model, the size of the table, etc. The local suppliers I have contacted want to know this kind of things to quote me. They say they can't find out just by my description of the holes I want to punch press. The specs of the sheets are these:

thickness - min 0.75 mm, max 3 mm

width - min 750 mm, max 1000 mm

length - min 1000 mm, max 2000 mm

hole width - min 1 mm, max 18 mm

hole length - min 1 mm, max 35 mm

material - mild steel (SAE 1010 or 1020)

The open area, for the most common holes, like 1.6 x 20 mm and 3.17 x 19 mm, is usually around 45%. For the very small holes it is around 22%, for the largest ones might be around 65%.

I would like to have a rough idea of price of punch presses and tooling. Used equipment would serve me well.

As for helicoid flighting I have found only one supplier of machines to make them: Lenham, in the UK. Perhaps there are other methods that you know.

The helicoids I need go from 120 mm to 400 mm of outside diameter and from 38 mm to 116 mm of internal (shaft) diameter. The pitch is usually the same as the exterior diameter, but could 3/4 or 1/2.