Overly thick walls slow production, invite porosity, and are expensive. Recommended maximum wall thickness for zinc die castings is .380”, and for aluminum die castings .250”. Nonuniform wall thickness and unnecessary material bulk should also be avoided because of differential contraction in cooling, often causing cracks.

Part strength should be increased by adding gusset-type ribs rather than by increasing wall thickness.

Ribs that strengthen flat surfaces should be narrower than the main wall of the diecasting and should be offset to avoid metal bulk at intersections. Perpendicular intersections are less bulky than angular ones.

Minimum practical hole diameter depends on metal characteristics, and maximum hole depth depends on hole diameter. For zinc die castings, recommendations are: minimum diameter, .040”, maximum through-hole depth, 8-diameters; and maximum blind-hole depth, 3-diameters. For aluminum die castings or magnesium: minimum hole diameter, .080”; maximum through-hole depth, 4-diameters; and maximum blind-hole depth, 2-diameters. In some cases, the holes can be cast from two sides. Large holes in thinwall sections of the diecasting should be reinforced with flanges to ensure that the area remains flat.

Exceptions to the general rule that edges of ribs and walls should be rounded are edges formed by meeting tool members. Such edges should be sharp, making the tool stronger and longer lasting. Similarly, feather edges should be avoided. A small land – .030” to .040” – is recommended.

Die castings can incorporate internal or external teeth, knurling, or other features for easy gripping. Only straight knurling is practical (diamond knurls require more complex tooling). Recommended pith is at least .080”, and knurl depth should be shallow. In addition to knurling, other possible gripping aids are small ribs, grooves, splines, and flats.