We have been enlarging the slotted holes in shelf angles to make up for some misalignment problems. The engineer has rejected the work. What problems could enlarging the holes cause?
The holes in the shelf angle are typically slotted horizontally. These holes not only provide for adjustment but also provide relief for shelf angle expansion. The roughened edges of torch-cut slotted holes may restrict or restrain this expansion causing problems. Another problem is that the edges of a punched slotted hole in a galvanized shelf angle are usually coated with zinc; when these holes are enlarged with a torch the zinc is burned off. If these edges aren't properly recoated, localized corrosion may occur.