Pan head or countersunk screws

I must admit I have never quite understood the use of gutter bolts and square nuts (on the outside) with trunking. "Proper" nuts have not been square since the 19th century, and why they are favoured by some electricians appears to be hidden in the long lost past. The usual reason for gutter bolts (sometimes as long as 50mm) seems to be that the job is being made as difficult as possible, in that it is almost impossible to hold the head still when tightening to a suitable torque, without the use of pliers or more complex tools, and electricians cannot be bothered to source bolts of the correct length. 5mm long conventional hex bolts and nuts have little or no thread exposed and can be fitted and tightened with a spanner and socket, using an impact driver if you have one, about 10 seconds each. If you want a bit more length tolerance simply use nylock nuts. Trunking cables should not be "drawn in" anyway as there are still sharp edges to bends and cut lengths, but placed in carefully, when no cable damage will occur. Proper bolt threads and ends are not at all sharp, and star washers under the nut will make much better electrical connections, probably with 6mm bolt length. Countersinks are impossible in sheet metal of 1 or 1.2mm thickness unless very tiny bolts (m3) are used and there is no drilling tolerance available. The question is why use gutter bolts (at huge prices from the wholesaler) when the proper engineering ones are cheaper and readily available (although Screwfix does not have the short lengths, although fixings wholesalers do). A Brummie screwdriver for trunking work is a bodgers tool!

I must admit I have never quite understood the use of gutter bolts and square nuts (on the outside) with trunking. "Proper" nuts have not been square since the 19th century, and why they are favoured by some electricians appears to be hidden in the long lost past. The usual reason for gutter bolts (sometimes as long as 50mm) seems to be that the job is being made as difficult as possible, in that it is almost impossible to hold the head still when tightening to a suitable torque, without the use of pliers or more complex tools, and electricians cannot be bothered to source bolts of the correct length. 5mm long conventional hex bolts and nuts have little or no thread exposed and can be fitted and tightened with a spanner and socket, using an impact driver if you have one, about 10 seconds each. If you want a bit more length tolerance simply use nylock nuts. Trunking cables should not be "drawn in" anyway as there are still sharp edges to bends and cut lengths, but placed in carefully, when no cable damage will occur. Proper bolt threads and ends are not at all sharp, and star washers under the nut will make much better electrical connections, probably with 6mm bolt length. Countersinks are impossible in sheet metal of 1 or 1.2mm thickness unless very tiny bolts (m3) are used and there is no drilling tolerance available. The question is why use gutter bolts (at huge prices from the wholesaler) when the proper engineering ones are cheaper and readily available (although Screwfix does not have the short lengths, although fixings wholesalers do). A Brummie screwdriver for trunking work is a bodgers tool!