I need to get through metal lintels to install blinds (which sometimes are heavy) into window reveals. I have watched a YouTube video which showed a tradesman using an SDS drill for drilling the holes in masonry but when he encountered a metal lintel he switched to a 3mm high speed twist drill bit. When he carried out this switch he seemed to change the actual chuck of the drill to accommodate this drill bit. Could anyone give me any advice on what frill bits to buy and if I need to change the chuck of the drill for HSS drill bits? I am having so much trouble fixing the blind brackets into the metal lintel, I am going through 18mm plasterboard then encountering the metal lintel. I then use a small Erbauer metal drill bit for a pilot hole and then further sizes up until I get a 4mm hole. I then have an issue with the screws I use to screw through the metal lintel, there are so many suggestions on YouTube, again could someone tell me exactly what I need to buy? I am currently using a Makita drill for both masonry and metal (switching drill bits) I have never considered the SDS drill for drilling through the metal lintel. In fact I have only used the SDS drill once to get through a concrete lintel, They seem mainly to be metal. Is there a cute way to locate the hole in the metal lintel I have just created to locate the relevant screw? Do I plug this hole for a better fixing? In many cases the out side of the plaster cracks around the screw hole making it look so much bigger and uglier. I am a novice trying to make my way as a curtain and blind fitter for a local company but I am getting increasingly worried and frustrated when turning up at a customers address not knowing what I am going to fix to. Any constructive suggestions as to what to use for this kind of issue would be greatly appreciated, trust me! Especially the actual Screwfix products I should purchase to achieve an acceptable outcome for the customer. I eagerly await your learned recommendations.