If not welding a Kirncroft security door into a steel subframe, please follow the guidelines below: Fitting into brickwork: M8 x 50mm coach screw with 10mm rawl plugs. Fitting into blockwork: M8 x 50mm Coach screws with 10mm rawl plugs or M10 x 50 coach screws with 12mm rawl plugs. Fitting into a timber frame: M8 x 50mm coach screws or M10 x 50mm coach screws (no need for rawl plugs). Fitting into lightweight steel frame: No.14 (6.3mm) X 50mm self-drilling flanged hexagon tek bolts with a washer if required. Fitting into a heavy-duty frame (such as support beams or steel angles): M10 x 50 hex bolt sets. (Please note that the length of the bolts and screws should be taken as a general guide and may not be suitable for every situation).