When attaching a steel frame to a timber one from the timber side, drill a clearance hole through the timber and screw a long self-drilling screw into the steel. If you are fixing from the steel side, use a 12# x 40mm type 17 screw.
When attaching a steel frame to a timber one from the timber side, drill a clearance hole through the timber and screw a long self-drilling screw into the steel. If you are fixing from the steel side, use a 12# x 40mm type 17 screw.