Frame cramps can be fixed to concrete, steelwork or masonry A single 7mm diameter hole or an 8mm x 30mm vertical slot. Ancon M6 Single Expansion Bolts are recommended for fixing to concrete, set screws or self-drilling screws for steelwork, and suitable plugs and screws for fixing to masonry. Large washers must be used with all SDVs and similar ties with a slot. SDV ties fixed to steelwork or concrete at the lowest point of the slot will have a safe working load of approximately 1kN. This capacity reduces as the fixing is moved away from the bend.