General description Specifically designed to attach wood to light section steel (max. 3mm), the TIMCO Self-Drilling Wing-Tip Steel to Timber Light Section Silver Screws are ideal for various construction and DIY projects. These screws feature a coarse self-tapping thread with wings that ream out the timber, allowing for maximum revolutions per minute (R.P.M.) without burning out. When the wings contact the metal, they break off to provide a secure fit. Technical specifications Dimensions: 4.2 x 38 mm Material: Steel Finish: Silver Maximum steel thickness: 3 mm