6mm~30mm HSS Twist Drill Bits Woodworking Drill Tools Kit Set Square Auger Mortising Chisel Drill Set Square Hole DIY Furniture Material: high speed steel Product size: 6mm, 6.4mm, 8mm, 9.5mm, 10mm, 12.7mm, 15mm, 16mm, 18mm, 20mm, 22mm, 25mm, 30mm Uses: used for woodworking stamping 1. This mortise chisel is very suitable for drilling square holes in wood with a mortise machine or mortise attachment. 2. Square hole drills cannot be used on electric drills, and square hole drills need to be used with square hole drills (tenon and tenon machines). 3. The mortise and tenon square hole is drilled in the middle of the combination by the terrible + outer sleeve. 4. Reduce the labor intensity of construction workers, speed up construction, and reduce construction costs in the construction, installation, decoration, and decoration industries. Model53A6H187S492466 Package Included:1 X square hole drill (optional) notes: 1. Manual measurement, please allow 1~2mm error, thank you.