10-9X3 1/2 6 Lobe Round Washer Deep Thread Wood Install Screw Long Type17 2/3Thread Zinc (Pack Qty 1,000) BC-1056DTRW17L

The deeper thread design offers greater resistance to pull-out forces. The round washer head is preferable in softer woods and offers a greater bearing surface than a countersunk design. The extra long chip cavity is preferable for use in thicker woods when a greater amount of material will be displaced C1018 - C1022 case-hardened steel Rockwell C 45 minimum