frictional fit restricting movement of the screw when it is subjected to vibration

1/2 x 14 Hex Lag Screw Zinc Plated

which means you can place them close to each other without having to worry about compromising structural integrity

1-8 Finished Hex Nut Silicon Bronze

1 1/4-7 Nylon Insert Locknut Zinc Plated

3/8-16 x 4 Hex Sleeve Anchor Zinc Plated (50) 5/8-11 Socket Cap Screws 316 Stainless Steel frictional fit restricting movement of3 8 16 x 4 Hex Sleeve Anchor Zinc Plated (50) . SLEEVE ALL sleeve anchors are pre assembled expanding sleeve anchors for use in all types of solid base materials. Download Simpson SLEEVE ALL Sleeve Anchor Technical Data