If the whole point of washers is to disperse the force of screws and nuts to prevent them from digging into the material, why not simply create screws and nut heads with
![Hex Head Lag Screw with Washer, Coarse Thread, Lag Point - Hot-Dip Galvanized Steel - Reliable Fasteners Hex Head Lag Screw with Washer, Coarse Thread, Lag Point - Hot-Dip Galvanized Steel - Reliable Fasteners](https://www.reliablefasteners.com/documents/docsGr/119/427/9/1194279/1418523_300.jpg)
Hex Head Lag Screw with Washer, Coarse Thread, Lag Point - Hot-Dip Galvanized Steel - Reliable Fasteners
![3/8" x 10" Zinc Lag Screws w/Flat Washers, Grade A, Quantity 25- by Fastener Depot, LLC: Amazon.com: Industrial & Scientific 3/8" x 10" Zinc Lag Screws w/Flat Washers, Grade A, Quantity 25- by Fastener Depot, LLC: Amazon.com: Industrial & Scientific](https://m.media-amazon.com/images/I/21V--kuk8qL._AC_UF1000,1000_QL80_.jpg)
3/8" x 10" Zinc Lag Screws w/Flat Washers, Grade A, Quantity 25- by Fastener Depot, LLC: Amazon.com: Industrial & Scientific
![Hillman 5/16-in x 3-in Black Hardened Round-Head Exterior Lag Screws (4-Pack) in the Lag Screws department at Lowes.com Hillman 5/16-in x 3-in Black Hardened Round-Head Exterior Lag Screws (4-Pack) in the Lag Screws department at Lowes.com](https://mobileimages.lowes.com/productimages/7ba69e0f-4a0d-442b-ba26-5dfa40161bc8/02102929.jpg?size=pdhism)