Coach bolt washer M16x50x3mm Steel Hot dip galvanized DIN 9021 Kramp - KRAMP
Coach Bolts M6 x 30mm Pack of 25 Carriage Bolts with Hex Nuts and Washers Zinc Plated Cup Square Bolts BZP DIN603 and DIN934: Amazon.co.uk: DIY & Tools
Is a carriage bolt as strong as a machine bolt? - Fine Homebuilding