Cost Comparison – ASSY Screws Versus Lag Screws

Cost comparison between different fastening technologies must consider the entire picture to have any relevance. A fastener-to-fastener cost comparison leaves out important information that affects the total cost of the connections, including:

• Cost per unit of resistance
• Time to install including related labor costs
• On-site construction procedures
• Cleanliness on construction site (no pre-drilling equals less saw dust)
• Fastener applications
• Extra tools or materials required (no pre-drilling equals no need for a drill bit)
• Quality and architectural appearance of the finished assembly
• Logistical costs (ex: exchanging tools and bits, moving ladders, and so on) for large projects

Time savings generally add up to large cost reductions, while for small projects this will have less of an impact. A fully threaded screw may cost more than a similarly sized lag screw, but inclined screw applications allow for higher capacities with fewer screws in smaller timber sections. The figure below shows a short example: