All hardware associated with Project Cedrus is Metric 8mm with 1.25mm thread pitch (M8x1.25). Damage from impact and/or strain due to fatigue and heavy use can cause bolts to elongate or bend. Even hardware from OEM setups will wear with time, and replacement is recommended whenever bolts loosen unexpectedly. You can easily check thread pitch for damage by comparing a new fastener to old; the threads should line up ridge to ridge. If they don’t, the bolt has strained and it will not stay tight and potentially damage the mast. All Project Cedrus hardware is sourced from McMaster-Carr and you can determine exactly which hardware you need from product drawings and comparing them to your existing screws. Or, if you prefer, we can prepare a kit based on images of your adapters for basically the cost of shipping. We’re not trying to make money on screws, and we want your setup to be solid! As a reminder, please read the Owner’s Info section for detailed explanations of how to properly assemble your setup and diagnose any problems. Also, despite popular belief, A4 and A2 hardware are equivalent from a strength standpoint. While A4 may have better corrosion resistance, it takes many years for the true difference to become obvious. Marine hardware on sailboats designed to last 50+ years may benefit from 316 grade (A4), but it’s less critical in foil applications. You are free to use the hardware you wish, but please verify strength values (yield, ultimate) before deviating from recommended hardware. As discussed on the blog, DO NOT USE TITANIUM HARDWARE. We are not liable for lost equipment due to hardware deviations from Cedrus-supplied A2/A4 70-80 screws.