Simpson SWD Double Thread Screw

Exterior-grade SWD screws can be driven into framing members at less-than-90 degree angles to secure knee bracing or posts to beams, effectively replacing a hurricane tie.

When using on post-to-beam applications, one screw per beam ply is required.

Both pieces should be held in place before fastening, as they will not be squeezed together when screw is driven. 

Threads run the same direction (upper threads are not reverse-threaded).

Documentation for post-to-beam