cypher1024;3271951; said:I'm a little concerned that this design relies heavily on the shear strength of the eight screws that hold the top part of the frame to the uprights. I know the 2x4s provide some strength, but I wouldn't trust that frame long term.
hybridtheoryd16;3272309; said:M10 is metric 10 or 10mm diameter. Which is 3/8'' diameter or .375''.
Bolts also come in grades of strength and grade8 is a common very strong bolt.
For 3x3 timber I would use m10x127mm gr8 lag bolts, like you have pictured.
The only thing I would do differently on the stands is add a center vertical support.