My usual solution is to stand the end of the board on something below the vice and pinch one side of the board in the end of the vice and use an offcut to minimise the vice racking and hope it holds... Far from ideal!
Therefore, with my last dry (it hasn't stopped raining over here in the UK) scaffold board, I decided to make a poor mans version of the Moxon Vice (Utube).
Life started out by rough cutting the board to length. Raised beds function really well as saw horses. While sawing the board the cross cut saw started to bind indicating that there seemed to be a lot of internal stresses inside the wood. I had to finish the cut from the opposite side, at least its only a rough cut.
The next step was to rip the board into two pieces using my 5 ppi rip saw.
Again the saw started to bind and the wood actually split apart about ten inches before I completed the cut. Thankfully, the split was pretty accurate and not far from my marked line. After a quick assessment with the winding sticks it was time to get the boards flat and smooth.
For each board, I used my no#6 Foreplane to remove the rough saw mill marks and get a face basically flat and wind free before finishing it with my new Lie Nielsen no#7 Jointer plane. After the face I made one of the edges straight and square to the reference face.
Lastly, using a marking gauge, I marked all around the edge of the board before flattening the other face side to thickness and making it parallel with the first side. One thing I have learn't is always plane this second side across the grain towards the unfinished edge. If any spelching occurs, it will get cleaned up when completing the final edge. Finally, I made the last remaining edge square and parallel to the first edge.
With both boards basically four square, all that remained was to cut and square the ends on the bench hook.
The last remaining step to get a functional vice was to bore the holes in each end to accept the F-clamps.
With the vice essentially finished, all that was required was to soften the corners with a block plane and give the whole thing a light coat of Linseed oil to provide a bit of protection. I used a pair of holdfasts to attach the vice to my bench.
The distance between the clamps (width of board the vice is capable of holding) is just under 24" and I didn't think to make sure it was over 24" when cutting the ends square as the thing looked more than adequate for my needs. With hindsight, 24" is a good minimum capacity, as a lot of furniture uses 24" wide boards.
One last note, the vice might be handy for work away from the bench as it fits really nicely on my Saw Bench. If the sun ever shows up, maybe some dovetailing in the garden?...