I was hand planing this morning the edges of two 2x4s and with a combination square checking for squareness. But how does one check the board surface from one end to the other to make sure it's straight? One way is to use a 3' or 4' metal rule on edge. But what if your piece is longer. So I used this technique and it works very well.

Edited May 3May 3 by MrRick

Love that man! An International Treasure. MHO.

To be blunt, I never care much. If it fits with it's mating piece, I'm content. So when long jointing for something like a table top, I will clamp the two boards together and plane both edges at once. Usually I add a bit of spring too. It's a well known technique so I won't go into the advantages.

When doing something like fitting a door, I just make it match the opening.

I could see cases where I would need straight though - like if I did a lot of rule joints or something, then my typical method would be less efficient than working to a common reference.

Really it's a lot like tails vs pins 😀 At the end of the day, there are many, many ways of skinning the woodworking cats.