When I built my bench about four years ago, I hadn’t thought much about adding a planing stop, but I do often need to plane down pieces wider than my vise. The end vise and a bench dog work okay, but I really wanted a wide planing stop.
After a few experiments (the remnants of which are still visible), this is what I’ve come up with:
It is a piece of 1/2″ plywood reinforced with a 1″ thick oak strip. (I tried it first with just plywood, but without reinforcement the planing stop flexed too much in use. I had to cut out recesses in the reinforcing oak strip, however, to make the wing nuts accessible.) The plywood has slots cut in it to receive some 3/8″ threaded rod I epoxied into the end of the benchtop. The stop can be raised over 6″ high. Usually I use it at 1/4″-5/8″ high, but it’s nice to have the ability to raise the stop higher.
As you can see in the picture, I had originally had the rods in different places, but I soon learned that they should be as close to the edges of the stop as possible. Otherwise the ends flex under pressure. Two wing nuts make it easy to adjust the height. If needs be, I can even skew the stop, making it higher on one side than on the other. That’s handy if I’m planing down a batch of pieces of different thicknesses.
This is what the stop looks like in action. Ideally, the stop should be set 1/8″-1/4″ below the height of the workpiece being planed. Much higher, and you risk planing the stop, too, as you approach final thickness. Much lower and the piece may want to flip its tail up off the bench as you finish your stroke.
When not in use, the planing stop sits flush with the benchtop. I’ve been using it for a couple years now. Some days I wish it were prettier, but it always gets the job done.