can you plane endgrain?

So long as it's reasonably thick, then you can do this without disaster. There will be breakout on the trailing edge though, so the easiest way to deal with that is to make it oversize and saw it down later. You could try putting a lipping on instead, but that tends to splinter on the cross-grain edges.

It won't feed through the rollers (at first) because it will be uneven. Take a thin board a few feet long and use that as a push stick behind it.

-- Die Gotterspammerung - Junkmail of the Gods

You might also consider a sharp, finely-set low-angle block plane.

If you do go down the planer route, take very light cuts. Cheers

Frank

You can fasten two rails along each side before passing it through the surface planer. That will prevent snipe too.

That is the one job I would consider blowing the dust off of my belt sander for. Probably the only one.