Planer finish issue

You describe these as grooves, but are they actually raised? That would indicate small chips in the blade. The scallops are what I call “chip outs” (I don’t know where I got that, but I didn’t make it up myself). They usually occur where there is a change in grain direction and the knives are cutting against the grain, such as near a knot. They can be minimized by taking lighter passes or using sharp knives, but they sometimes happen.

-- Dale Manning, Carthage, NY

I’d say that if you took a look at your blades, up close, you would find many dents in the blades where they have hit harder things than they can handle. Can be anything from dirt to glue to nails to just a really stubborn knot. That would be the first thing, sharpen or change the blades.
Second, you said you have some scallops at the end. That is what we call snipe, where the board is off one infeed roller, still under the blades, and the blades take off a little extra at the end.
The general way to get rid of this quickly is to raise your infeed and outfeed table about 40 thousandths of an inch at the end of the tables in relation to the bed of the planer. It keeps the infeed end up and the incoming board down when entering, and the outfeed end up and the remaining wood down when coming out. There are other, more significant measurements you should make to ensure your planer is in spec., but for an initial fix, raising the tables a little is a nice quick fix. And change and or sharpen those blades!!

-- Paul, Tennessee, http://www.tsunamiguitars.com

If there raised your knives are chipped, to fix this you can either feed your work to a different part of the knives (more to the left or right).

If there not chipped try changing blades and taking lighter passes.

Also remember to feed your work with the grain not against the grain, you should make sure thats not the problem first. That won’t fix all the tear out if its the problem since its not uncommon for grain to change directions in the middle of a board but it helps a lot.

cedar can be very brittle to work with especially around knots.

Take care to brush off your stock with something like a wire bristle brush to get any dirt or silica etc before running through the jointer and then planer. That dirt can really dull knives quickly.

Like the others have pointed out take shallow passes and raise your infeed and outfeed tables to minimize the snipe.

Oh yeah almost forgot, it helps a lot to measure you board thickness before you set the planer height as many times I will find a thicker section than that at the end I am going to feed first. I will set to the thickest section to knock that down first.

You can tell if you have not done this if you see that little black arrow jump way up when you run a board through. That indicates it just hit a much thicker section than you had accounted for when you set your 1/32 pass.

Ask me how I learned this. The hard way!!