Machine Planing Sequence.

[pollys13]

I planed a board and it became wedge shaped,why?
Sequence: If I start with a bowed board and give it several passes until the face is flat, then edge. If the edge is not square with face, do I then edge, then face, then edge, face until all square. Or continue edging until square with the face. Then run through the thicknesser?
Also have a look at my reply to my other post.
RE: MACHINE SURFACE PLANING DOES PERFECTION EXIST? #1235980
By pollys13 - Fri Aug 10, 2018 6:12 pm
Thanks.

 

[peter-harrison]

If boards become wedge-shaped as a result of the planing process, it's because your outfeed table is set too high. (or if your outfeed table is fixed, your knives are set too low). Try planing a bit of flat square timber, slowly passing the front of it over the knives until it reaches the edge of the outfeed table. If you can feel it hit the edge even a little bit, it's too high. What will happen now is that as you pass more of the timber over the planer, the little bit extra now resting on the outfeed table will lift the workpiece a bit, which will mean a bit less is taken off the rest of the workpiece. This is cumulative, so the longer the workpiece, the greater will be the difference between the front and back ends. A bad notch in the knives can cause the same effect even if the table is right, because the ridge produced by the notch has the same raising effect.
As far as sequence goes, I always do the wider face first, to whatever quality of finish is required, and then the edge. Some odd- shaped boards or ones with difficult grain may need a different sequence, but it would take a lot of explaining!
Happy woodworking!
Pete

 

[custard]

-the outfeed table, instead of being flat, slopes down toward the cutter block
-the knives are blunt and are lifting the front of the workpiece
-operator error, failing to apply consistent pressure

As long as the error's very small it's often not that much of a problem, subsequent passes through the thicknesser will restore an even thickness.

 

[pollys13]

OK thanks.

 

[pollys13]

The wedge is across the face of the board not along its length.

 

[tomatwark]

If this occurs when you have put it through the thicknesser, it sounds to me that this is the issue.

Either the bed of the thicknesser is not set in line with the block or more likely you have not got the cutters in the block correctly.

If it is a planer thicknesser check the cutters against the surfacer out feed table at each side, if they are set correctly on all cutters, then it could be a problem with the thicknesser table, if not then reset them.

You are putting the face side down when thicknessing?

 

[custard]

I planed a board and it became wedge shaped,why?

Planed, or thicknessed?

 

[mbartlett99]

Have you recently changed blades? It sounds like either your table is out of square (check for any bits of crap that might have crept in when you flipped the table up last). or your blades are not aligned properly with the table - although this is a lot less likely if you have a tersa cutting block.