Planer Thicknesser Playing Up...

[cowfoot]

Hopefully someone here can help before I have to get on the phone to Record Power...
My planer's taking big bites out of stock (see photo) - in fact it's pretty much throwing it back at me!
I've put fresh knives in, checked and checked again that they're set at the right height and established that the tables are level.
Any ideas?

 

[Wildman]

looks like you are putting a long length through that is unsupported on the output side.

 

[cowfoot]

That board is 40cm, it's a close up!

 

[custard]

I know you say everything's set up right with sharp knives, but that's just not the case. For one thing you've got the planer set for an excessively heavy cut relative to the workpiece, the workpiece is riding up over the knives for a short distance then dropping back down into them. Back off the cut, check everything, and try again.

It also looks like a pretty thin workpiece, although that could just be the photo. Thin workpieces are tricky to plane, you need ultra sharp knives and a sensitive but firm application of pressure, initially on the in feed table but quickly transferring that pressure to the out feed table and keeping that pressure closer to the cutter block than you would with a thick, heavy workpiece.

It can help on thin workpieces to set the guard so it is applying some of the pressure (easier on some guards than others), or if your planer is wide enough you can feed in the workpiece at a slight angle.

Good luck!

 

[cowfoot]

Thanks Custard.

 

[sunnybob]

40 cm is too small for my thicknesser. The board needs to reach front and back rollers AND the anti kick back tines.
Get a much longer board to use as a sled, HOT glue your piece to the middle of it, and glue two sacrificial pieces either end of it.
That way you have fooled the planer into thinking its one long board.
Then take the smallest cuts the machine will make untill you have the correct thickness.
Also, make sure the sacrificial pieces grain runs the same way as the middle piece. Cross grain through a thicknesser is quite spectacular.

 

[RobinBHM]

It looks like bounce to me, workpiece is a bit short and a bit thin.

As Custard says light cuts only!

 

[toolsntat]

For surfacing work remember the tables should be set so the outfeed is level with cutter knives.
If that is thicknessing, knives are too far out of block or feed in and out rollers need adjusting.

Andy

 

[toolsntat]

Any joy getting it sorted?

Andy