Thicknesser tearout question

[noddy67]

I have a felder planer thicknesser with new blades on it. Milling up some ash recently I was getting a great smooth finish when planing the first face but on almost every board I'd get pretty poor tearout when thicknessing the other face after converting the machine to its thicknesser mode.

I varied the depth of cut from 0.6mm to 0.2 mm without it helping much. Also as best as I could I made sure the grain orientation was correct.

Any ideas what the cause might be or was it just the specific boards?

Many thanks.

 

[blackrodd]

As you said you're cutters are sharp, My first guess would be you are either going against the grain,
Or you have chippings and waste extraction problems, leaving a woolly and dimpled finish,
as the waste gets chocked up.
Either pay more attention to the grain, or get you're extractor working more efficiently.
Ash is usually an easier wood to machine and work and after Elm, one of my favourites.
HTH Regards Rodders

 

[dzj]

Check the blades again, maybe they're not as sharp as you think they are.
Also check feed roller spring tension, or if there is some dust or something preventing them to be fully
seated in the lowest position and properly adhere to the board.

 

[PAC1]

Daft question is it set on the slow speed on the feed roller

 

[owen]

Check the dust extraction, if that's blocked, you'll get a rubbish finish

 

[noddy67]

Great thanks for the feedback chaps. Will check the dust extraction.

 

[custard]

It planes the boards satisfactorily.

It thicknesses the same boards badly irrespective of cut thickness.

Most likely explanations are feeding the boards into the thicknesser the wrong way round and/or the thicknesser is set on the high speed setting.

After those you're down to less plausible explanations, like the last board to be planed had been lying on the floor and the grit in the grain blunted the knives, or the springs on the thicknesser pressure bar have just given up the ghost.

I also use a Felder planer/thicknesser and if a board planes well then it'll almost always thickness even better, in fact I generally plane just enough to get enough flat reference surfaces dotted across the face of the board, then thickness the opposite face, and finally thickness the original planed face to take advantage of the superior finish that the Felder thicknesser delivers.

Good luck!

 

[PAC1]

I do exactly the same and try to make the last two cuts 0.5mm or less taken from each side