Planer chip out

[Norm]

I've been planing some q-sawn wo and have been having trouble with chip out. I've tried freshly sharpened blades, taking less off on each pass and slowing down the feed rate but still get it. Anyone have an idea of what I'm doing wrong. It's a jet 15" planer.

[Den Socling]

It might be that the wood is over dried. I don't have much direct experience with surfacing but, if I over dry, tear-out is more of a problem because the wood becomes brittle.

[sawwood]

 Norm i have that trouble some times and what i do it run
 the board into the planer at a angle. This shear cut the
 face like you you if hand planing a curley lumber. Have
 planed one of the blanks you sent me and wow are they
 some nice figure to it.

 Sawwood

[Larry]

Over dry wood may be contributing to the chip out but there are ways to reduce it.  Check knife projection, chipbreaker, and feed rate just to make sure it is within specs.

On my Belsaw planer I had a lot of chip out on figured woods because the chipbreaker is rudimentary at best.  Ordered new knives from Belsaw with a back bevel which reduced the cutting angle.  Really helped to control chipout.  Seeing the improvement on the Belsaw we ordered knives for the Delta wedge planer custom ground from Schmidt.  Told them what we were planing and they figured out the knife grind.  They made a big improvement on that machine also.  Give them a call and see what they can do for you.

http://www.cggschmidt.com/index.html  

[Kirk_Allen]

I am in the middle of a complete kitchen cabinet job at my house and am using White Oak and have also used it for a lot of other projects.  I have found there are a few key tricks to preventing tear out.

1. I know this is a given but Ill say it any way.  Your blades must be very sharp.  
2. Take a wet rag and wipe down the side your going to plane just before planing it.  Wetter is better for this.
3. Run your board through the planer at an angle.  Now if you lucky enough to have one of the Baker or Powermatic planers this problem is fixed by having helical blades or inserts.
4. Take very, very small amounts of wood with each pass.  

The last step is even critical when your starting your initial sizing.  I had 1 1/8" boards that I wanted 3/4".  After the very first pass I had tear out that went deep enough to not clean up when I finally got the rest of the board to 3/4".  I didn't think I was taking that much off but when it comes to white oak, its the nature of the beast.

Now as far as the wood being to dry?  I dint know what it will do at a MC below 10% as this is the MC of my wood for my projects but it does make sense that dryer wood chips more.  This is proven by the fact that taking a wet rag to the board prior to its entry into the planer seems to all but eliminate the problem.

[Norm]

I've started grinding my own knives but had this problem with brand new knives. I'm using the same angle grinding as what they were new. Do you thing that a less aggressive angle would help.

[Paul_H]

Woodtech

Norm,
Larry is right on the money on the angles.I had some real problems on tear out on the knotty Fir and was refered to the link above.There should be more info on feed rates and hook angles.

I also found the people at CGSchmidt helpfull and if I was closer,would send my knives to them.I also have read that tearout worsens below 6% MC.I ended up having a 15 deg angle ground on the front of the knives.The front bevel was only 1/32 wide,but it made a real difference.

[beenthere]

A well-known source for machining problems, affects, and differences between species of hardwoods is the bulletin

http://www.fpl.fs.fed.us/documnts/usda/tb1267.pdf

I've been looking for another source for planer knife angles but can't seem to find it at the moment. Will keep looking. The hardwoods require different angles and jointing of the knives than do softwoods, if I remember correctly.

[Larry]

Norm,
Just had another thought.  When planing boards I am always looking for grain patterns to determine which direction I feed the board through the planer.  A simple pattern on a flat sawn board is where the "V,s " all point in the same direction.  That board goes through with the points of the V toward the infeed for a better finish.  Crotch and figured walnut get a closer inspection to see which way I want to feed.  Don't know if it would have any merit or not but the next time you get chip out on that QS oak take another pass only with the feed reversed and see what happens.

Never would have had the thought but I have been running the planer today and sometimes things get to be so routine that I do them subconsciously. ;D

[Norm]

I had forgotten about woodtech tooling, lots of good information there thanks Paul. I only get this on q-sawn wood and the worst is white oak but I do get some on red also. I had noticed that running it in a different direction helped also. I'm going to try a different angle and see if that helps. Since the planer is in an unheated shed it will be a few days until I get to it.

Thanks for everyones help, I sure appreciate it.

[woodmills1]

I get tear out on white oak and maple.  The info on double angle sharpening and on feed direction is right on.  Even on a jointer oak and maple are very sensitive to feed direction.  As far a wetting the surface that sounds really promising.

[Fla._Deadheader]

  Finally got 1 of the 2 Belsaw Planers home, lastnight.

  While inspecting it, I noticed the knives are ground with 1 angle. Question is, what's a chipbreaker??? Been seeing that term a lot lately??? Is it where the back side of the knife lightly hits the board as the board moves through the machine???

[Larry]

On your Belsaw there is a curved piece of metal welded to the bottom of the hood right behind the arbor.  It drags along the board on the outfield side.  If the planer has been used a lot it is probably wore out especially in the center.

[shopteacher]

FDH:  The chip breaker is a spring loaded(sometime segmented) or heavy weighted casting right behind the cutterhead and knives. As the knife begins to peel a sheet off the board it is lifted against the chipbreaker and snapped off. Otherwise it would be peeled off like the rind of a Flordia orange and jam up the exhaust area in an instant.

[beenthere]

FDH
See p 5 of the following for a planer machine workings:

http://www.fpl.fs.fed.us/documnts/usda/tb1267.pdf

That should help with what others are saying too.

[shopteacher]

beenthere, that's a great follow up. I was trying to find an illustration to post, but couldn't find one handy.  One of the great things about this forum is the team work and effort put forth to help each other.