Planer ripples

[SoftWood]

I have an issue with a new to me planer that I'd hoped a more knowledgable person could answer.  It's a helical planer but I'm getting these ripples on the face, some seem deeper than others but pretty uniform.  The planer is out of adjustment somewhere I'm positive, but I'm not sure where.  Can feel them with your fingers but they aren't visible unless I get the light hitting the face right.  

[Larry]

Right out of the box I'm gonna say that the board surface ran through a planer is never ever a finished surface. It will always have some degree of ripples. Sharp straight knives are the best followed by a helical planed surface.

Looking at your picture (great picture btw) the surface does look like it has some excessive ripple. Is the opposite face of the board smooth before you run it through the planer? Next I would check and clean the bed rollers with lacquer thinner to insure there is no build up of sap or wax on the roller. If the roller looked to be perfectly clean I would put a dial indicator on it to check for runout as you turn the roller. If you don't have a dial indicator just lower the rollers below the bed so they don't contact the board. If still having problems I would start looking at the head. If the inserts have been turned but the seat on the head not completely cleaned this could cause a problem. Bad bearings could also cause a problem. If the head was made in China I would suspect quality problems.

I don't get too excited if I see a little ripple on a board out of my planer. I know it will clean up with a quick swipe of the ROS using 150 grit or even hand sanding.

[Dan_Shade]

How long have you used this planer?  Has the planer created fewer / less pronounced ripples in the past?

As Larry described, a planer will only get you close to flat. 

[YellowHammer]

We really need to know more about the planer.  What brand, is it lunchbox, four post, production, does it have bed rollers, are they adjustable, does it have a chip breaker?  Urethane pressure rollers or steel?  As Larry indicates, some can be caused by the bed, some can be caused by the head, some can be even caused the adjustment of the pressure rollers, springs, and pressure bar.

Typically when that pattern is seen, beside the cutter bearings being too worn, the ripple are caused by the board being lifted into the cutter head, or being driven into the cutter head.  The board is coming up, when it should be held down. 

[SoftWood]

Hmm that might make sense.  The only change I made was that I went through the manual and set up the bed rollers, they were set flush with the bed so I raised them up .004" above the table, as per the manual.  
It's an older 4 post Steel City model with chip breaker.  
Played with a few things afterward but nothing was a 100% fix. 
I tried running slower feed rate and taking less material off, that seemed to make the ripples less pronounced but still there.  I couldn't wrap my head around what was happening; is there too much down pressure and the board is springing or chattering with the cutter head or is there not enough down pressure and again the board is bouncing. I didn't clue in that it could be the bed rollers and I thought I was helping things out by setting them up properly.  

The finished product I saw coming out previously was pretty flawless and didn't have any ripples whatsoever.   

[customsawyer]

Check the down pressure of your chip breaker also.

[YellowHammer]

If you have ripples on one side and put that side down on the raised bed rollers, the board is only supported by the bed rollers and the washboard riding on the bed rollers will magnify the effect against the cutterhead.  In essence, the washboard against the rollers are driving the board into the cutters, following and even increasing the washboard pattern.  Even though you have a lot of planer bed, the only thing the board is riding on is the little bit of bed rollers, so eliminate them from the troubleshooting equation.

Drop the rollers all the way, they need to be submerged into the bed for troubleshooting, and feed in a board in fully supported only by the bed.  The top side should be noticeably flatter than the rippled bottom.  Then flip the board over, and do it again.  You should see an improvement.  You should also look for signs of wear on the bed, is flat and not tapered, wedged, etc?

If not, then for some reason the board is still being "lifted" into the cutterhead, and so increase the down pressure on the feed rollers and pressure bar, and decrease the clearance spacing of the pressure bar.  Drop the pressure bar until the board will not feed, then gradually lift it so that the board barely squeaks under it, a properly adjusted one only has the clearance of a coat of spray paint.

When I adjust bed rollers, I set them so that they just barely touch the bottom of the board, their only purpose is to take a little load off the feed motor and reduce wear on the bed, but they reduce the quality of the finish if they are raised enough to raise the bottom the board off the bed.  So they should not be raised enough to allow the board to actually be lifted off the bed, or the board will "spring" and chattering.  You can run a short thick piece of wood tough, and the chatter should reduce and look for a snipe mark where the board "falls off" the fort bed roller, if you see that, the roller is set too high.      

[Brad_bb]

I don't know if this could even be related, but I remember a post awhile back where the problem was planer chips getting in between the board and rollers.  Does anyone remember that post and what it was doing to the board?  Was it ripples like this?

[SoftWood]

I lowered both bed rollers to flush with the bed or just a c hair under, and I increased the feed roller a little and the outfeed roller a lot.  Only went 1/2 turn on adjustment and tried the board but ended up 3 turns I think.  

Definitely less rippling now but not where it was previously which has me confused.  Can run your finger down it and put a light at every possible angle and cannot see or feel a single peak or valley on that board, it came out very smooth.  Now with adjustments I have less rippling than when I made my first post but easily felt.  I've run my load through the planer for now & hopefully the drum sander will take the minor rippling out when I get there.  
Maybe I am trying to get too picky.  

Thank you for the assistance and advice!

[Tom K]

If I remember correctly the issue in the post Brad is referring to was caused by lack of suction on the dust collector. The chips were not getting pulled out and were getting pressed into the surface by the outfeed roller, yours does not look like that.

What type of helical head do you have? Have you replaced the blades recently? If you've adjusted everything as much as you can and it didn't solve it I would lean towards something in the head or knives. If it was better when you fed slower maybe the motor is going out and lost RPM's, or you have a bad power supply?

[YellowHammer]

Did you flip the board over after every cut?  If the bottom is rippled, and one pass makes it better, then flip that side down, run the new top side and then flip that side down and rerun the first side.  That should now be extremely smooth.