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Uneven board thickness from planer

Started by alan gage, February 26, 2021, 01:02:21 PM

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alan gage

I've noticed that my planer doesn't always produce consistent thicknesses. The problem isn't side to side, like if the bed wasn't parallel with the head, but rather along the length of the board where it might be thinner towards one end or in the middle.  The difference isn't terrible, maybe 1/32" of an inch, but I struggle to understand how it's happening.

For example I recently planed hardwood flooring for my house. All the lumber went through the planer in one batch with no adjustments made to the planer height so I figured they should all come out exactly the same thickness. After putting the tongue and groove on them I found they didn't match up consistently. I started measuring the thickness of the boards and found variations. It usually wasn't the entire length of a board that would be too thin but often only half of the 8' length (for example).

The planer is a Woodmaster 718 with spiral head.

My best guess is that the boards, even when jointed flat, are raising off the table between the rollers. Because the Woodmaster can accept moulder heads and saw blades there is more distance than normal between the infeed and outfeed rollers with no pressure plates, which could make the boards more prone to lifting.

As I understand it one of the reasons snipe occurs is because the cutting motion of the head is pulling up on the board. I'm thinking this may be happening to my boards at times even when they feed rollers are both engaged. It does seem to happen more with thinner stock.

Any thoughts or solutions?

Alan

Timberking B-16, a few chainsaws from small to large, and a Bobcat 873 Skidloader.

Larry

Larry, making useful and beautiful things out of the most environmental friendly material on the planet.

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alan gage

Quote from: Larry on February 26, 2021, 01:54:04 PM
Did you joint one face before planing?
Yes and no?

The floor boards were resawn from already air dry cants (11-12%) and then stickered for final drying before planing. I didn't notice any bowing, cupping, or other bad behavior so I skipped the jointer. That's not to say some couldn't have had some bow, or a tendency to be leaning that way.

I'm really not sure if the thinner boards have more of a problem or if it's just a nature of their usage (flooring that needs to be flush) that make it more noticeable. For most of my uses I wouldn't notice if a couple boards were 1/32" off.

Another thing I notice, sometimes more than others, is a pattern on the face of the board left from the spiral head. Usually the surface looks nearly perfect, sometimes if I catch the light just right I can see a checkerboard pattern from the cutters, and rarely the pattern is quite noticeable and even felt to the touch.

A couple nights ago I was planing some 9/16" walnut panels that had been face jointed. They showed the worst checkerboard pattern I've ever seen and it took considerable sanding to get rid of it.

Oh, and another thing I just remembered is that sometimes my boards come out with very narrow ridges, maybe 1/64" tall, across the entire width of the board, usually fairly evenly spaced like every 3-4". Can hardly be due to the cutters since it's a spiral head. I have a hard time figuring what could be causing that. Certainly doesn't do it all the time.

Alan
Timberking B-16, a few chainsaws from small to large, and a Bobcat 873 Skidloader.

Don P

One thing comes to mind to check, are your jack screws worn?.  Is there a lock on thickness ... jack into position and then some type of column lock, or is thickness simply based on the screws themselves?

LeeB

Possibly the ends are sagging as the board gets to the mid point causing the middle to raise a bit into the knives?
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GAB

Quote from: LeeB on February 26, 2021, 04:24:51 PM
Possibly the ends are sagging as the board gets to the mid point causing the middle to raise a bit into the knives?
I'm thinking along the same lines as LeeB.
Try supporting the boards the entire length on both sides, of the planer action area, and see if that makes a difference.
If the board is not properly supported I can see the center being thinner because a side view of the board would be arced shaped.  The end of the board, if the already planed end is not supported, could be even thinner.
I hope you let us know what the rest of the story is as I have the same model planer and just received the spiral cutter head I ordered for it.  It is still in the box as it is too cold to mess with that this month.
GAB
W-M LT40HDD34, SLR, JD 420, JD 950w/loader and Woods backhoe, V3507 Fransguard winch, Cordwood Saw, 18' flat bed trailer, and other toys.

Crusarius

the lines could be from nicks in cutters. I just got a new planer and already chipped 2 inserts. I now have lines. I also nnoticed your checkerboard pattern. that is tool chatter. not sure how to get rid of that.

21incher

Quote from: Crusarius on February 26, 2021, 05:07:48 PM
the lines could be from nicks in cutters. I just got a new planer and already chipped 2 inserts. I now have lines. I also nnoticed your checkerboard pattern. that is tool chatter. not sure how to get rid of that.


A shelix type helical head is the only way according to Grizzly tools tech support. You sure they didn't  have chips out of them from the factory?  My grizzly planer came with improperly ground inserts from the factory and they all had to be replaced when new that helped a lot with  cut quality. 




You should pass this question to Woodmaster as I bet they will have suggestions.  Never seen a tapered board come out of a planer. Just some with  snipe on the ends. You sure the boards were pressed down on the shaper enough to keep the t&g consistent from the edges.  
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Larry

On my machine, I have a corrugated infeed roller.  It presses on the wood and leaves a pattern which the cutter cuts away, unless I take a real light pass than the pattern is not fully cut away.

My machine came with a Byrd Shellix head installed.  When I got it the head left two or three faint ridges just as you mentioned.  Didn't bother me much as they sanded away so fast.  The first time I rotated, I removed all the cutters and cleaned the head with acetone, wire brush, and compressed air.  After I re-installed the cutters the lines were gone.  I assume there was a metal chip or something under a couple of the cutters from the factory.
Larry, making useful and beautiful things out of the most environmental friendly material on the planet.

We need to insure our customers understand the importance of our craft.

alan gage

Quote from: LeeB on February 26, 2021, 04:24:51 PM
Possibly the ends are sagging as the board gets to the mid point causing the middle to raise a bit into the knives?
I like this idea and it makes sense. Not saying it's the cause for sure but it jives with it seeming to happen with longer and thinner boards. I usually try to support my boards on the in/out side of the planer but on my recent run of flooring I had no supports and was hustling back and forth feeding and catching as I was feeding multiple boards at a time so I couldn't hold them by hand either. I'll pay more attention to this.
QuoteYou sure the boards were pressed down on the shaper enough to keep the t&g consistent from the edges.  
Yes, they went through the shaper with a powerfeeder and after I noticed some of them not matching up correctly (which the initial test pieces did upon setup) I started measuring board thickness with a caliper and found the variations.
Quotethe lines could be from nicks in cutters
QuoteMy machine came with a Byrd Shellix head installed.  When I got it the head left two or three faint ridges just as you mentioned.  Didn't bother me much as they sanded away so fast.  The first time I rotated, I removed all the cutters and cleaned the head with acetone, wire brush, and compressed air.  After I re-installed the cutters the lines were gone.  I assume there was a metal chip or something under a couple of the cutters from the factory.
Are you guys talking about ridges running the width of the board or across? Mine run across so shouldn't be chipped cutters. I've turned cutters and noticed them before and after. I assume it's some kind of harmonics like the sawmill leaving ridges when cutting too slow. Like you said these, when they show up, sand off very easily but I'm puzzled by how they occur (not always).
I'll be running some walnut through the planer this coming week and will pay close attention to thickness variations and see if different supporting methods help.
Thanks for the ideas. Hope it doesn't sound like I'm beating up on Woodmaster. It's a fine machine and overall I'm very happy with it. These are pretty minor issues and mostly just bother me because I struggle to figure out how it's happening and why sometimes they show up and not others.
Alan
Timberking B-16, a few chainsaws from small to large, and a Bobcat 873 Skidloader.

btulloh

Those ridges you're describing are from the feed roller. Might need to try backing off the pressure.
HM126

alan gage

Quote from: btulloh on February 27, 2021, 09:05:09 PM
Those ridges you're describing are from the feed roller. Might need to try backing off the pressure.
Not doubting you but just trying to wrap my head around that.

I have the feed rollers adjusted to factory spec and to my eye the rollers (rubber) look ok.

Thinking about the regular pattern of those ridges (every few inches) I can see how it could possibly be from a feed roller (once every revolution) but I'd think it would have to be the outfeed roller and it seems like it would be easier for it to make a depression than a standing ridge.

Alan
Timberking B-16, a few chainsaws from small to large, and a Bobcat 873 Skidloader.

Don P

I'll bet it is all tied to not supporting the boards. If they are hanging they are also probably getting a harmonic kind of bounce going that is minutely gouging them.

btulloh

Quote from: alan gage on February 27, 2021, 09:58:35 PM
Quote from: btulloh on February 27, 2021, 09:05:09 PM
Those ridges you're describing are from the feed roller. Might need to try backing off the pressure.
Not doubting you but just trying to wrap my head around that.

I have the feed rollers adjusted to factory spec and to my eye the rollers (rubber) look ok.

Thinking about the regular pattern of those ridges (every few inches) I can see how it could possibly be from a feed roller (once every revolution) but I'd think it would have to be the outfeed roller and it seems like it would be easier for it to make a depression than a standing ridge.

Alan
Sounds like a different kind of feed roller than what I'm used to, so I retract my comment. Can't be variation in knife height since you're running a spiral head. I'll just back out of this one quietly and pull the door shut behind me.  Curious to see how it turns out though. 
HM126

farmfromkansas

I had the same planer some years ago, and it had like foam rubber on the feed rollers.  So they might give a little if you run a long board through unsupported.  Maybe you could make your flooring from shorter lengths, would help with that.  I know we all like long flooring boards.
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