Planer issues powermatic pm221

Started by JRWoodchuck, November 23, 2022, 09:06:11 PM

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JRWoodchuck

My planer does this crazy snipe occasionally not always but when it does it's pretty much at the same spot on a board. I dropped my bed rollers to below the bed to rule out a bad roller and it still does it. And it's always on the right side of the planer bed. You can see how it fades to the left side. Any thoughts? These are drawer bottoms that are full width for the planer at 20". 
Home built bandsaw mill still trying find the owners manual!

firefighter ontheside

I would say down pressure on feed roller on that side is not holding the board down.  Also, any chance the knives are not set correctly.  When I got my used 20" grizzly, the knives were set too low in relation to feed rollers and it sniped all over.  Is that the tailing end of board?
Woodmizer LT15
Kubota Grand L4200
Stihl 025, MS261 and MS362
2017 F350 Diesel 4WD
Kawasaki Mule 4010
1998 Dodge 3500 Flatbed

YellowHammer

Does that happen on the outfeed, as the trailing edge of th aboard is exiting the machine?  

If so, and if you have a pressure bar, the it is set way too high on that side, and needs to be adjusted.

Is designed to keep exactly that from happening as it is set only a couple thousandths off an inch above the board and is a positive stop to keep the cutter from digging in like that.

You also may have a broken or mis adjusted outfeed roller down pressure spring on that side.  
YellowHammerisms:

Take steps to save steps.

If it won't roll, its not a log; it's still a tree.  Sawmills cut logs, not trees.

Kiln drying wood: When the cookies are burned, they're burned, and you can't fix them.

Sawing is fun for the first couple million boards.

Be smarter than the sawdust

Walnut Beast

What I was told by a designer is that if that board isn't flat that can also effect things. Like if the board had a twist to it

Tom King

You're going to need a dial indicator and holder to check every part and set to the correct specs, like the pressure bar, knife projection, etc., etc.

You can probably find the specs online, or on the old iron forums.

JRWoodchuck

The knives are ground in place so I'd like to think they're not the problem. Pressure bar sounds like a real potential. Seem like both sides the out feed roller springs are good but I'll check to make sure. These boards did happen to have a little cup they were only 5/16 and 20" wide so that could have a little to do with it but the pressure bar would resolve that I think.  I'll look up what the tolerances should be on that machine and get it dialed in. Thanks everybody!
Home built bandsaw mill still trying find the owners manual!

Don P

I was gonna ask if there was a pitch blob or flat field mouse that keeps coming around on a billy roll but you dropped them.
Does it correspond to the end of the board dropping off a table or bumping into an outfeed roller.

I looked at my tail man on the planer in the cabinet shop and he was drumming his fingers on the board to the music in his Walkman. Nothing like that heavy bite but it was Stairway to freebird etched in oak  ::). If the board is banging or dropping, it can make it bite.

YellowHammer

The pressure bar should be adjusted only about a thickness of paint above the outfeed board.  It's intended to not touch the board at all until it exits the front pressure roller, then the board end will cantilever up until it hits the pressure bar which now acts like a down pressure rub bar which keeps it from digging into the cutter head.  The snipe in the end of the board is a function of how high the pressure bar is set, and how much the board can jack up into the cutter before the pressure bar stops its lift.

Another good way to troubleshoot a planer is to put the sniped board back into the planer of course turned off, and drop the cutter head until it mates with the gouge and see what roller, support, etc would have let the board come up too high into the cutter head.  
YellowHammerisms:

Take steps to save steps.

If it won't roll, its not a log; it's still a tree.  Sawmills cut logs, not trees.

Kiln drying wood: When the cookies are burned, they're burned, and you can't fix them.

Sawing is fun for the first couple million boards.

Be smarter than the sawdust

trimguy

I get snipe on the tail end of my boards sometimes and after this conversation I believe my pressure bar is set to high. I'll have to check that. Woodchuck, if you find the adjustments tolerances for your machine I would be interested in a link. I have the same machine. Thanks.

Tom King

You can usually find copies of manuals on ebay, and sometimes even originals.

azmtnman

1983 LT 30, 1990 Kubota L3750DT, 2006 Polaris 500 EFI, '03 Dodge D2500 Cummins powered 4X4 long-bed crew cab, 1961 Ford backhoe, Stihl MS250, MS311 and MS661--I cut trees for my boss who was a Jewish carpenter!

trimguy

Thanks , I downloaded it and will look at it later.

YellowHammer

Here's the section on the pressure bar.

Basically zero+ clearance (same arc as the butterhead) on the board as it's running, and also tells how to adjust pressure bar spring pressure.



 
YellowHammerisms:

Take steps to save steps.

If it won't roll, its not a log; it's still a tree.  Sawmills cut logs, not trees.

Kiln drying wood: When the cookies are burned, they're burned, and you can't fix them.

Sawing is fun for the first couple million boards.

Be smarter than the sawdust

JRWoodchuck

Thanks for digging that up AZ. And thanks everybody else for the help going to dive into it when I've got a moment. 
Home built bandsaw mill still trying find the owners manual!

Don P

Butterhead: a correctly sharpened set of knives
                2) a term of endearment


Often enough a bright light, some prying and a blow nozzle can identify a culprit as well.

trimguy

I got a chance to do some adjustments on my planer. I set my pressure bar 10 thousandths of an inch higher than my blades. That is probably a little bit high, but I want to check that before I lower it anymore. I will do that the next time I fire up the generator. When I started it was almost 1/8 of an inch high, so I'm sure that was causing my problem. Woodchuck do you have any problems with your bed getting out of alignment from side to side. Thank you everyone for your help.

YellowHammer

1/8" ?  Whowsers, that's high.  Definitely a problem.  Don't forget to adjust the pressure bar springs, as well.
YellowHammerisms:

Take steps to save steps.

If it won't roll, its not a log; it's still a tree.  Sawmills cut logs, not trees.

Kiln drying wood: When the cookies are burned, they're burned, and you can't fix them.

Sawing is fun for the first couple million boards.

Be smarter than the sawdust

trimguy

Yes, I adjusted them as much as I moved the bar. They probably aren't right either , guess I'll have to do some reading.

trimguy

Update : 
 I had a chance to run several boards threw my planner, my snip was almost gone. I still have a little bit at the tail end which could easily be sanded out. I'm sure that's because when I set the pressure bar I set it a little high, I guess I'll have to move it down to the right clearance.  Thanks.

Don P

That little snipe at the end is hard to get rid of 100%. If possible make it the trim, I needed 8' for the porch floor at work, I was rough blanking stock for the planer at 104". Butt feeding helps considerably but if it is a bowed stick there will probably be some amount of snipe when it leaves the front feed roller.

trimguy

" butt feeding " I understand that to mean butting the next board to the one that is going through the planner. Is that correct ?

Walnut Beast

Did your try running another board directly behind the one going through. Do that. 

trimguy

I did not , feed and catch. I have a table in the works that will allow me to do that.

Don P

Quote from: trimguy on December 19, 2022, 03:03:45 PM
" butt feeding " I understand that to mean butting the next board to the one that is going through the planner. Is that correct ?
My boss is a jerk and I try to compliment anyway  :D but yes it helps to feed the boards end to end. The front of the back board helps keep the back of the front board down, a little.

If you feed and catch, notice the snipe difference if you let the board drop slightly vs if you lift the tail end slightly as the board exits.

YellowHammer

For the remaining snipe, there are a couple things to adjust.

If you have the rear feed roller adjusted too high, or set high for rough sawn wood, then it can "teeter" on that, because the board isn't sitting on the bed, it's on the roller and when it exits the front roller, the edge of the board drops the 5 or 10 thousandths to the planer bed and has the effect of making it instantly "thinner" by that distance.  To see if the rollers are causing the problem, drop them completely to the bed so the entire board is fully supported across the bed.  There should be no snipe on the front or back of the board.

If you are seeing no snipe on the back (or front) of the board, then the front or rear bed rollers are set too high.  Set too low and rough sawn wood has trouble feeding but set too high, finished wood will snipe.  So that's what many planers will have adjustable bed rollers.

If you are still seeing snipe on the end of the board with the bed roller down into the bed, then the pressure bar is still too high, or the pressure bar springs are set too loose, or the rear feed roller springs are set too light.  The most accurate way to set the pressure bar is with a bridging dial indicator gauge, but another good way to do it is by dropping the pressure bar a tad and feed a planed board.  As soon as the pressure bar is set just too low, the board will contact it and stop feeding.  So adjust the screws until the board just, and I mean just, passes under the bar on both sides.  That will mean the board has no room to jack up when it leaves the front pressure roller and there won't be any snipe, except if the pressure bar springs or feed roller springs are set too weak for the weight of the wood.

Basically, as the wood cantilevers out from the end of the bed, the planer supports it, but in actuality, it is being supported by the triangle of the the rear bed, the rear doewn pressure or feed roller which also has springs on it, and pressure bar with springs on it.  When you hold or support the end of the board with you and and the snipe lessons then it means that one of these sets of springs are set too soft and can't support the weight of the board as it cantilevers out from the rear of the planer, as long as the bed rollers are submerged into the bed. So adjust them to specs first and see what happens.  That should minimize the end snipe.  However, to fine tune it, tighten each spring a little and observe the difference.  Sometimes one side of the planer will have a different magnitude of snipe, so figure out why that is happening to get the worse side adjusted better.

Hope this helps.

       
YellowHammerisms:

Take steps to save steps.

If it won't roll, its not a log; it's still a tree.  Sawmills cut logs, not trees.

Kiln drying wood: When the cookies are burned, they're burned, and you can't fix them.

Sawing is fun for the first couple million boards.

Be smarter than the sawdust