Board rocking on jointer


MartinN

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Hi everyone, 

I just got my first (new to me) jointer.  I'm having a hard time getting boards flat with it (both faces and edges). 

I got the jointer from an auction at a cabinet maker that was closing down,  so I'm assuming the tables are co planer. (I don't have a 48 inch level to check but will get one if needed). 

I've watched the wood whisperer videos on setting up and using jointers and I'm not sure if this is a user issue or calibration issue.  

If I cut half way through a board while edge jointing I've noticed that there is significant play and the board will lift up off the indeed table  when you put pressure on the out feed table. I think that's why the  boards are ending up too thin on the front half and too thick on the back half. 

Any thoughts on what could be wrong? 

20151220_154521-1600x900.jpg

20151220_154457-1600x900.jpg

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1 hour ago, MartinN said:

f I cut half way through a board while edge jointing I've noticed that there is significant play and the board will lift up off the indeed table  when you put pressure on the out feed table. I think that's why the  boards are ending up too thin on the front half and too thick on the back half. 

This whole thing makes no sense. I have a feeling it's your technique. Lets start from scratch.

Face joint first- Make pencil lines on the face you intend to joint. Use push pads and apply more pressure on the outfeed side throughout entire cut. The trailing push pad should be less pressure, just enough to keep the board from hoping on the cutter. if you need to make an adjustment with push pads, make sure one is keeping pressure on the outfeed side just beyond the cutter. Try to keep the board moving through the entire cut. Use wax.

You know you're flat when the cutter is making contact with the face throughout the cut, and your pencil marks should be gone.

Edge joint- Put flat face aginst fence and repeat process the same way for the edge. I don't normally use push pads for edge jointing (unless it's a small piece) but use the same technique. 

Biggest thing to remember is having more pressure on outfeed side, just beyond the cutter.

 

If you edge joint properly it makes no difference if the board is wider on one end or the other across the face (as I think you suggested). That's what the table saw is for, to make the edges parallel. 

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Sorry,  it was a little hard to explain.  I've attached a photo of what I mean by the board getting thinner on only one side. 

After 5 or 6 passes trying to face the  board - the edge on the left hand side is about 1/8 thicker then the edge on the right. 

After the Packers finish this horrible display against the Raiders I'll see if I can find a way to take a video that doesn't exceed the sites upload limits. 

20151220_154618-1600x900.jpg

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Okay, so the board thickness is changing over the length of the board. Forget that, it means nothing. If your board is like that from the start it will be like that after jointing. Be more concerned with the flatness of the face, not the thickness. Thats what a planer is for, to even that up. 

If all of the cutters are the same height as your outfeed (at top dead center) across the whole length of each knife, and your tables are flat and coplanar, and the board still rocks, then your technique is flawed. 

If you face joint a piece that is slightly shorter than your outfeed, it should lay flat on the outfeed table and not rock. If it does, you have a problem with one or the other...setup, or technique. If it lays flat, it doesn't matter the if the thickness changes, the planer will fix that. I would double check the setup, and a long strait edge is a must for this process. 

Taking small bites 1/32 +/- until you get used to the technique will help. And pencil marks will tell you a lot about what's happening.

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Sorry for breaking this into two videos...  I don't use the video recording feature on my phone much....

The board does not lay flat on the jointer's infeed  table.  When I run the board through the jointer you can feel the knives making contact with the wood for the first 4 or 5 inches but then once I shift to putting pressure on the out feed table the knives stop making contact with the wood. 

(Gah..  I hate looking at myself on video!) 

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Alright.  It seemed in my mind that one side getting thinner and one side not meant that it was not making a straight surface  but upon rereading Janelle's post I think I get it. 

Looks like it is time to order a long straight edge. 

Just to clarify  -  I was using the 2 x 4 as a practice piece because I managed to massacre some other wise good cherry earlier today.  

I have been having the same issue with facing,  so I haven't been able to get a flat face to register against the fence.  

I'll put a straight edge on order  and see if there is a significant sag on my infeed table, since it seems like that could cause this. 

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The jointer is doing exactly what it is supposed to be doing. It is making that edge straight which has nothing to do with parallel. Actually it is normal that it is making it unparallel with the other edge.

First thing, keep going untill the lines are all gone. Once the lines are gone, in theory the edge should be straight.

Second thing, put the calipers away!!

After that edge is straight, you rip it to width at the tablesaw to make it parallel.

Sent from my SGH-I337M using Tapatalk

Edit: And yes John is right, you should tackle the face first. Remember FEE faces, edges, ends.

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You're definitely not getting a proper jointed edge regardless of the width, if the pencil lines are on the trailing edge still. 

Again...It doesn't appear that you face jointed it first, which is crucial for a good edge joint. I can tell by the video it was't face jointed properly...or at all, because I can see space between the board and the fence. 

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24 minutes ago, Janello said:

You're definitely not getting a proper jointed edge regardless of the width, if the pencil lines are on the trailing edge still. 

Again...It doesn't appear that you face jointed it first, which is crucial for a good edge joint. I can tell by the video it was't face jointed properly...or at all, because I can see space between the board and the fence. 

I agree with the first comment but disagree with the second.

You should be able to get a STRAIGHT edge on that 2x4 regardless of whether or not you flattened a face first.  Getting it SQUARE to the face is another story.

I'm gonna say you have some coplanarity issues there since you're unable to remove the pencil marks along the entire edge, and I don't see any huge issues with your technique.

Get a good straight edge, some feeler gauges, and a whole bunch of xanax and spend a day trying to dial the tables in dead nuts.  After you've accomplished that part, we'll pick up where we left off.  No point running in circles trying to diagnose the problem when the tables haven't even been checked for coplanar.  That's like tearing down an engine that won't start before checking to see if it has gas in it.

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2 minutes ago, Eric. said:

I agree with the first comment but disagree with the second.

You should be able to get a STRAIGHT edge on that 2x4 regardless of whether or not you flattened a face first.  Getting it SQUARE to the face is another story.

THAT two by four could use some KISS clarification. That two by four is short enough for the same high points to register on the fence through the whole cut. A board that is longer might not fare so well. 

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2 hours ago, bgreenb said:

Sounds like table coplanarity to me. I would bet the far end of your outfeed table is lower than the cutter. That would make the trailing edge ride high over the cutter head. You need to go through the proper setup procedure. It sucks, but you (should) only have to do it once. 

This is what I would check first.

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