HELP! Jointer has started to taper boards

[forrestb]

Well, with all the appreciated input:

1) once the board leading edge has passed the cutters the pressure is on the out feed table just beyond the cutters as much as possible. The trailing push pad is trying to just push forward not down even thought that is not truly possible. I have been jointing that way for many years and have NEVER observed a taper.

2) I have in the past kept pressure over the cutters when edge jointing to get a slight concavity. So I have experienced downward pressure location affects.

3) the 2nd board that tapered was measured with no taper end to end but I managed to taper it even using the hand-over-hand method to keep the pressure where it belongs.

4) and, no, I do not try to use the jointer to get 2 sides parallel.

So I can only explain this event by some kind of brain upset that has caused me to forget how to joint.

I have jointed all boards to get one side flat even though there may be a taper. I have thickness planed them to almost final and they are now resting for a few days.

I have been fortunate that I had boards thick enough to do the above. I will worry about boards closer to final thickness that need to have one side flattened in the future.

This is the first time that I have tried to joint true quarter sawn hard maple, but I cannot see how that would cause this problem.

Forrest

[charlese]

Hard maple is indeed, hard. The only thing I can think of, after reading your correct procedure, is your blades have dulled. A dull blade will cut deeper into the wood and requires more pressure on the outfeed table to overcome. If the problem gets worse I will know it's the blades fault, not your technique in feeding.

Try a piece of pine. If it is straight, then again, it's probably the blades.

Just thought of another cause - If the bearings on the cutter head have become worn, maybe the cutter head can lift (caused by the digging of the blades) a little.

This digging of a blade into wood is not understood by many woodworkers. I had to learn the hard way. This is the same effect of a router bit being loose in a chuck. It will dig deeper.

[benush26]

As I keep reading this the cobwebs in the oldest part of my brain keep on clearing out while I remember a lesson I was given about using the jointer on very hard woods and it had to do with never cut into the grain but always away from the grain. I remember be cause he treated me like I was 5 or 6 and the importance of grain flowing downhill left to right NEVER right to left . He took a really nice piece of teak (I think? Dang that was a while back!!), used his trusty scribe to draw on the side of the board so I could see the flow of the grain and then horror of horrors did it backwards. Three passes later it looked tapered. Something about going against the grain causing more tear out that gets worse with each pass?? I just know that now I always look for the grain running down hill and put it to my right.

Whether what I remember and what is happening here are at all the same I could not tell you, however the taper story did jog my old fart brain! Also brought back some great memories, so thank you for that!

Be well,
Ben

[JPG]

I have been away for a few hours and not getting to this 'discussion'.

I have already stated the technique and proper blade height(= outfeed height).

There are other factors to consider(the workpiece).

I agree with the comments linked to by algale, but have to disagree with his misquoting it. A workpiece having 'wavey' edge will not cause 'taper'.

However the shape as it rests on the infeed table will.

If the workpiece is concave upward, the trailing end of the workpiece will be raised above the infeed table. As the workpiece is advanced over the cutters and onto the outfeed table, the trailing end will continue to be 'high'. The end result(assuming correct technique) will cause the leading end to be cut more than the trailing end(the trailing end may possibly not have any material removed).

If the workpiece is concave downward, the middle may not have material removed and the result is what appears to be a 'double' taper.(wider middle)

The original post had nothing to do with 'parallel' sides/edges.

As for the grain direction, it is preferable to ALWAYS go with the grain when possible. That is the grain slopes down towards the trailing end.

[forrestb]

As I keep reading this the cobwebs in the oldest part of my brain keep on clearing out while I remember a lesson I was given about using the jointer on very hard woods and it had to do with never cut into the grain but always away from the grain. I remember be cause he treated me like I was 5 or 6 and the importance of grain flowing downhill left to right NEVER right to left . He took a really nice piece of teak (I think? Dang that was a while back!!), used his trusty scribe to draw on the side of the board so I could see the flow of the grain and then horror of horrors did it backwards. Three passes later it looked tapered. Something about going against the grain causing more tear out that gets worse with each pass?? I just know that now I always look for the grain running down hill and put it to my right.

Whether what I remember and what is happening here are at all the same I could not tell you, however the taper story did jog my old fart brain! Also brought back some great memories, so thank you for that!

Be well,
Ben

Thank you Ben, for the most relevant point. I did not see any tear-out and it is very difficult to see grain direction in true quarter sawn wood. You are looking at the flat grain on the edge and not much of it.

I might well have experienced that affect and could be that the pieces that DID NOT taper were, in fact, done with the grain and that the ones that DID taper were against the grain.

I feel better and now know what to look for in the future. My mystery is how to 'read' the grain in true quarter sawn wood.

Maybe measure thickness, make a pass, and see if you have taper????

Forrest

[JPG]

I would be looking at the grain on the wide sides. Are you 'face' jointing them?

[forrestb]

I would be looking at the grain on the wide sides. Are you 'face' jointing them?

I am face jointing the boards.

Here are pix showing grain patterns on face and on edge.

End.jpg (325.04 KiB) Viewed 2950 times

Edge.jpg (169.97 KiB) Viewed 2950 times

Based on Ben's comment I think that I have to learn to better read the edge for grain pattern.

Forrest

[JPG]

I would be looking at the grain on the wide sides. Are you 'face' jointing them?

I am face jointing the boards.

Here are pix showing grain patterns on face and on edge.

End.jpg

Edge.jpg

Based on Ben's comment I think that I have to learn to better read the edge for grain pattern.

Forrest

In that last pix, the left end of the board need be the leading end.

However the grain direction may vary over the entire length.

[forrestb]

I would be looking at the grain on the wide sides. Are you 'face' jointing them?

I am face jointing the boards.

Here are pix showing grain patterns on face and on edge.

End.jpg

Edge.jpg

Based on Ben's comment I think that I have to learn to better read the edge for grain pattern.

Forrest

In that last pix, the left end of the board need be the leading end.

However the grain direction may vary over the entire length.

Right on, JPG! That one was easy to read, I wish they all were. Grain direction change is very likely so I keep cuts to 1/32 or less.

Forrest

[beeg]

I would be looking at the grain on the wide sides. Are you 'face' jointing them?

I am face jointing the boards.

Here are pix showing grain patterns on face and on edge.

End.jpg

Edge.jpg

Based on Ben's comment I think that I have to learn to better read the edge for grain pattern.

Forrest

In that last pix, the left end of the board need be the leading end.

However the grain direction may vary over the entire length.

With that point in the grain, I'd try it the other way. The left end being the trailing end. A lot wood depend upon how the rest of the edge looks. Sometimes it's just a crap shoot to try one end, then the other end.