Jointer frustration

[Brian Penning]

Maybe I should call it Wood frustration?
Was jointing a 51" long 2" thick piece of maple on my jointer and I could feel and hear that the blades weren't always cutting the same as the previous pass. In fact it was as if I was cutting LESS wood than the previous pass.
Checked the tables and all OK. Only thing I can figure is that the wood was bowing as I was jointing it. Is that possible?
Sort of like when cutting a piece on the table saw and seeing it try and close behind the blade or move away from the fence.
I'm wondering if the same thing has happened to others.
TIA

[Darius Ferlas]

Yes, the same (and worse) happened to me. I have since worked out a few approaches/techniques.

First, if possible and practical I joint pieces that are thicker, a then using the jointed surfaces as reference I work on the other surfaces on my TS with a glue line blade. There is a risk that goes with it - after ripping some internal tensions may be released and the pieces will go whichever way they want. Sometimes is matters, sometimes it doesn't

If the above is not possible, then:

- I press the piece down on the infeed for about 1/4 to 1/3 length
- I shift the pressure on the outfeed, without any pressure before the cutter

Sometimes, no matter what I do the lumber will have the mind of its own though.

[Rod Sheridan]

Maybe I should call it Wood frustration?
Was jointing a 51" long 2" thick piece of maple on my jointer and I could feel and hear that the blades weren't always cutting the same as the previous pass. In fact it was as if I was cutting LESS wood than the previous pass.
Checked the tables and all OK. Only thing I can figure is that the wood was bowing as I was jointing it. Is that possible?
Sort of like when cutting a piece on the table saw and seeing it try and close behind the blade or move away from the fence.
I'm wondering if the same thing has happened to others.
TIA

If it's not technique related it could very well be internal stresses in the wood.

Sometimes those pieces of wood are reserved for special uses at my house, such as toasting marshmallows for the neighborhood kids.

Regards, Rod.

[glenn bradley]

Original non-flat faces and stress release movement during milling are what we are eliminating when jointing. If I find I have a batch of really lively material I will joint it once or twice and let it stand awhile before going on to the finished surface.

Variations in sound and feel will reflect the variations in the material as you are working it. If you are getting a lot of variation you may want to try letting it stand over night after a pass or two and see if it settles down.

Techniques vary but I keep my downward pressure on the outfeed table with just enough on the infeed table to get the material to move in a controlled manner.

[Don Morris]

If you're going right back to the jointer for that next pass, well cured Maple just doesn't have the reputation of having that much livlihood. At least I've not heard of that much with Maple, but I'm not "super" experienced with it. I sure would suspect my technique first. That can change from pass to pass unless I'm careful (that I know!). Also, make sure you don't reverse the direction of the pieces between passes. Reversing directions will produce different results between passes. Don't ask me how I know.

[Frank Drew]

Was jointing a 51" long 2" thick piece of maple on my jointer and I could feel and hear that the blades weren't always cutting the same as the previous pass. In fact it was as if I was cutting LESS wood than the previous pass.
Checked the tables and all OK. Only thing I can figure is that the wood was bowing as I was jointing it. Is that possible?


Brian,

Were you face jointing or edge jointing?

If this piece of material was wider than a 2x2 I'd be surprised if you could deflect it just with normal pressure while jointing, if that's what you meant.

I'd also be surprised if you'd jointed off enough to cause the wood itself to bow from one pass to the next.

Make sure the knives are even with each other and that at top dead center of the cutting circle they're even with the outfeed table; recheck the tables' for co-planarity.

[Prashun Patel]

When jointing light passes, I've never had it spring so bad that it varies from pass to pass. Usually, it'll joint or plane down perfectly, and then a couple minutes/hours later, it's not flat anymore.

If you are dead sure yr tables and blades are all perfect, I'm gonna guess there's something off in yr technique. Personally I find it hard to joint a board that tails off in one direction close to the end or highly warped boards. To compensate, I usually flip the board front to back on each pass. That usually gets it. I'll run the last pass or two in the direction that minimizes tearout.

You might also have better luck breaking down the piece into parts closer to yr final width and length (if u haven't already done that).

[Brian Penning]

Been going absolutely nuts with this problem and wasting some expensive wood too!
But I think I got it figured out.
I don't believe it's the wood after all since it keeps occurring when a piece is laid flat but not when edge jointing.
I recently had a heavy nick taken out of the blades about 2 inches from the blade ends.
The resulting ridge protruding from the wood would affect the next pass made. Not sure how exactly but it does.
Experimenting with narrower pieces jointed in the nick free area of the blades seems to bear this out.
This all make sense to anyone??

Part 2 is if I reposition the blades so the nick isn't all in the same line fix the problem?

Thanks for any and all replies.

[Mike Goetzke]

I think you should replace the blades first before something else happens.

Mike

[Mel Fulks]

When you have a nick in jointer knives it makes your out feed table too high.The material will climb and remove more wood at the beginning of the cut than at the end.When cutting an edge it is easy to avoid the gap by moving the fence;but what about facing ? For old big iron jointers there is an easy quick way to adjust out feed table up or down as needed.Add a table position indicator.Make a triangular sheet metal pointer and bolt onto machine with point on the outer edge of the adjustment wheel.Wrap the edge of the wheel with masking tape.Use a pen to make a mark on tape adjacent to pointer.Adjust in feed table level with out feed table.Turn out feed wheel,in up direction,one full turn.Measure how much out feed table is higher than in feed table.Measure the circumference of out feed wheel and do the math to determine increment mark spacing.On the last machine I did marks three eights of an inch apart represented table movement of two thousandths.Use dividers and file to mark permanent lines on the edge of the wheel.Put wheel back on in former position and lower one full turn PLUS and bring up to pen mark.Remove tape(except at original pen mark).Move fence to a sharp undamaged part of knives.Take two dressed boards three or four feet long and preferably at least six inches wide.Holding down on out feed side joint an edge of both.Put the edges together .If they touch along entire edge go buy a lottery ticket.If there is a gap in the middle lower table and joint them again.If they touch in the middle raise table a thousandth or so and joint again repeating process until they touch along entire length.Remove the rest of the tape and make a new mark on a small pc. Of tape at pointer position. This is your new home position for jointing edges.When you are facing and material is climbing because of knife gaps lower table a little .You will soon be able to guess pretty well how and when to make rapid adjustments.You usually need to"zero in" every time you change knives.Keep table slides sprayed with good lube.