Jointer help

[GOVOLS]

Trying to surface joint some Hickory that I had sawed up after tornadic activity a few years ago. I am building farmhouse table.
When I joint the lumber I am getting a taper across the width of the boards.
I started out with two inch material and now I have 1 3/4 on one side and much less on the other. I had to do multiple passes to get a bow out.
Any ideas why I'm seeing this taper.


Thanks

[JGrout]

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When I joint the lumber I am getting a taper across the width of the boards.

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your knives are not parallel to the outfeed table

Or your lumber is twisted and you are rolling it as you surface it

[tomsteve]

isnt jointing for flattening one side and planing for paralelling up both faces?
if so wouldn it be necessary to plane it to get everything the same thickness?

[JGrout]

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isnt jointing for flattening one side and planing for paralelling up both faces?

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using a jointer to flatten a reference face is done so you can create a parallel surface on the other face. even though it is done with a lot of frequency in small shops it is not technically a correct way to create true parallel surfaces

Jointing technically (actually edge jointing) is the action that creates a straight edge that is perpendicular to the reference face done in the first step

[Axl]

JGrout said:

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your knives are not parallel to the outfeed table

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I'm betting this is it. Check the knife heights end to end with a ruler placed on the out-feed table.

[MichaelMouse]

Sight the board, put it on a flat surface, rock and and determine the high side/points. Use your hold downs over the high points and let the low ones pass unjointed. In short, use it as what it is, a motorized plane. You can actually thickness with it, but you have to get a plane surface, scribe, and use differential pressure to remove stock to the line as if you were working a hand plane. Royal PITA. Old boys didn't worry overly much, as most boards had a "fit" or "view" side and a who cares side. You could plan your work to do this if you want, and the project allows.

[rayknight]

You need to plan your first cuts or you can easily make a wedge. If you start with a convex (bowed out) edge and align the front of the board to the table you WILL get a wedge, either joint the other side (which will usually be concave (bowed in), or on the convex side, take deliberate slices of the bowed out middle, until you have a flat to register to the table. To avoid this hand skill requiring step, I usually do the concave side first, nibbling at each end until it is close. Hope this makes sense. Ray

[mound]

JGrout said:

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using a jointer to flatten a reference face is done so you can create a parallel surface on the other face. even though it is done with a lot of frequency in small shops it is not technically a correct way to create true parallel surfaces

Jointing technically (actually edge jointing) is the action that creates a straight edge that is perpendicular to the reference face done in the first step

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I'm confused by this. What then is the technically correct way to create true parallel surfaces?

[rayknight]

For flat face parallel, joint one surface, use planer to thickness and consistent parallel other surface
For edge, joint one edge (at right angle to face), rip other edge (on tables) for parallel consistent width.

[JGrout]

surface a face on the jointer to bring it to flat and true with no twist, bring the opposite face parallel in the planer

That is not confusing that is the way it is supposed to happen

people who use planers to flatten stock are only getting there because the stock is already mostly flat or spend time fiddling around with sleds that work to something less than a stellar degree


Now I will take a bunch of fudge for stating the correct way to do the job..