Why does jointing cause board to wedge
pielikiepap
| Posted in General Discussion on
When I joint a board to flatten one side I invariably end up with a piece that is significantly wedged at one end.It seems that the leading edge of the board is the end that is thinner than the trailing end after jointing. I just jointed a 2’x6” x2″ board and after removing the cupped surface it was 1.5″ on one end and 1″ on the other. This is also true for edge jointing. Jointer seems aligned. Help. Thanks.
Replies
Several normal check points : the knives need to just proud of the outfeed table #1 make sure of that .
This will also tell you if only your outfeed table needs adjusting to match the knives .
Try using the TS for straightening the edge then run it over the jointer to get your edge . Are the knives sharp ? I would start there and see where that gets you .
good luck dusty
Probably the most common cause is having the outfeed table just a tad too low in relation to the knives. Try raising the outfeed table incrementally to see if it improves. If you get to the point where your planed piece "bumps" into the outfeed instead of riding onto it, you're too high. Alternatively, take a long straightedge and make sure that the infeed and outfeed tables are perfectly parallel. If the tail (the outside edge) of the infeed table is just a tad too low it can cause the taper you refer to.
David Ring
http://www.touchwood.co.il/?id=1&lang=e
Thanks. This was exactly the problem. Charles Neil at his website also helped in this.
The idea of bringing a piece from 2 inches thick down to 1.5 inches on one end and only 1 inch on the other in order to remove a twist is rather remarkable. This must be an extraordinarily twisted board over those 2 feet and quite valuable too.
check the setup again. check your technique. something seems to be out of whack. Once you have a piece flat, is it 100% to remain flat with one more pass?
Matt
Edited 12/14/2008 2:25 pm ET by MattInPA
The advise about checking the knifes/table is very valid. A jointer lacks a reference surface to keep opposing edges parallel. A table saw uses its fence to produce parallel edges. Even a perfectly adjusted jointer may produce non-parallel edges if multiple passes are necessary to remove concave/convex edges. Knowing this I rotate the stock end for end when taking multiple passes. The attached link also addresses jointer operation.
http://www.newwoodworker.com/basic/usejntr.html
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