How do I remove bow from board using jointer?

[Chris Barnett]

If you posted at least your location, you might get an invite to a local woodworkers shop to learn how to do stuff. Without your location shown, folks just will not bother. And if you want to stay secret cause you worked for the company, that's ok too.

[Rick Moyer]

If you joint a board with the bow going up (frown), the board will gradually change its angle of attack as the tail end rides up onto the infeed table. This will result in a curved face. Jointing with the bow down (smile) allows the board to remain at what ever angle of attack you start the board in.

To get the most thickness out of a board without cutting it down to shorter lengths, your board should start out balanced on the crown of the bow. Your first pass will flatten the middle of the board. Each successive pass will lengthen the flattened area towards both ends of the board simultaneously.

In "theory" this approach may work, but I don't know anyone who does it this way. How can you possibly balance a four or eight foot board perfectly on the crown of the bow? The idea of face jointing is to use the outfeed table as a referenced flat surface, raised slightly above the infeed table, to remove a small thickness until flat. using the "frown" method, some of each end will be removed until the surface is flat, again referencing off the outfeed table. I believe your method could work, but only if you could maintain accurate balance, keep both ends exactly the same distance from the table, on every pass. Even then, you are not relying on the flatness of the table so much as you are relying on your ability to balance the board on the crown. May as well just hand plane it.

I would suggest to the OP that he do some research on using a jointer and draw his own conclusions on this advice. Don't mean to offend, but I wouldn't use your method.

[Gary McKown]

Totally agree with Rick. Besides, every successive pass on the Frown makes the board slightly more straight, as material is only being removed from the ends. The only time I would think about jointing the Smile is when only the end portions curl upwards and the middle is relatively straight.

[Greg Sznajdruk]

Scott:

If your a visual like me then this video may be of interest.

http://thewoodwhisperer.com/episode-...inters-jumpin/

Greg

[Mike Goetzke]

Scott - FYI I at times have trouble remembering these terms maybe this chart can be useful (I found this on-line):

[Myk Rian]

And if you get a board with a cup, twist, bow, and crook, (I have) throw it in the fire.

[Scott T Smith]

??? Not where I am. If it's rough and sold as 4/4, it has to be an honest 4/4. Most of the common domestic species are often sawn "heavy" and will actually measure an extra 1/16th. Walnut seems to be an exception, it's usually spot on. I believe most states weights and measures regulations cover this, and since so much lumber is shipped across state lines, there are federal laws or regs concerning it, also. Dimensioned lumber is another story.

Much confusion exists regarding rough sawn lumber due to the fact that some mills are referencing the sawn (green) thickness, and others the kiln dried thickness. To my knowledge, there is no national standard.

Shrinkage during the drying process is also not consistent; quartersawn boards lose more thickness than rift sawn, which affects actual thickness on green referenced boards.

[Dean Karavite]

Scott - FYI I at times have trouble remembering these terms maybe this chart can be useful (I found this on-line):

Thanks Mike, that's a great reference. One question, what do you do if you have a board that has all of these characteristics! :-)

[Kent A Bathurst]

Thanks Mike, that's a great reference. One question, what do you do if you have a board that has all of these characteristics! :-)

Checking - lose that end. With severe twist, cut board down to near target length. If this doesn't take care of those 2- firewood, and be more careful buying next time. For the others - crook out first on BS or on TS with sled. Then for bow + cup, joint it "horns down".

[james bell]

question to Robert Reese -

I like your idea of jointing both ends rather than the entire board which i have been doing. however thinking about it (which usually gets me into trouble), it would seem that the end not being initially jointed would ride higher on the infeed table, thus putting more of the jointed end in a 'downward' position. this would then take more off than necessary. if you reversed the sides each time, then that would correct this situation.

not sure i am explaining it well, but hopefully you get my drift.

any comments on this would be appreciated.

thanks ... jim