Board's jointed edge uneven

[greasemonkey2275]

You are not keeping the just planed edge tight to the OUT feed table.(assumes the blade height coincides with the outfeed table height). Once there is sufficient 'new' surface to assure alignment to the outfeed table, NO downward pressure should be exerted towards the infeed table.

Also the tables need to be 'coplaner'. Raise the infeed table until it is the same height as the outfeed table. A straight edge should touch all points on both tables regardless of it's position. The blades should 'just touch' that straight edge at their highest point.

When a workpiece is initially held tight to the IN feed table, the freshly cut end of the workpiece should just barely clear the leading edge of the OUT feed table and not rise above the OUT feed table as the workpiece moves forward. Once downward pressure is being applied to the OUT feed end, the trailing edge may properly ride above the IN feed table. If the workpiece is then forced down tight to the IN feed table the rocking chair rocker bottom effect will take place.

I zeroed out the tables, laid a straightedge across them and there is less than .010" between the blade and the straightedge at the blades closest point. I am going to try keeping pressure on the outfeed side and see if that works.

[jsburger]

It looks to me that the problem might be technique. Your board is longer then the in feed table. If the board edge is concave to start the tail end of the board will rise as you feed it until the end is on the table. You may have to make more than one pass to get it straight.

The most important thing when jointing is proper hand pressure on the stock. Obviously when you start the pressure is on the in feed table. Once you get a couple of inches of stock on the out feed table you should switch hand pressure to the out feed table since that is now the reference surface. You should only push with your in feed hand.

I always joint the concave edge first because no matter how long the stock is you will always have two points in contact with the table. The convex side will only have one point of contact and can rock depending on hand pressure.

[jsburger]

Dang, JPG, you beat me to it again.

[JPG]

If the workpiece is initially concave, it may help the trim both ends with a short pass.

BTW 0.010" low is excessive. That will cause the leading end to run into the end of the outfeed table and require lifting the workpiece to get it up onto the outfeed table. This alters the cutting direction slightly and creates a snipe on the leading end and directs the cut deeper into the trailing end.

I think it is time to raise the blades.

[greasemonkey2275]

If the workpiece is initially concave, it may help the trim both ends with a short pass.

The piece started out roughsawn and was fairly straight until I started jointing it and ended up with it being concave.

[JPG]

If the workpiece is initially concave, it may help the trim both ends with a short pass.

The piece started out roughsawn and was fairly straight until I started jointing it and ended up with it being concave.

Read the 'BTW' two posts back.

[greasemonkey2275]

If the workpiece is initially concave, it may help the trim both ends with a short pass.

The piece started out roughsawn and was fairly straight until I started jointing it and ended up with it being concave.

Read the 'BTW' two posts back.

I saw it and I'm getting ready to go make the adjustments.

[greasemonkey2275]

BTW 0.010" low is excessive. That will cause the leading end to run into the end of the outfeed table and require lifting the workpiece to get it up onto the outfeed table. This alters the cutting direction slightly and creates a snipe on the leading end and directs the cut deeper into the trailing end.

I think it is time to raise the blades.

I just finished bringing the blades up to where they just barely moved my machinists square and planed the board again. The entire length is now true; chalk another one up to user error. Thanks boys!

[JPG]

de nada