Using a Jointer
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The jointer is a machine for power planing stock on faces and edges. It is the first tool used to straighten a board by trueing one face and one edge, followed by using a thickness planer to make the board an even thickness, then the other edge is cut parallel with a table saw. The planing is done by a revolving cutterhead equipped with two or more knives. The size of a jointer is designated by the width, in inches, of the cutterhead. 
Shop and Compare The cutterhead cuts toward the infeed table; therefore, to cut with the grain, you must place the piece with the grain running toward the infeed table. A piece is edged by feeding it through on edge with one of the faces held against the fence. A piece is surfaced by feeding it through flat with one of the edges against the fence. However, this operation should, if possible, be limited to straightening the face of the stock. The fence can be set at 90° to produce squared faces and edges, or at any desired angle to produce beveled edges. The table consists of two parts on either side of the cutterhead. The stock is started on the infeed table and fed past the cutterhead onto the outfeed table. The surface of the outfeed table must be exactly level with the highest point reached by the knife edges. The surface of the infeed table is depressed below the surface of the outfeed table an amount equal to the desired depth of cut. The usual depth of cut is about 1/16 inch. The level of the outfeed table must be frequently checked to ensure the surface is exactly even with the highest point reached by the knife edges. If the outfeed table is too high, the cut will become progressively more shallow as the piece is fed through. If the outfeed table is too low, the piece will drop downward as its end leaves the infeed table, and the cut for the last inch or so will be too deep, causing what is referred to as snipe.  With a straight edge check that the infeed and outfeed tables are parallel to each other. To set the outfeed table to the correct height, first feed a piece of waste stock past the cutterhead until a few inches of it lie on the outfeed table. Then, stop the machine and look under the outfeed end of the piece. If the outfeed table is too low, there will be a space between the surface of the table and the lower face of the piece. Raise the outfeed table until this space is eliminated. If no space appears, lower the outfeed table until a space does appear. Now, run the stock back through the machine. If there is still a space, raise the table just enough to eliminate it. Then as a check, edge join two pieces of stock and check for gaps by placing the jointed edges together. Parallelogram vrs. Dovetail A regular jointer table slides up and down on dovetail ways, think of it as one wedge sliding on top of another. If the table is not machined perfectly there is little you can do to put the tables back in parallel other than placing shims in between the wedges to lift up one side or the other. A parallelogram table sits on eccentric bushings that can be turned to raise or lower each table at any of four points giving you much better adjustment abilities if things aren't machined right to begin with. Sight down the board to determine the two low corners, mark these with an X, run the board part-way through from one end with the X down, turn end for end and run it part-way through with other X down. Sight the board and repeat until board appears to be straight, then run a pass all the way through.
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Delta Floor Model
Delta Bench Top Model
Replacement Blades
Push Blocks
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