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 reparing
boards with surfaces that are perfectly straight, flat, and square to
one another requires a combination of jointing and planing techniques. |
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BUSTING DOWN LUMBER
Start with thoroughly shop-dried stock. Measure and mark the parts of
your project on the boards. As you do, leave extra stock, making the
parts 1 to 2 inches longer and 1⁄2 to 1 inch wider than their final
dimensions.
Cut and rip
the boards, roughing out the parts.
Craftsmen refer to this
as "busting down" rough lumber, and it relieves stresses in the wood. As
the tree grows, it often buttresses itself against wind or gravity.
Drying
may create further
stress. These internal tensions remain until you release them by cutting
the wood apart. As they are released, the
wood moves
slightly. But
since you’ve cut the parts oversized, you have the extra stock needed to
true them.
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TRUING BOARDS
To true a rectangular board, first joint one face flat and true. Turn
the board so the true face is against the fence and joint an edge. Plane
the remaining face parallel to the jointed face, and
rip
the remaining edge
parallel to the jointed edge.
Traditionally, you're
supposed to true the last edge on the jointer. However, the jointer does
not cut one edge parallel to the other. If you finish with the
jointer, there is a chance you're board won't be precisely rectangular.
Additionally, today's line-up of high-quality
saw blades
make such a smooth cut (if your table saw is properly aligned) that you
may not need to joint the last edge. The saw marks will be no more
prominent than the jointer's mill marks and you can remove them with a
light
sanding
or
scraping.
How you finish the
last edge depends on how the board will be used. If it's more important
that the board be rectangular (edges and faces parallel, as in a table
apron or a drawer side), rip the last edge and call it quits. If it's
more important that the edges be true (such as boards you will glue
edge-to-edge to make a table top or wide panel), then joint the last
edge. If the edges must be true and the board as close to
rectangular as possible, rip the board to within 1/32 inch of the final
width, then remove the last 1/32 inch with the jointer. |
STRAIGHT AND TRUE |
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If the board is thick
enough that you can safely stand it on its edge or you have several
boards that you can stack together and stand them on their edges, you
can plane the work to its final width as you would when preparing square
stock. This will leave the board(s) straight, true, and precisely
rectangular. |
PREPARING BOARDS
1
Joint one face. |
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2
Joint one edge square to
jointed face. |
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3
Plane remaining face. |
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4
Rip or joint to width. Or rip to
within 1/32" of the desired width
and remove 1/32" with the jointer. |
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SQUARING STOCK
To true square stock,
joint two adjoining surfaces true and square to one another, as you do
when truing a rectangular board. Mark these two jointed faces (so you
remember which they are) and plane the remaining surfaces parallel to the
jointed surfaces. Plane both remaining surfaces with the same thickness
adjustment. The stock will be perfectly square. |
STRAIGHT, SQUARE,
AND TRUE |
PREPARING SQUARE STOCK
1 Joint one surface. |
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2 Joint an adjoining
surface
square to the first. |
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3
Mark the jointed surfaces.
Plane a remaining
surface. |
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4 Plane the final
surface. Do not
change thickness.
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PROBLEM |
POSSIBLE CAUSE |
SOLUTION |
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Jointer cuts a slightly bowed surface. |
Knives are too high or too low in
relation to outfeed table. |
Reset knives or adjust outfeed table. |
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Jointed surfaces are not square. |
Fence is not square to tables.
Knives are not parallel to table
surfaces. |
Reposition fence.
Reset knives. |
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Wood drifts to one side in planer. |
Feed roller pressure is uneven. |
Adjust roller pressure. |
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Wood thickness is not even. |
Planer knives are not parallel to bed. |
Reset knives. |
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Planer cuts snipe in ends of board. |
Feed roller pressure is too low.
Bed rollers are too high.
Long board is not properly supported. |
Increase roller pressure.
Lower bed rollers.
Support board with roller stand. |
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Machine bogs down, trips circuit
breaker. |
Depth of cut is too deep.
Feed
rate is too high. |
Reduce depth of cut.
Reduce feed rate. |
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Wood is difficult to feed, seems to
stick. |
Planer bed or jointer tables require
waxing.
Planer feed roller pressure is too
high.
Planer bed rollers are too low. |
Wax and buff bed or tables.
Reduce roller pressure.
Raise bed rollers. |
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Machine chips or tears wood grain. |
Knives are cutting against the grain.
Wood grain is figured.
Knives are dull. |
Reverse board end for end, or reduce
feed rate or depth of cut.
Reduce feed rate or depth of cut, or
rout and sand stock to thickness.
Touch up, sharpen, or replace knives. |
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Machine leaves noticeable mill
marks. |
Feed rate is too high.
One knife is set too high. |
Reduce feed rate.
Reset knife. |
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Machine leaves raised lines. |
Knives are nicked. |
Sharpen or replace knives. |
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