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A Jointer, also called a planer, is a power
tool used to render a wooded piece with a flat surface. Usually, a
jointer is used to plane the edges of two boards, before they are to be
joined together. The tool can also be used to provide rough wood with a
smooth finish, or narrow down a wooden piece. This is a useful tool in
woodworking, as wood is a material that may expand, contract, or warp
in different seasons, and therefore may need to be reshaped. Wood as a
raw material is normally rough and uneven and needs to be shaped before
it is used for making furniture and other wooden items. A jointer can
quickly cut and scrape the wood into the desired specifications, a task
that would take a much longer time if performed manually. The jointer
is often seen in carpentry workshops and can be used by both
professional as well as non-professional operators.
Features and working of a jointer
The jointer consists of two tables, placed
along the same horizontal plane, forming the infeed and Outfeed
portions. The cutting apparatus, called the cutterhead, consists of a
set of sharp blades, located between the two tables, which initiate the
cutting action through their rotational motion. Most often, the number
of blades used is around 3, having an approximate diameter of 3 to 4
inches. The wooden piece to be jointed is pushed along the infeed
table towards the outfeed table, with the required amount of material
getting cut when the piece passes over the blades. Depending on the
application, the height of either of the two tables can be changed. The
table adjustment handwheels are front mounted for easy access. The
tables are often mounted on a cast-iron wedge bed for better stability.
Gibbed dovetailed ways, on which the tables operate, minimize wear and
tear. The table is generally precision-machined for added accuracy,
with a built-in rabbeting ledge.
The movement of the blades is powered by an
approximately 3 HP induction motor, generating a cutterhead speed of
around 7000 revolutions per minute (rpm), with a capacity of around
17000 cuts per minute. The operational speed can be adjusted for fast
cutting and a smoother finish. For added durability and power, the
motor is often enclosed in a steel stand. A hinged door provides access
to the motor and the V-belts for any service or maintenance.
A movable Fence is fixed to the tool which
can be placed at different angles. Generally, the fence is placed at a
90 degree angle to get Square or rectangular cuts and at some other
angle to create beveled edges. A convenient handwheel allows the user
to tilt the fence at any chosen angle, with built-in positive stops at
45 and 90 degrees. The part of the fence in contact with the table has
a non-mar coating to prevent scarring of the workpiece. The fence is
usually center mounted for added versatility. A rack and pinion design
enhances the fence adjustment precision.
Some jointers have a parallelogram design to
minimize the distance between the table and the cutterhead and also
quicken adjusting the depth of cut. This design ensures that the
parallel orientation of the table is maintained over a long period of
time. The table area is approximately 8 x 82 inches. A 1/8 depth
limiter control knob, which can be disabled, eases any adjustments to
be made.
What to look for in a jointer
An auto-set quick change knife system eases
the task of changing the blades. As with any cutting tool, there is
bound to be a certain amount of dirt and sawdust being emitted. An
efficient dust collection system, with an approximately 5 inch outlet
for dust and chips, provides a clean environment for the operator as
well as prevents dust from entering the internal parts of the machine
and damaging the components therein. An ON/OFF paddle switch is placed
sufficiently above the table to provide enough space for working. An
infeed table positioning lever allows quick height adjustment.
The safety factor for the user is enhanced
with a cutterhead guard that covers the blades when the tool is not in
operation. Unauthorized tool use is avoided with the incorporation of a
toggle switch with a detachable key. The noise emitted from the tool
is minimized with an iron-serrated table rips that are ductile and
replaceable. Most of the internal moving parts of the tool are rendered
with ball bearings to prevent wear due to friction.
Some reputed
manufacturers of jointers include Delta, Jet, Powermatic, and TD
Industrial.
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