Production > Jointers
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Jointers face or flatten
wood
and are used primarily to joint small pieces of material. The operator
passes stock over a cylindrical, multiple-knife cutter head, while keeping the
stock flush against a guide. The depth of the cut is achieved by adjusting
the front table. There are two types of jointers: hand-fed jointers with a horizontal
cutting head, and wood jointers with a vertical head.
Injuries can occur if
the operator's hands and fingers come in contact with the knives. This
can happen when the operator is jointing narrow lengths of stock, particularly
when not using a jig or other holding device. Injuries can occur
when the operator's fingers ride along the surface of the jointer while
feeding the wood. Also, stock may be accidentally kicked away, exposing the
operator's hands to the cutter head.
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Potential Hazard:
- Point of operation - Contact with the knives may occur, especially if a holding
device is not used.
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Possible Solutions:
Engineering Controls
For hand-fed jointers, horizontal head:
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Enclose cutter head with an automatic (spring-loaded,
self-enclosing) guard that exposes the
cutter head only when the stock is being fed.
The guard must automatically adjust to cover
the unused portion of the head, and it must
remain in contact with the material at all times [29
CFR 1910.213(j)(3)]. The figure at the right shows the
appropriate use of a self-adjusting guard.
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Adjust the cylindrical cutter head so that the
knife projects no more than 1/8 inch beyond the
cylindrical body of the head [29
CFR 1910.213(j)(1)].
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Adjust the cutter head so that the clearance
between the path of the knife projection and the
rear table is no more than 1/8 inch [29
CFR 1910.213(j)(2)].
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Keep the clearance between the table and the
head as small as possible [29
CFR 1910.213(j)(2)].
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Fig 1 -
Jointer with self-adjusting guard
 Fig
2 -
Jointer Blade
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For vertical head jointers:
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Completely enclose cutter head, except for slot
to apply the material for jointing. This guard can
be part of the local exhaust system.
Work Practices
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Use hold-down push blocks when jointing wood
narrower than 3 inches.
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As a general rule, never joint pieces of material
that are less than four times the width of the bed
opening.
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Potential Hazard:
- Kickbacks - Stock may be thrown back at the operator after being caught by the
knives. This also may expose the operator's hands to the knives.
Possible Solution:
Work Practices
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Avoid deep cuts. They increase the likelihood of
kickbacks and require a larger table opening.
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Potential Hazard:
- Flying chips
- The cutting action of the knives may throw
wood chips and splinters.
Possible Solutions:
Work Practices
- Check knives regularly for proper setting and
adjustment, but be sure to shut off the power first.
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