Makita UC4050A, UC4550A Sharpening the saw chain, Sharpen the saw chain when, Sharpening criteria

Sharpening the saw chain

CAUTION:

•Always withdraw the mains plug and wear safety gloves when performing work on the saw chain.

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Sharpen the saw chain when:

−Mealy sawdust is produced when damp wood is cut;

−The chain penetrates the wood with difficulty, even when heavy pressure is applied;

−The cutting edge is obviously damaged;

−The saw pulls to the left or right in the wood. The reason for this behavior is uneven sharpening of

the saw chain, or damage to one side only.

Sharpen the saw chain frequently, but remove only a little material each time.

Two or three strokes with a file are usually sufficient for routine resharpening. When the saw chain has been resharpened several times, have it sharpened in MAKITA authorized service center.

Sharpening criteria:

− All cutter length must be equal. Cutters of differing
length prevent the chain from running smoothly,
and may cause the chain to break.
− Do not sharpen the chain once a minimum cutter
length of 3 mm has been reached. A new chain
must then be fitted.
− The chip thickness is determined by the distance
between the depth gauge (round nose) and the
cutting edge.
− The best cutting results are obtained with following
distance between cutting edge and depth gauge.
	Chain blade 91PX: 0.65 mm
1	2	1	2	1. Cutting length
				2. Distance between
				cutting edge and
				depth gauge
				3. Minimum 3 mm
3	1
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WARNING:

•An excessive distance increases the risk of kick-back. − The sharpening angle of 30 ° must be the same on all cutters. Differences in angle cause the chain to run roughly and unevenly, accelerate wear, and

lead to chain breaks.

− The side plate angle of the cutter is determined by the depth of penetration of the round file. If the specified file is used properly, the correct side plate angle is produced automatically.

− Side plate angle for each saw chain are as follows: Chain blade 91PX: 80 °

1.Side plate angle

	30
30
1	1
014455

File and file guiding

−Use a special round file (optional accessory) for saw chains to sharpen the chain. Normal round files are not suitable.

−Diameter of the round file for each saw chain is as follows:

Chain blade 91PX: 4.0 mm

−The file should only engage the cutter on the forward stroke. Lift the file off the cutter on the return stroke.

−Sharpen the shortest cutter first. Then the length of this shortest cutter becomes the standard for all other cutters on the saw chain.

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−Guide the file as shown in the figure.

−The file can be guided more easily if a file holder (optional accessory) is employed. The file holder has markings for the correct sharpening angle of 30 ° (align the markings parallel to the saw chain) and limits the depth of penetration (to 4/5 of the file diameter).

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