Makita UC4051A UC3551A UC4051A Instruction Manual - Page 16

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 Authorized or Factory Service Centers. 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 (0.025") 2 1 2 1 1. Cutting length 2. Distance between cutting edge and depth gauge 3. Minimum 3 mm 3 1 014456 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 (11/64") − 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. 006927 − 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). 30 006928 − After sharpening the chain, check the height of the depth gauge using the chain gauge tool (optional accessory). 16