Orbital Mechanism; Blade Movement; Orbital Position Selection - Hitachi CJ 120V Technical Data And Service Manual

7. ORBITAL MECHANISM

7-1. Blade Movement

In the Models CJ 120V and CJ 120VA, the orbital mechanism moves the blade up-and-down and forward-and-
backward in the same manner as the Models CJ 110V and 110 VA. This makes the blade dig well into wood and
other soft materials and also discharges cutting chips well to achieve speedy cutting. The amount of fore-and-aft
blade movement can be adjusted just by turning the change knob to any of the four settings. The following table
shows the modeled orbits of blade movement at each orbital position (change knob position).
2.3 mm (3/32")
(At guide roller position)

7-2. Orbital Position Selection

Selection of the most appropriate orbital position for each cutting job is essential to achieve the best efficiency for
cutting. However, as the best orbital position depends on such factors as the hardness and thickness of the
workpiece, the desired finish of the cut surface, and so on, it is not practical to set a single, simple standard for
best orbital position selection. Table 2 can be used as a general guide for appropriate orbital position selection
based on various factors.
Factor
Material hardness
Material thickness
Cutting speed
Straight cutting or
curved cutting
Surface finishing
Material stability
Table 1 Blade movement illustration
Table 2 General guide for appropriate orbital position selection
Soft material
Thick
Faster cutting
Straight cutting
Rough finish acceptable
(splintering, chipping acceptable)
Unstable
1.4 mm
(1/16")
Orbital position
0.5 mm
Perpendicular
(1/48")
movement only
Hard material
Thin
Slower cutting
Curved cutting
Fine finishing
Very stable