Chiseling Performance Comparison; Comparison Of Drilling Speed Change By Pushing Force - Hitachi DH 40MR Technical And Service Manual

6-3. Chiseling Performance Comparison

Chiseling performance varies considerably depending on the work conditions. Use the factory test results shown
in Fig. 2 for comparison purposes only.
(Note) B's chiseling amount is greater than the others because the circuit is controlled to make the number of
hammering in the "Hammering only" mode higher than that in the "Rotation + Hammering" mode.
However, B has inconveniences such as unbalanced hammering, heavy vibration, heavy tool shake,
and difficulty in positioning the tool because B increases only the number of hammering without
changing the weight of the striker (that is, hammering energy). The Model DH 40MR realizes self-
chiseling in addition to self-drilling (4-1-2. Self-drilling (Good feeling)).

6-4. Comparison of Drilling Speed Change by Pushing Force

The graph shown in Fig. 3 illustrates the relationship between handle pushing force and drilling speed.
DH 40MR: Tool shake is not heavy in whole range. Good feeling.
DH 40MA/DH 40 MB: Tool shakes heavily at pushing force 50 N.
B: Tool shakes heavily at pushing force 50 N and 75 N.
D: Tool shake is not heavy in whole range, but the drilling
speed is slow and the feeling is not good.
Pushing force (N)
Fig. 3
Fig. 2
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Pushing force