Hyd-Mech H-40, Operation And Maintenance Manual

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Pg 2.8
H40
Optimum blade speed curves.
STEP 3
DETERMINE OPTIMUM BLADE SPEED, V (ft/min)
The relationship between optimum blade speed and effective material width for various materials is
represented on the graph .
The graph shows that as effective material width gets wider or as material gets harder, lower blade
speeds are recommended. If material is narrower or soft, higher blades speeds should be selected.
NOTE: Higher than optimum blade speed will cause rapid blade dulling. Lower than optimum blade speeds
reduce cutting rates proportionately and do not result in significantly longer blade life except where there is a
vibration problem. If the blade vibrates appreciably at optimum speed as most often occurs with structruals and
bundles, a lower blade speed may reduce vibration and prevent premature blade failure.
NOTE: About Material Hardness
The Graph - Step 4, illustrates blade speed curves for material hardness 20 Rc (225 Bhn) or lower. If the
material is harder, use multipliers from the NOTE (near the bottom) of the Graph.
For example, if the 5" diameter, 1045 Carbon Steel material, from the table above, had been hardened to 35
Rc (325 Bhn) then we must multiply the blade speed of 225 ft/min by .60.