Jet BD-11G Operating Manual page 16

Jaw teeth and scroll must always be fully engaged. Otherwise
chuck jaws may break and fly off in rotation (Fig 10-1).
Figure 10-1: Poor jaw engagements
Avoid long workpiece extensions. Parts may bend (Fig 10-2)
or fly off (Fig 10-3). Use tailstock or rest to support.
Figure 10-2: Workpiece too long
Figure 10-3: Workpiece too long
Avoid short clamping contact (A, Fig 10-4) or clamping on a
minor diameter (B). Face locate workpiece for added support
Figure 10-4: Poor clamping
10.3 Cutting Tool Setup
The cutting angle is correct when the cutting edge is in line
with the centre axis of the work piece. Use the point of the
tailstock centre as a gauge and shims under the tool to obtain
the correct centre height (Fig 10-5).
Figure 10-5: Cutting tool setup
Use a minimum of two screws to clamp the cutting tool.
Avoid large tool extensions.
10.4 Recommended spindle speeds
ATTENTION:
Generally speaking, the smaller the cut diameter, the greater the
RPM required. Soft materials require higher speeds; hard metals
slower speeds.
Metal is usually machined with coolant or cutting oil applied.
Recommended spindle speeds for cutting 10mm diameter,
with HSS tools (High speed steel tools):
Plastic: ................................................................. 2000 /min
Aluminium:.......................................................... 2000 /min
Brass: ................................................................... 1000 /min
Cast iron:............................................................. 1000 /min
Mild steel:.............................................................. 800 /min
High carbon steel:................................................. 600 /min
Stainless steel:....................................................... 300 /min
For carbide tools (HM), 5 times higher speeds can be chosen.
For example:
Turning mild steel at a diameter of 20mm allows
With HSS tool......................................................... 400 /min
With carbide tool................................................. 2000 /min
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