Tc 9-524 fundamentals of machine tools

6-13

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TC 9-524
Vertical Machine Feeds
With vertical machines, the feed is the pressure applied to
the saw blade by the material being cut. The workpiece may
be hand fed or power fed depending upon the operation to be
performed. Cutting curves or special contours requires that
the workpiece be guided and fed into the saw blade by hand.
The power feed on bandsaw machines is operated by
adjustable weights in the machine pedestal. The weights are
connected by cables to one of the work-holding attachments
of the sawing machine to pull the workpiece against the
bandsaw blade. To operate the power feed, the weights are
raised by depressing a pedal and the cables are then fixed to
the work-holding attachment. When the pedal is released the
weights pull the piece into the blade.
The following general rules apply to feeding workpieces on
bandsawing machines:
The feed should be light when starting a cut. The
pressure can be increased after the cut is established.
Hard materials require lighter feeds than softer materials.
Wider band saw blades will stand greater pressure than
narrow blades and can therefore be used with heavier
feeds.
When hard spots in the material being cut are
encountered, reduce the feed until the spots are cut
through.
Use a light feed when cutting curves;
straight-line cutting.
COOLANTS
Most sawing machines used in military
a heavier feed for
operations are dry
cutting machines; that is, they are not intended for use with
liquid coolants.
However, some power hacksaws and
horizontal bandsaws are equipped with a coolant attachment.
Soluble oil products, when mixed with water to form
emulsions, are used for these machines. This type of coolant
has proven very satisfactory for sawing where cooling is an
important factor. Most manufacturers of water oil emulsion
coolants add a rust inhibitor to the solution to prevent rusting
caused by the water in the coolant.