BANDSAW OPERATIONS - OD1646 - LESSON 1/TASK 1
(c) Blade Wear. Bandsaw blades become dull from prolonged use, but some
conditions promote greater than normal wear on the blades.
quickly if used at too high a speed for the material being cut. Also, if
the material to be cut is too hard for the pitch of the blade, abnormal wear
will result. This can be caused by hard spots in cast iron or welded metal,
and usually can be anticipated so that the operator can reduce the feed.
Rubber and some fibers or plastics contain abrasive material that will dull
saw blades regardless of the sawing speed and feed. Premature blade dulling
often occurs from using too fine a pitch blade and from feeding too quickly.
(d) Symptoms of Worn Blades.
Several symptoms appear when a bandsaw
blade is dull.
If the bandsaw blade cuts slowly or not at all when the
workpiece is fed by hand, the blade is probably dull. Blade teeth which are
bright on the cutting edge also indicate a dull blade. Another sign of a
dull blade is when it becomes difficult to follow a line or when the blade
forces to one side or the other. A dull blade is also indicated when the
chips from cutting metals are granular (except for cast iron which produces
granular chips with both sharp and dull blades). With the machine stopped,
or with the bandsaw blade removed from the machine, run a finger slowly over
the teeth in the cutting direction.
If sharp edges cannot be felt, the
blade is dull and should be replaced.
(2) Guide Selection. Standard saw guides are furnished with the bandsaw
machines and are designed to guide the saw blade to a constant location.
The standard guides are installed directly on the post and keeper block.
Adjustable saw guide inserts allow the guides to be adjusted to the size of
the saw blade to be used. Two special attachments, the angular blade guide
and the miter guide, provide added capabilities to the bandsaw machine.
(a) Adjusting Saw Guide Inserts. Saw guide inserts are provided so that
the guides can be adjusted for the size of saw blade to be used. The set of
inserts marked for the width of saw band being used should be selected. The
right hand insert (figure 9 on the following page) is placed in the milled
slot of the guide, and its adjusting screw is tightened lightly so that the
insert is able to slide in the slot but will still hold its