BANDSAW OPERATIONS

BANDSAW OPERATIONS - OD1646 - LESSON 1/TASK 1(c) Blade Wear. Bandsaw blades become dull from prolonged use, but someconditions promote greater than normal wear on the blades. Blades dullquickly if used at too high a speed for the material being cut. Also, ifthe material to be cut is too hard for the pitch of the blade, abnormal wearwill 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 dullsaw blades regardless of the sawing speed and feed. Premature blade dullingoften occurs from using too fine a pitch blade and from feeding too quickly.(d) Symptoms of Worn Blades. Several symptoms appear when a bandsawblade is dull. If the bandsaw blade cuts slowly or not at all when theworkpiece is fed by hand, the blade is probably dull. Blade teeth which arebright on the cutting edge also indicate a dull blade. Another sign of adull blade is when it becomes difficult to follow a line or when the bladeforces to one side or the other. A dull blade is also indicated when thechips from cutting metals are granular (except for cast iron which producesgranular chips with both sharp and dull blades). With the machine stopped,or with the bandsaw blade removed from the machine, run a finger slowly overthe teeth in the cutting direction. If sharp edges cannot be felt, theblade is dull and should be replaced.(2) Guide Selection. Standard saw guides are furnished with the bandsawmachines 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 ofthe saw blade to be used. Two special attachments, the angular blade guideand the miter guide, provide added capabilities to the bandsaw machine.(a) Adjusting Saw Guide Inserts. Saw guide inserts are provided so thatthe guides can be adjusted for the size of saw blade to be used. The set ofinserts marked for the width of saw band being used should be selected. Theright hand insert (figure 9 on the following page) is placed in the milledslot of the guide, and its adjusting screw is tightened lightly so that theinsert is able to slide in the slot but will still hold its13