Craftsman 351.21 4300 Tensioning Blade, Tracking Blade, Adjusting Blade Guides, Blade Pitch

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TENSIONING BLADE

Refer to Figure 15.

Tension blade by rotating handwheel (Key No. 38). Be sure blade guides do not interfere with blade path.

Tighten blade until it is properly tensioned.

A properly tensioned blade will ring slightly when back of blade is plucked (like a string on an instrument).

NOTE: Check tension of new blade. Additional tension may be required after a few minutes of operation.

TRACKING BLADE

Refer to Figure 15.

Track blade after it has been tensioned. A change in blade tension will affect wheel alignment. Proper tracking is achieved when upper and lower wheels are aligned.

Set screws (Key No. 23) are used to align the track- ing bracket to the saw frame.

Turn idler wheel (Key No. 5) by hand and observe how blade rides on the wheels.

If blade rides away from the cabinet, tilt wheel up by turning knob (Key No. 30) clockwise.

If blade rides into cabinet, tilt wheel down by turning knob counterclockwise.

ADJUSTING BLADE GUIDES

Refer to Figures 8 and 16.

NOTE: Adjust blade guides only after blade has been properly tensioned and tracked.

Blade guides support blade at sides and rear of blade, and prevent twisting or deflection.

Upper blade guides employ guide blocks for side support and a grooved bracket at rear.

Blade guide bracket (Key No. 20) should be posi- tioned so guide blocks (Key No. 21) on either side of blade will support as much of blade width as possible without interfering with the tooth set.

Adjust guide bracket depth by loosening set screw (Key No. 40) and sliding bracket into position. Secure position of bracket by tightening set screw.

Loosen bolts (Key No. 24) and adjust guide blocks (Key No. 21 ) to sides of blade. Use a feeler gauge to check that guide blocks are 0.002" away from blade.

Lock adjustment by tightening bolts.

Adjust the height of upper guide assembly to clear the workpiece by 1/4".Loosen locking knob (Key No. 30) and use handle (Key Nos. 37 and 38) to slide guide bar down until the upper guide assembly clears workpiece by 1/4".Tighten locking knob.

Lower blade guides employ two guide blocks for side support. Lower guide bracket is spaced close to table surface to minimize unsupported length of blade.

NOTE: Lower blade guard (Key No. 56) must be removed to adjust lower blade guides.

Loosen bolts (Key No. 26) to adjust lower guide bracket (Key No. 19) so guide blocks do not interfere with blade set. Loosen socket head bolts (Key No. 24) for guide blocks (Key No. 21) and adjust guide blocks to 0.002" from each side of blade.

0.002"

0.002"

Blade

Guide

Blade

Figure 8 - Blade Guide Adjustment

NOTE: 0.002" gap between blade and both blade guides.

BLADE SPEED AND TYPE SELECTION

Refer to Blade Speed Chart.

Consult Blade Speed Chart to determine blade speed and blade type for required cutting operation. Blades vary depending on type of material, size of workpiece and type of cut that is being performed. Characteristics which make blades different are width, thickness, type of tooth and blade pitch.

Width of blade describes distance from tip of a tooth to back of blade. Width of blade will affect rigidity of blade. A wider blade will wander less and produce a straighter cut.

Width of blade also limits the smallest radius which can be cut. A 1/Z'wide blade can cut about a 1/2" radius. Blade thickness describes the distance between sides of blade. A thicker blade has more rigidity and stronger teeth. A narrow thick blade would be used to cut curves in piece while a wide thin blade would be used to make long, straight cuts.

Blade manufacturers are prepared to supply information about blades for specific applications.

BLADE PITCH

Refer to Blade Speed Chart.

Pitch describes number of teeth per inch. A blade with more teeth per inch will produce a smoother cut.

Type of material being cut determines number of teeth in contact with work.

There should always be at least three teeth in con- tact with workpiece to avoid shocking blade. Blade shocking occurs when pitch is too large and blade

tooth encounters too much material. This can strip teeth from blade.

When pitch is too small the gullets of the teeth will fill up, leading to the creation of excess heat.

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Contents Sears, Roebuck and Co., Hoffman Estates, IL 60179 U.S.A Craftsman ++Prepare Work Area for JOB ONE-YEAR Full Warranty on Craftsman Professional ToolKnow HOW to USE Tool Be Prepared for JOBMotor Mount RIP FenceRPM Grounding Instructions Power SourceElectrical Connections Extension CordsOperating SAW Controls SpecificationsRemoving Blade Blade Speed and Type Selection Adjusting Blade GuidesTensioning Blade Tracking BladeChanging Blade Speed Thickness MaterialChip Blower Adjusting Table AngleUsing RIP Fence Contour CuttingBlade Welding Tooth SpacingAnneal Blade After Grinding Clean Welder JawsBlade Annealing Grinding BladePossible Causes SymptomCorrective Action Corrective Action Possible CausesModel 351.21 KEY NO. Part no KEY Description QTYReplacement Parts Illustration for Welder Description KEYReplacement Parts Illustration for Wheels and Speed Handle Description QTY KEY NO. Part noModel Replacement Parts Illustration for TableQTY Description Replacement Parts Illustration for Motor and Blade Drive Description QTY Parts Repair Matter Who Made It, no Sold