Video Doctor's Web Site-Fettling a Bandsaw

WARNING!	ALL checks and alignments should be performed with the power cord disconnected!
The first step in tuning your bandsaw is checking that the wheels are round and running true. In this photo, a dial indicator is checking circumferential run-out. This should measure less than .005". If more than this, remove the tires and check the bare wheel at the crown. If it is OK the tires should be replaced, as they are the cause of the excessive run-out. This check should be performed on both the top and bottom wheels. These checks should be performed with a blade mounted and tensioned.
The next check is for lateral runout of the wheels. In this photo, a dial indicator is checking the lateral runout of the wheel. This should measure less than .003". If more than this, either replace the wheel, or have a machine shop attempt to true it. Minor adjustments can be made by carefully twisting the wheel by hand and rechecking repeatedly. The wheels are aluminum and will crack easily, so don't go overboard in your attempt to straighten them. As above, this check should be performed on both top and bottom wheels.
The next check is for co-planar alignment of the wheels, both horizontally and vertically. Place a known good straight-edge at the front of the bottom wheel, touching both edges, and extending to the top wheel. Turn the tracking adjustment until there is an equal clearance between the straight-edge and the top wheel at both the top and bottom edges. If there is no space, then your wheels are aligned in the vertical plane. Then check the rear of the wheels in the same manner. There should be an equal amount of clearance at the front and the rear of the wheels. If not, the frame or wheel mountings are twisted or misaligned horizontally.
To correct horizontal misalignment, you may try loosening the top frame to bottom frame fastening bolt as pictured here. Loosen the bolt and move the top portion of the frame in the desired direction and recheck the clearances as above. Since the two frame castings are doweled together, there is a limited amount of movement attainable by this procedure. If your are certain that the frame is not damaged, the bearings in the top wheel are good, and the mount is not damaged, you can attempt to enlarge the dowel holes until alignment is achieved.
To correct for a vertical misalignment of the wheels, remove the top wheel retaining nut and move the top wheel in or out by using shims, as pictured here. Generally, it is necessary to add shims, but if you need to reduce the thickness, grind the stock shim on the side until the desired clearance is reached.
This is a potential problem area for these bandsaws. The top wheel contains two bearings, separated by a spacer and compression (wave) washer. The outer bearing is supposed to be a tight friction fit in the wheel, but the clearances are usually excessive, leading to slippage of the bearing in the bore.
This is the side of the bearing, showing the circular wear marks indicative of the bearing spinning in the wheel's bore. This will eventually render the top wheel unusable. The bore contains similar wear marks.
If caught before permanent damage is done to the wheel, the use of thread locking compound in the bore and on the outer shell of the bearing is recommended when remounting the wheel and bearing assembly to help prevent further slippage. Torque the retaining nut sufficiently to prevent the wheel from working loose. The use of thread locking compound is probably advisable here as well, as this nut has a tendency to loosen itself in time.
After the wheels are aligned and reassembled, remount the blade, tension it, and set all guides and thrust bearing clear of the blade. Align one of the guides with the edge of the blade, but not touching it. This will be used as a visual indicator to check the alignment of the guide post as it moves through it's extremes.
First move the post all the way down and tighten, then move it all the way up and tighten. Check the alignment of the blade to the guide that you set in the above step in each position and note any changes. No differences means that your casting was properly milled and minimal guide adjustments should be needed when moving the post for varying stock heights. Little can be done to correct misalignments, although shimming one side of the top to bottom frame junction could be attempted.
Another problem on these saws is the poor quality of the mill work on portions of the castings. When mounting the riser kit, you must mount a bracket for the auxiliary guard at the circled location. The bracket usually doesn't fit very well, and some file work on the cast iron tab is called for in order to get a good, square fit.
Another problem with these saws is the table pivot brackets. Although the table tilt trunnions are cast iron, the brackets attached to the cast iron top are aluminum, and the mounting holes are oversized. The small bolts often loosen themselves and the table will not stay steady or secure.
Another problem is the aluminum rivets that hold the degree scale onto the brackets. These rivets are sometimes not fully seated, and should be tapped flush to fully secure the scale. As noted in the next photo, the rivets also often stick out into the path of the affixing gibs, interfering with smooth movement when tilting the table.
As you can see in this photo, the pins of the rivets extend into the path of the gib. Excess pin length can be trimmed with diagonal nippers, and the remainder peened down, thus securing the rivet from the back.
When reassembling the table, use thread locking compound to prevent loosening of the screws. Leave the screws slightly loose, so that the table can be aligned when reassembled.
The table trunnion/guide assembly and it's two affixing screws should also be checked for tightness, and thread locking compound should be used on these as well.
Reassemble the top to the frame with the table bracket screws still slightly loose, but the trunnion (table tilt) knobs snugged down. Align the top by scribing a line down a thin piece of stock and cutting along the line, carefully keeping the stock positioned as it was cut. This will be used to align the miter slot parallel with the blade cut. Move the table as needed to align the stock parallel with the miter slot and tighten the bracket screws.
Once the table is parallel to the blade, set the 90 degree table tilt stop with a known good square or angle protractor. Tighten the stop locking nut and recheck the angle after tilting the table and returning it to the 90 degree position.
Lastly, visually check the belt for wear or excessive runout. Also check the pulleys for loose setscrews and proper alignment. The belt should not run skewed to the pulley sheaves. Move one of the pulleys in or out as necessary to properly align. Warped or wobbling pulleys should be changed. Motor shaft pully is 5/8" bore, bandsaw wheel shaft pully is 3/4" bore.