Rigging a measuring gauge to check tire “round” (you can use a business card set 1/8” from tire and observe the distance between card and wheel as it spins)
Checking Vertical Plane
Making sure each wheel is plumb using a bubble level.
Calibrating Horizontal Plane
Wheel alignment: the string should touch both wheels at 3 and 9 o’clock (or 6 and 12, as the case may be).
Measuring Blade Tension
Measuring blade tension with a surface tension gauge.
Adjusting Blade Guide Assembly
Loosening the blade guide assembly adjusting hardware.
In keeping with our goal of getting the lowest cost per cut for our bandsaw customers, we are declaring the month of August to be National Tune Your Saw Month.
Over-tensioning, poor wheel alignment and a host of other maintenance issues will adversely affect the life of both blade and machine. Keeping your saw in tune is a must in order to avoid losing money in the form of frequent blade changes, poor performance and premature equipment failure.
We turned to “Bandsaw Brad” Kirkaldy, a 30-year veteran of the saw business, for practical tips on the occasion. He is currently a partner at Noble Machinery Co., Inc., a company that distributes the Pallet Hawg band saw as well as refurbishing many brands for resale.
Mr. Kirkaldy outlined a seven-step process to bring a saw into fighting trim. While some of his methods may exceed the capacities of your in-house maintenance go-to guy, most of his suggestions are things that any of us could and should attempt for the sake of smoother operations. He actually recommends repeating this tuneup on a monthly basis:
Step 1: With the saw blade removed, spin the wheels or pulleys by hand, checking for signs of bearing wear. Wheels should spin smoothly and without a trace of wobble or play.
Step 2: Check wheels for “round.” Rig a business card or similar reference object parallel with the tread within 1/4” from the edge of the wheel and spin the wheel, observing if the distance between the wheel and the card varies appreciably.
Step 3: Check wheels for proper balance. This is a little tricky to determine in the field, but a vertically-mounted wheel should not be coming to rest at the same spot when spun. If balance is in question, wheels with tires can be balanced at a tire store. They typically do not go out of balance during normal wear.
Step 4: If your wheels have tires, check air pressure. Refer to product documentation or labeling for recommended pressure for your machine. Kirkaldy said that a typical pressure is 50psi, and that underinflation is far more problematic than overinflation. Your tires should be solidly firm with a crown along the center of the tread.
Step 5: Stretching a string or straightedge across two wheels, check for alignment. The wheels must be oriented on the same plane for the blade to track properly.
Step 6: Install the blade and check blade tension. Refer to product docs or labels to determine recommended tension for your blade. Some machines are equipped with a tension meter; otherwise a tool that measures surface tension (available from Hub if you don’t have one) is a necessity. Kirkaldy has found that many operators will increase tension on the saw blade to correct a tracking problem instead of addressing the underlying source of the problem. Increasing the tension often will resolve the symptom, but the over-tensioning introduces new, more sinister problems such as premature blade and bearing wear. Restoring the tension to the prescribed lbs. surface tension value (typically 12,000 lbs.) improves performance. A properly tensioned saw will deflect no more than ¼” when pushed with the palm of your hand. Tracking problems, if they still exist after this tune-up, should be repaired by a technician.
Step 7: With guide bearings removed, it is time to make the final tweaks to the blade tracking using the adjusting set screws or similar hardware employed by your brand of saw. Sawblade should track on the crown of the wheels as they spin. When satisfied, replace the guide bearings 1/16” away from blade. These bearings are meant to be guardrails and only contact the blade infrequently.
If any of the tests you perform reveal anomalies like bearing wear, you should have your machine serviced by a competent repairman. Increasing surface tension may mask the problem for a little while, but your saw will never work as it was designed until all these factors are working properly.
Brad Kirkaldy can be reached at firstname.lastname@example.org