Bandsaws are among the most vital tools used in the metals industry. Industrial cutting operations rely on efficiency and precision from these saws, which includes using the right saw blade for the machine and the job overall.
That is why The L.S. Starrett Co. specialists inspect several aspects of the sawing operation before they make a recommendation for one of their blades. But there is much more to productivity than just blades. Their inspections touch on numerous components of the saw, leading to a healthy sawing operation. With access to Starrett professionals, Sawing Productivity learned about their recommended best sawing practices to share them with our readers.
Guiding the blade
First up are guide arms, also referred to as band arms, which extend from the saw’s frame and hold the blade guides in place. They are positioned directly behind the blade and control deflection under cutting pressure while keeping the blade tracking straight. When the arms are poorly adjusted, the blade guides will not function properly.
When a blade guide is broken or worn, the blade will ride improperly, which leads to grooves along the side of the blade. This shortens the life of the blade and causes crooked cuts that add more material to the costly scrap pile.
But it is also up to the saw operator to ensure the guide arms are properly positioned. Arms can be adjusted closer to or farther from the workpiece depending on the size of material being cut. If the arms are too far apart, the blade tends to bow, which leads to premature cracking.
Patrick O’Brien, regional sales manager at Starrett, says the guide arms need to be as close to the maximum diameter of the material as possible because it influences the beam strength of the blade, which is its ability to resist bending or deflecting under cutting pressure.
“Say you’re cutting an 8-in. round piece of titanium,” he says, “and you have a guide arm on one side very close to the maximum diameter and you have the other guide arm 2 ft. away. The beam strength of the blade is going to give out because there is nothing to support the blade as it moves quickly through the material.”
Moving the guide arm in closer to the material provides more support, preventing the blade from becoming “flimsy,” O’Brien says. With the arms properly positioned, the blade benefits from the stiffness provided by the band wheels and the support of the carbide guides as it enters the material. This support becomes increasingly critical when cutting larger diameters or tougher alloys like titanium.
Using cutting fluids
Consumables like cutting fluids are sometimes underappreciated in the role they play on shop floors, but coolants and lubricants are critical as they cool blades, lubricate teeth and flush chips away from the cutting zone. If the amount of fluid used is inadequate, blades quickly overheat, teeth wear and chips begin to build up, compromising the quality of the cut. No saw blade is made to last forever, but failing to keep tabs on cutting fluids will ultimately shorten the life of the blade.
That is why Starrett places cutting fluids high on its healthy sawing operation checklist, emphasizing that a “rich” cutting fluid does a better job of coating and lubricating the blade throughout the entire cut. Starrett experts advise that coolant should wash over the blade as it enters and exits the cut, recirculating throughout the cutting process.
However, as the cutting fluid is used, water evaporates from the solution, which is why saw operators need to replace it before it breaks down and fails to perform. Another tip for operators is to stay on top of the rate of fluid flow and clear out the chips so they cannot fly into the machine and block the flow of coolant.
In some sawing operations, cutting fluid should not be used at all. In the case of vertical machines, for example, fluid will drip down onto the lower band wheel. In these situations, Starrett specialists recommend using a lubricant stick on the teeth of the blade, which reduces heat buildup and extends the life of the blade.
Tracking and alignment
Blade tracking is often confused with band wheel condition, but O’Brien says the two serve different purposes. Proper tracking ensures the blade rides correctly on the wheel without contacting the wheel’s back flange, also called a lip, which is designed to prevent the blade from sliding off the wheel.
“You don’t want that blade flush up against either of the wheels,” O’Brien says. “If the blade is constantly in that position, it’s going to wear out, but more importantly, it’s going to wear out your wheels, too.”
A simple best practice can avoid the situation altogether. Experienced saw operators simply place a sheet of paper between the blade and the wheel flange during installation.
“Make sure you can still remove the paper without it ripping,” O’Brien says. “That means there’s a little area in between the blade and the wheels.”
While some issues can be corrected during installation, alignment issues often show up once cutting begins. Sophisticated saws can detect when a cut begins to drift and stop automatically when tolerances are exceeded. In less automated environments, saw operators must recognize the signs. Common causes of tracking and alignment problems include loose or worn blade guides, incorrect blade selection, improper guide tension and uneven tooth wear.
“The rule of thumb when installing a guide is to tighten it to the max by hand and then back off a quarter turn,” O’Brien says. “The guides are being used as guides, not steering the blade.”
Overtightened blade guides leave telltale signs, including visible wear marks and indentations along the blade body. Uneven tooth wear can also cause the blade to walk in the cut.
“When you have a sharper tooth on one side of the blade than the other, it’s going to naturally deviate,” O’Brien says. “That’s evidence that it’s time to replace the blade.”
Improper blade break-in compounds these problems, often resulting in jagged teeth and sections of the blade that cut inconsistently until failure occurs.
Chip removal
Even though chips are technically small, they can cause huge headaches. Therefore, another helpful saw addition is the blade brush, a rotating wire brush designed to clear chips from the blade gullets during cutting. This prevents chips from sticking to the blade, which extends blade life. Clearing chips from the gullet reduces rough cuts and prevents damage to bearings, wheels and guides. O’Brien says a quarterly check will often catch a worn-out brush, which is one of the least expensive replacement parts to buy.
“A worn brush could be the reason why chips aren’t being removed from the cut,” he says, “especially if you’re working with hard material. It’s important to keep checking the brush because it could affect blade life, too.”
Felipe Arntsen, Starrett’s product manager for sawing and hand tools, says checking the brush is easy, requires no disassembly and should be part of any saw operator’s routine before cutting.
Maintenance matters
As for saw machine maintenance, O’Brien stresses that regular inspection is essential to protecting one of the most heavily used machines in the shop.
“The saw machine is the most abused machine in the factory,” he says. “Therefore, there isn’t any replacement for quarterly or biannual maintenance.”
Routine maintenance includes calibrating blade speed using a pocket laser tachometer, which is crucial for achieving optimal cutting performance and prolonging the life of the blade. Using a tachometer is especially helpful when switching between different types of material or breaking in a new blade as it allows the saw operator to quickly verify and adjust the speed. O’Brien recalls a recent customer visit where inaccurate speed readings led directly to blade failure.
“The customer’s DRO [digital readout] was reading 80 surface ft. off of my tachometer’s DRO,” he says. “And that was the absolute cause of failure of the blade.”
The financial implications add up quickly. Consistent maintenance reduces cutting fluid waste and extends the life of blades that can cost $200 to $300 each. Overall, however, proper maintenance protects the saw – an investment that cost up to $100,000 and beyond.
“If a saw goes down because you’ve broken three blades on it,” O’Brien says, “it’s a root cause analysis failure.”
It is also a major downtime issue that costs a fabricator in lost business or longer turnaround times. To keep a saw’s uptime high, Arntsen says a complete 20-point inspection can be a gamechanger. It might not be a part of every saw operator’s daily routine, but checking a few vital components only “takes a few minutes of your day and can save a lot of time and headache later.”
