How to Choose, Use, and Maintain Them to Get the Lowest Cost per Cut and Highest Quality Finish
Fabrication shops use band saws to cut all types of metals. To optimize productivity and achieve the best results, you need to choose a blade suited for the job at hand and make sure you use and maintain it so it lasts for as long as possible.
In this guide, we go through the complete process—selecting the right blade, breaking it in and using it, and looking after both the blade and band saw itself—to help you get the most out of your band saw and blades.
Choosing the Blade
Breaking It In
Using the Blade
Beyond the Blade
1. Choosing the Blade
To select the right blade for the job at hand, there are three main factors you need to take into account—the type of blade you need for the material being cut, blade thickness and width, and the characteristics of the teeth.
Type of Blade
The most common kind of blade used in metal fabrication today is bi-metal. For many shops, what makes bi-metal band saw blades the preferred choice is quite simply their versatility. Not only are they able to withstand impacts going through bundles and shapes, but they are also hard enough to be used with solid materials and even high-alloy steels.
Looking for Lenox bi-metal band saw blades? Shop online now!
Depending on your needs and the types of metal you need to cut, however, there are other types of band saw blades that might be suitable:
- Carbide (or carbide-tipped) band saw blades are ideal for cutting materials such as high-nickel alloy steel , HASTELLOY, titanium, MONEL, and INCONEL since they are able to withstand greater amounts of heat and maintain their edges for longer when used to routinely and continually cut especially hard metals.
- Carbon band saw blades are often seen as the economical choice for general-purpose cutting. They can be used to cut a variety of non-ferrous metals (mild steel, copper, bronze, brass, aluminum, and others), though they do tend to wear faster, which is why bi-metal band saw blades are usually recommended for industrial use.
Blade Thickness and Width
- Thickness: Thicker blades are generally stronger with straight cuts, though bending and twisting can put a strain on them.
- Width: The general rule of thumb is you should use the widest blade your machine will allow except when you’re cutting contours.
Not sure what blade you need? Use our blade selector tool to find the Lenox bi-metal band saw blade suited to your application.
Characteristics of the Teeth
There are a few elements you need to take into account here:
- Size: Tooth size probably plays the largest role in optimizing cutting efficiency. Keep in mind that although a large tooth will be able to work in small cross sections, a small tooth simply won’t be able to cut through large areas. If teeth are too small, the gullets will become clogged before the teeth actually exit the cut, causing teeth to simply rub across the surface of the material (instead of actually cutting) and creating excess heat that leads to the premature wear-and-tear.
- Pitch: This is defined as the number of teeth within a given distance. Cutting thin sections often requires a fine pitch (more teeth), while thicker sections will call for coarser pitches (fewer teeth). In general, you should always aim to have at least three teeth in the cut, though having between six and twelve teeth in the cut at all times is optimal.
In general, you should always aim to have at least three teeth in the cut, though having between six and twelve teeth in the cut at all times is optimal.
The other thing you need to keep in mind when it comes to pitch is whether it’s constant or variable. Blades with a constant pitch have teeth with uniform spacing, rake, and gullet depth and are the preferred choice for general-purpose applications. Variable pitch blades have a range of tooth sizes and gullet depths, which reduces noise and vibration and makes it easier to cut materials like structurals and tubing.
- Rake: Otherwise known as tooth angle, positive rakes are preferred when cutting thick solids or heavy-wall tubing while straight, or less positive, rakes are best when you’re working with structural or bundle cuts.
- Shape: There are a variety of tooth shapes available, but three of the most common are regular (has a straight (zero) rake and is used primarily for general-purpose jobs), hook (has a 10-degree positive rake and is used to quickly cut a range of non-ferrous metals), and skip (has a straight rake as well as shallow gullets that make it ideal for handling large sections of non-ferrous metals).
2. Breaking It In
Before you really start using your new band saw blade, you should always take the time to break it in. Teeth that aren’t broken in properly will wear more quickly, perform less consistently, and produce lower quality cuts.
The approach you should take when breaking in your blade will depend largely on the hardness or softness of the material you’re cutting:
- Hard-to-cut materials should be run at the normal surface feet per minute (SFM) with the feed rate or pressure adjusted to approximately three-quarters of the normal rate for the first few cuts or the first 25-75 square inches.
- Softer-to-cut materials should be run at the normal SFM with the feed rate adjusted to roughly half of the normal rate for the first few cuts or 50-100 square inches.
After those initial runs or square inches, increase the feed pressure gradually until you reach the normal rate, being careful to avoid or minimize vibration.
3. Using the Blade
Take Machinability into Account
Machinability means, in essence, the ease with which metal can be cut. Materials like carbon steel that have good machinability can be cut at higher speeds without putting too much strain on the blade. Other materials like stainless steel, which has significant quantities of nickel and chrome, need to be cut at slower speeds.
Never guess a material’s machinability, as the wrong speed can wear blades out very quickly. When in doubt, consult either the manufacturer’s guidelines or the blade catalogue.
Determine the Feed Rate
With band saws, the feed rate—the rate at which the blade cuts through the material—is measured in inches per minute (IPM). To determine the optimal feed rate, think about:
- Teeth per inch (TPI), otherwise known as pitch.
- Band speed, which is measured in surface feet per minute (SFM) and will vary depending on the machinability of the material being worked. Materials like aluminum that have good machinability can be run at speeds in excess of 150 SFM, while materials that have poorer machinability like tool steels may need to be run at speeds closer to 50 SFM.
- Chip load or the average quantity of material that each tooth will remove.
Remember, although higher feed rates can increase productivity, they also tend to reduce the life expectancy of the blade. Achieving the lowest cost per cut often means using techniques that allow operators to balance productivity and blade life.
Watch the Chips
Like a canary in a coal mine, chips can quickly confirm that everything is working as it should or warn you that something might not be right.
Assess your chips, keeping in mind that they should be:
- Warm (not hot) to the touch.
- The same colour as whatever material you’re working with.
- Shaped roughly of like a six (6) or a nine (9).
Pay Attention to Downfeed
Newer band saws often come equipped with automatic power downfeeds. Even these, though, need to be re-set occasionally to account for the gradual dulling of the blade. If the downfeed is manual, the operator needs to keep a constant watch on the rate and pressure, adjusting as needed to maintain a high quality of cut.
4. Ongoing Maintenance
Following a routine maintenance schedule is one of the best and easiest ways to ensure your machines and their components continue to perform their best.
When it comes to looking after your band saw and its blades, pay particular attention to:
- Band Wheels: Make sure you regularly inspect for chips and remove any you find so that the wheels will be able to turn without interference.
- Blade Tension: Improve accuracy by using a tension meter. Always de-tension the blade when you’re done using it and if it will be idle for an extended amount of time.
- Blade Cleaning Brush: Check to ensure the brush is making proper contact with the blade and that the bristles haven’t worn down. If your band saw currently has a metal-bristled brush, think about replacing it with a nylon brush. Nylon bristles won’t be as rough on your blade, and they don’t wear as quickly either.
Handle your blades carefully and look after them when they’re not in use. Take every precaution you don’t drop your blades while transporting them, and consider spraying older blades with a rust prevention product if they’re going to be stored for long stretches.
5. Beyond the Blade
Coolant plays a critical role in flushing chips out and, in tandem with the cleaning brush, ensuring they don’t make it back in. It also functions as a heat transfer agent, cooling the workpiece and lubricating the blade. Like with cars, coolant eventually degrades.
The ratio of water to coolant should be 10-1 or 12-1 for mild steel. For tougher materials, it will need to be richer—as much as 8-1.
One common mistake is assuming that coolant doesn’t evaporate and all you need to do is add water. Unfortunately coolant will evaporate, and if you only add water the ratio can climb as high as 30-1. This can lead to reduced lubricity, compromised heat transfer abilities, the formation of burrs, and premature wear.
Guides should always be positioned as close to a workpiece as possible, supporting them firmly on both sides and preventing them from moving while being cut. You should apply the maximum possible pressure when working with solid stock. With structural materials like tubes and pipes, use the greatest amount of pressure possible without deforming the piece.
If your workpiece isn’t adequately supported, you may notice the formation of “drop off” burrs. These will appear on the bottom edge of the workpiece and are created when the weight of the material causes it (the material) to simply drop off at the end rather than being cut off.
A few additional tips to keep in mind include:
- Lubricate all moving parts including fittings and machined surfaces.
- Inspect the idler wheel bearing to be sure it isn’t worn. As it wears it can cause your blade to become lightly angled, resulting I bevelled cuts. Whether you need to replace the whole idler wheel assembly or can replace the idler wheel bearing alone depends on the machine you have. When in doubt, always consult and follow the guidelines supplied by your manufacturer.
- If your band saw is older, check for pivot bar wear. In the majority of cases, the bar alone cannot be replaced and, if it can, the cost makes it prohibitive (it would cost nearly as much as a new machine).
- Listen to your band saw. If you hear your band saw making unhealthy sounds like squealing or grinding-type noises, that could be its way of telling you that you are overfeeding it or putting too much strain on the blade.
Get Expert Advice to Choose the Right Band Saw and Blade
If you’re unsure which band saw or blade will be best suited to the needs of your shop, contact a metal fabrication expert to discuss your options.
When choosing a distributor, make sure you consider:
- How long the company has been in business and the kinds and brands of machines they provide. What they offer needs to align with what your shop is looking for.
- Take into account the variety of machine types the supplier offers and the strength of their individual partners, keeping an eye out for industry leaders like HYD-MECH and Lenox.
- Ask the distributor you’re considering for information about some of their customers (both past and present).
- When you buy a band saw or band saw blade, it helps to know you can count on hassle-free maintenance throughout its lifecycle.
Taking the time to think about questions like these will enable you to make an informed decision and choose the band saw or blade that will give you the lowest cost per cut and highest quality finish.
Westway is the Canadian leader in metal forming and fabrication machinery. We supply band saws from leading manufacturers like HYD-MECH and are a Certified Master Distributor for original Lenox saw blades in both Canada and the US. Contact us today to discuss your needs, or shop for Lenox bi-metal band saw blades online!
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