Cutting Metal With a Band Saw: Capacity, Speed, and Material-Specific Technique
You have a band saw and you want to cut metal. You have been using it for wood and you are not sure if it can handle metal, what blade to use, or what speed to run it at. You know that cutting metal is different from cutting wood, but you are not sure where to start. You need a guide that covers the basics of metal cutting on a band saw.
Cutting metal on a band saw is possible with the right setup. The key factors are blade type, blade speed, lubrication, and feed technique. Getting any of these wrong will result in poor cuts, short blade life, and potential damage to the saw.
Saw Types for Metal Cutting
Portable Band Saws
Portable band saws (Milwaukee M18, DEWALT 20V) are designed for metal cutting. They run at 200 to 550 SFPM, which is the right speed range for most metals. They use bi-metal blades and can cut pipe, unistrut, angle iron, and bar stock.
Best for: Field cutting of pipe, conduit, unistrut, and bar stock.
Horizontal Metal Cutting Saws
Horizontal saws are designed specifically for metal cutting. They run at 60 to 300 SFPM with variable speed. They have a vise to hold the material, hydraulic downfeed, and coolant systems. They cut material up to 7 to 14 inches depending on the saw.
Best for: Shop cutting of bar stock, pipe, and structural steel to length.
Vertical Metal Cutting Saws
Vertical saws with speed reduction can cut metal. The speed must be reduced to 100 to 300 SFPM for metal cutting. Some vertical saws have a gearbox for speed reduction. Others use a VFD (variable frequency drive) to control motor speed.
Best for: Contour cutting of flat stock and sheet metal.
Woodworking Band Saws
Standard woodworking band saws run at 2500 to 3000 SFPM. This is too fast for metal cutting. The high speed will destroy the blade in seconds and can be dangerous. You cannot cut metal on a woodworking band saw without speed reduction.
Exceptions: Some 14-inch saws (Delta 28-207, Jet JWBS-14OS) have a two-speed gearbox that reduces speed to about 300 SFPM for metal cutting. If your saw has this feature, you can cut metal with the right blade.
Blade Selection for Metal
Blade Material
Bi-metal M42: The standard for metal cutting. The M42 edge (67 to 69 HRC) can cut mild steel, stainless steel, aluminum, and cast iron. Lasts 3 to 5 times longer than carbon steel.
Bi-metal M51: A harder edge (69 to 70 HRC) for tougher materials. Better for stainless steel and harder alloys.
Carbide-tipped: The best for production cutting. Carbide teeth (90+ HRC) cut metal efficiently and last 5 to 10 times longer than bi-metal. Expensive but worth it for production.
Carbon steel: Not recommended for metal cutting. Dulls quickly and cannot handle the heat generated.
TPI Selection
| Material Thickness | Recommended TPI |
|---|---|
| Under 1/4 inch | 18 to 24 TPI |
| 1/4 to 1 inch | 10 to 14 TPI |
| 1 to 2 inches | 8 to 10 TPI |
| Over 2 inches | 6 to 8 TPI |
Rule of thumb: At least 3 teeth should be in the material at all times. For 1/4 inch material, you need at least 12 TPI (3 teeth in 1/4 inch). For 1 inch material, you need at least 3 TPI.
Variable pitch: Recommended for mixed work. Alternating tooth spacing (like 10/14) breaks up vibration and handles a range of thicknesses.
Tooth Profile
Hook tooth (positive rake): The aggressive bite shears metal chips. Best for thick stock and production cutting.
Skip tooth (0 degree rake): Large gullet for chip clearance. Good for general metal cutting.
Regular tooth (negative rake): Too conservative for most metal cutting. Avoid unless cutting very thin material.
Speed Requirements
| Metal | Speed (SFPM) |
|---|---|
| Mild steel | 200 to 350 |
| Stainless steel | 60 to 150 |
| Aluminum | 200 to 400 |
| Cast iron | 150 to 250 |
| Brass | 200 to 350 |
| Copper | 200 to 350 |
Start at the low end of the speed range and increase if the cut is clean and the blade is holding up. If the blade dulls quickly or the cut is rough, reduce speed.
Portable saws: Most run at a fixed speed (200 to 550 SFPM). If your saw has a variable speed dial, set it to the lowest speed for metal cutting.
Horizontal saws: Use the variable speed control to match the speed to the material. Start at the lowest speed and increase as needed.
Lubrication
Lubrication is critical for metal cutting. It reduces heat, prevents chip welding, and extends blade life.
Cutting fluid (water-soluble): The best choice for production cutting. Flood the cut zone with cutting fluid using the saw’s coolant system.
Cutting oil (sulfurized): Good for steel and stainless. The sulfur additive provides extreme-pressure lubrication.
WD-40: Marginal but better than nothing for occasional cutting. Good for aluminum.
Wax sticks: Good for portable saws. Apply continuously during the cut.
Never cut metal dry if you can avoid it. Dry cutting generates excessive heat, shortens blade life by 50 to 80 percent, and produces poor cut quality.
Cutting Technique by Metal
Mild Steel
Speed: 200 to 350 SFPM. TPI: 10 to 14 TPI for general work. 6 to 8 TPI for thick bar. Lubrication: Cutting fluid or cutting oil. Feed: Steady, moderate pressure. Let the blade cut, do not force it. Notes: Mild steel is the easiest metal to cut. Most bi-metal blades handle it well.
Stainless Steel
Speed: 60 to 150 SFPM. Start at the low end. TPI: 10/14 variable pitch bi-metal. Carbide-tipped for production. Lubrication: Cutting fluid or sulfurized cutting oil. Essential. Feed: Steady, firm pressure. Do not let the blade rub. Stainless work-hardens if the blade rubs. Notes: Stainless is tough and work-hardens. Keep the blade cutting, not rubbing. If the cut slows, increase feed pressure slightly.
Aluminum
Speed: 200 to 400 SFPM. TPI: 10/14 or 14 TPI. Coarser than for steel because aluminum chips are soft and need large gullets. Lubrication: WD-40 or cutting fluid. Prevents chip welding. Feed: Steady, moderate pressure. Do not force. Notes: Aluminum is soft but gummy. Chips tend to weld to the blade. Use lubrication and a coarser TPI than you would for steel.
Cast Iron
Speed: 150 to 250 SFPM. TPI: 10 to 14 TPI bi-metal. Lubrication: Dry cutting is acceptable for cast iron. The graphite in cast iron provides natural lubrication. Feed: Moderate pressure. Cast iron is brittle and chips easily. Notes: Cast iron is abrasive and dulls blades faster than mild steel. Expect shorter blade life.
Brass and Copper
Speed: 200 to 350 SFPM. TPI: 14 to 18 TPI. Lubrication: Cutting fluid or WD-40. Feed: Light to moderate pressure. These metals are soft and can grab the blade if feed is too aggressive. Notes: Brass and copper are soft and gummy. Use a finer TPI than for steel and keep the feed light to prevent grabbing.
Blade Break-In
New bi-metal blades need a break-in period for maximum blade life. Run the first 10 to 20 cuts at half feed pressure. This lets the tooth tips wear evenly and prevents chipping. Skipping break-in can reduce blade life by 30 to 50 percent.
FAQ
Can I cut metal on a woodworking band saw?
Only if the saw has speed reduction that drops the speed to 100 to 300 SFPM. Standard woodworking speed (3000 SFPM) is too fast and will destroy the blade.
What blade do I need for cutting metal?
A bi-metal blade with the correct TPI for the material thickness. Carbon steel blades are not suitable for metal cutting.
What speed should I cut metal at?
60 to 350 SFPM depending on the metal. Mild steel: 200 to 350. Stainless: 60 to 150. Aluminum: 200 to 400. Start at the low end and increase if the cut is clean.
Do I need cutting fluid for metal cutting?
Yes, for most metals. Cutting fluid reduces heat, prevents chip welding, and extends blade life by 50 to 80 percent. Cast iron can be cut dry.
Why does my blade dull so fast in stainless steel?
Stainless work-hardens when the blade rubs. If the feed is too light, the blade rubs, the surface hardens, and the blade dulls. Use steady, firm feed pressure and keep the blade cutting.
What TPI should I use for cutting metal?
Match the TPI to the material thickness. At least 3 teeth should be in the material. Under 1/4 inch: 18 to 24 TPI. 1/4 to 1 inch: 10 to 14 TPI. Over 1 inch: 6 to 10 TPI.
References
- LENOX Tools. “Metal Cutting Blade Selection Guide.” LENOX Industrial Division.
- MK Morse. “Master Cobalt Blade Performance Data.” MK Morse Company.
- Starrett. “Bi-Metal Blade Specifications for Metal Cutting.” L.S. Starrett Company.
- Milwaukee Tool. “Portable Band Saw Cutting Guide.” Milwaukee Tool.
- Practical Machinist. “Band Saw Metal Cutting Tips and Techniques.” practicalmachinist.com.
