Getting the right speed on a drill press when working with metal is important. The ideal speed for a drill press depends on three main factors: the size of the drill bit, the type of drill bit, and the material being drilled. Matching these factors correctly ensures efficient drilling.
A typical drill press has a speed limit of between 2000, 3600 RPM. If a speed chart shows a higher RPM than the machine can handle, it should not cause problems if you use a lower RPM. But for metalwork, low speeds are critical.
Right Speed for Drilling Metal
The lowest speed on a normal five-speed or wood drill press is barely enough for many metal jobs and not at all for others.
Benchtop presses good for metal tend to have more speeds. Five speeds is common on wood-only models, while 12 to 15 speeds is typical on metal-capable ones. A drill press with a minimum speed of 460 RPM would work much better for metalwork than one with a 700 RPM minimum.
Some metalworkers like to go down to about 50 RPM for certain tasks. It really depends on how much material the cutting edge of the bit is removing.
For quick reference in 1018 steel, a quarter-inch bit should run about 1200. 1300 RPM 900 RPM for three-eighths inch, and 600 RPM for half inch. Harder or tougher steels should run slower. At 900 RPM, an eighth-inch bit’s cutting edge is going through something like 700 inches of material in a minute, while a two-inch bit’s edge is going through more like 11,000 inches of material.
That is a huge difference.
Metal drills are usually made of high speed steel, which for mild steel has a recomended cutting speed of 30 meters per minute. There is no other factor that dulls cutting tools quicker than excessive RPM. The general rule is that the larger the hole, the slower the speed should be.
Larger bits tend to grab, and the last thing anyone wants is a workpiece becoming a makeshift propeller.
Feed equals.001 inch per revolution for every 1/16 inch of drill diameter, plus or minus.001 inch on the total. Speed equals 80 surface feet per minute in 100 Brinell hardness material, and speed should be reduced 10 surface feet per minute for each additional 50 points of Brinell hardness. Using lube or cutting oil helps a lot.
Heavy feed works well. Speed charts for different materials and drill bit types are a great reference to keep nearby. Recommended speeds for various accessories range from 200 to 3000 RPM based on material and bit size.
Wood is not as picky, but metal demands attention to speed alwaysnow.
