Recommended Tool Speed Chart

These numbers are all conservative and based on what you can typically get away with on a manual or self-feed drill press or machine using High Speed Steel (HSS) tooling. The numbers for some materials presume the use of appropriate coolant. Higher quality tooling can often allow you to run faster RPM rates and/or more aggressive feed and thrust rates but typically require higher HP for the process as well.

Note that if you are using this chart to estimate the machine requirements for a multiple spindle drilling project, you will need to multiply some of the numbers by the number of holes you will be processing plus add a bit for internal gearing resistance, etc.

Aluminum

Recommended tool speed for aluminum
Measurements
Diameter 1/16 1/8 3/16 1/4 5/16 3/8 1/2 5/8 3/4 7/8 1
Inches 0.063 0.125 0.188 0.250 0.313 0.375 0.500 0.625 0.750 0.875 1.000
Millimeters 1.58mm 3.17mm 4.76mm 6.35mm 7.95mm 9.52mm 12.7mm 15.8mm 19.05mm 22.22mm 25.4mm
Specifications
RPM 10,000 6,000 4,000 3,000 2,400 2,000 1,500 1,200 1,000 875 750
Horsepower (HP) 0.01 0.07 0.10 0.20 0.28 0.38 0.67 1.00 1.37 1.84 2.30
Feed 0.001 0.003 0.005 0.007 0.008 0.009 0.012 0.014 0.016 0.017 0.018
Thrust 6 25 50 80 100 125 200 260 335 389 450

Brass

Recommended tool speed for brass
Measurements
Diameter 1/16 1/8 3/16 1/4 5/16 3/8 1/2 5/8 3/4 7/8 1
Inches 0.063 0.125 0.188 0.250 0.313 0.375 0.500 0.625 0.750 0.875 1.000
Millimeters 1.58mm 3.17mm 4.76mm 6.35mm 7.95mm 9.52mm 12.7mm 15.8mm 19.05mm 22.22mm 25.4mm
Specifications
RPM 10,000 6,000 4,000 2,400 1,800 1,500 1,200 900 750 675 600
Horsepower (HP) 0.01 0.05 0.10 0.18 0.28 0.35 0.55 0.80 1.18 1.50 1.80
Feed 0.001 0.002 0.003 0.004 0.005 0.006 0.008 0.010 0.012 0.013 0.014
Thrust 10 25 45 70 100 135 215 295 395 460 525

Cast Iron

Recommended tool speed for cast iron
Measurements
Diameter 1/16 1/8 3/16 1/4 5/16 3/8 1/2 5/8 3/4 7/8 1
Inches 0.063 0.125 0.188 0.250 0.313 0.375 0.500 0.625 0.750 0.875 1.000
Millimeters 1.58mm 3.17mm 4.76mm 6.35mm 7.95mm 9.52mm 12.7mm 15.8mm 19.05mm 22.22mm 25.4mm
Specifications
RPM 6,000 3,000 2,000 1,450 1,150 975 725 600 500 438 375
Horsepower (HP) 0.01 0.04 0.11 0.18 0.28 0.38 0.57 0.80 1.10 1.43 1.75
Feed 0.001 0.002 0.004 0.005 0.006 0.007 0.008 0.009 0.010 0.011 0.012
Thrust 15 40 100 150 200 260 350 480 550 675 800

Low Carbon Steel

Recommended tool speed for low carbon steel
Measurements
Diameter 1/16 1/8 3/16 1/4 5/16 3/8 1/2 5/8 3/4 7/8 1
Inches 0.063 0.125 0.188 0.250 0.313 0.375 0.500 0.625 0.750 0.875 1.000
Millimeters 1.58mm 3.17mm 4.76mm 6.35mm 7.95mm 9.52mm 12.7mm 15.8mm 19.05mm 22.22mm 25.4mm
Specifications
RPM 4,300 2,150 1,450 1,100 900 750 550 450 360 318 275
Horsepower (HP) 0.01 0.05 0.12 0.20 0.30 0.35 0.68 1.05 1.50 1.80 2.10
Feed 0.001 0.003 0.005 0.007 0.008 0.009 0.012 0.014 0.016 0.017 0.018
Thrust 30 80 145 230 340 440 700 1,050 1,300 1,650 2,000

Stainless Steel

Recommended tool speed for stainless steel
Measurements
Diameter 1/16 1/8 3/16 1/4 5/16 3/8 1/2 5/8 3/4 7/8 1
Inches 0.063 0.125 0.188 0.250 0.313 0.375 0.500 0.625 0.750 0.875 1.000
Millimeters 1.58mm 3.17mm 4.76mm 6.35mm 7.95mm 9.52mm 12.7mm 15.8mm 19.05mm 22.22mm 25.4mm
Specifications
RPM 3,200 1,550 1,025 775 620 510 400 310 260 215 170
Horsepower (HP) 0.01 0.05 0.12 0.21 0.40 0.48 0.85 1.45 2.05 2.58 3.10
Feed 0.001 0.002 0.003 0.004 0.005 0.005 0.007 0.009 0.010 0.0105 0.011
Thrust 40 100 180 290 425 465 780 1,100 1,500 1,700 1,900

Plastic / Wood

Recommended tool speed chart for plastic and wood
Measurements
Diameter 1/16 1/8 3/16 1/4 5/16 3/8 1/2 5/8 3/4 7/8 1
Inches 0.063 0.125 0.188 0.250 0.313 0.375 0.500 0.625 0.750 0.875 1.000
Millimeters 1.58mm 3.17mm 4.76mm 6.35mm 7.95mm 9.52mm 12.7mm 15.8mm 19.05mm 22.22mm 25.4mm
Specifications
RPM 7,000 4,000 2,700 2,000 1,600 1,400 1,000 800 700 625 550
Horsepower (HP) 0.01 0.07 0.10 0.12 0.14 0.16 0.20 0.30 0.45 0.58 0.70
Feed 0.00 0.00 0.00 0.00 0.00 0.01 0.01 0.01 0.01 0.02 0.02
Thrust 10 20 40 60 70 90 145 175 200 265 330

Fiberglass

Recommended tool speed for fiberglass
Measurements
Diameter 1/16 1/8 3/16 1/4 5/16 3/8 1/2 5/8 3/4 7/8 1
Inches 0.063 0.125 0.188 0.250 0.313 0.375 0.500 0.625 0.750 0.875 1.000
Millimeters 1.58mm 3.17mm 4.76mm 6.35mm 7.95mm 9.52mm 12.7mm 15.8mm 19.05mm 22.22mm 25.4mm
Specifications
RPM 18,000 9,000 6,095 4,584 3,661 3,056 2,292 1,833 1,528 1,309 1,146
Horsepower (HP)
Feed
Thrust

A typical drill press often has an RPM limitation of between 2000-3600 RPM. If the chart above specifies a higher RPM than your machine is capable of, it should not cause a problem to run at a lower RPM. For instance, many people drill 1/16″ holes at less than 10,000 RPM with no problems.

The process of drilling holes in metal or similar materials without coolant is possible but not suggested. In most metals, the RPM rate can be decreased to 25% of what is shown above to drill without coolant. However, in stainless, the RPM rate must be decreased significantly more. Stainless steel does not dissipate heat easily. It will almost immediately ruin the cutting edge of your tool. It is often helpful to take a heavier cut in stainless than a lighter one to keep the tip of the tool in “cool” material rather than near the surface that was recently heated up by the last pass of the tool tip. Check with your drill tooling manufacturer for specific requirements and limits.

Reaming generally runs at 2/3 or less the RPM of drilling. AutoDrill suggests the same horsepower rating in case the hole is undersized, etc. The last thing you want is to stall your machine or motor. Check with your reamer tool manufacturer for specific requirements and limits.

Tapping generally runs at around 1/3 to 1/4 the RPM of drilling. We suggests a minimum of 2-3 times the horsepower of drilling for standard tapping processes and higher numbers for flow or roll form tapping. Check with tap your tooling manufacturer for specific requirements and limits.

Why do my tools wear quickly or break?

Note that excessive tool wear or breakage is often caused by:

  • Improper surface speeds
  • Improper feed rates
  • Improper cutting tool type or material (HSS vs TiN vs Carbide, etc.)
  • Dull tooling
  • Hard spots in the material such as scale, silica, imperfections, etc.
  • Improper coolant or lubricant type
  • Inadequate coolant or lubricant (overall for chip removal, rubbing, etc.)
  • Inadequate coolant or lubricant (at the tip of the tooling)
  • The tool is not rigid enough (try drill bushings or guides, guide rods on the drilling machine, etc.)
  • Too deep of a cut without proper chip removal – Chip packing (try peck drilling, air blast or coolant through the tool options, etc.)
  • Tools that were manufactured or sharpened incorrectly. (watch those clearance, rake and lip angles as well as rough surfaces, etc.)

Calculating cycle time when drilling:

We can help you lower your cycle time when drilling holes in a part or multiple parts. Generally, this is the calculation we use to figure out the time it will take to perform a process:

Depth divided by feed = rotations
Rotations divided by RPM = minutes
Minutes multiplied by 60 = the seconds the process takes.

(Depth = 30% of the diameter of the tool plus the thickness of the material)
Add in stroke up to product time
Add in stroke back to home time
Add in clamp and unclamp time
Add in any human factors, etc.
Add in time for potentially dull tooling, etc.
Add in time for less than adequate machine thrust, etc.

We use the charts above to estimate these numbers.

Files

Chart (PDF)

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Chart (Excel)

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