304 stainless steel drilling RPM

Find starting drill RPM for 304 stainless steel using bit diameter, supplier cutting data, and your machine speed limit.

Starting estimates only. Use the cutter supplier’s data and your machine’s limits for the actual operation.

Supplier cutting data

Machine limit

Starting values are examples. Replace them with your measurements.

Result

Enter your values, then calculate.

Calculation method

RPM = 1000Vc/(πD). Feed = RPM × feed/rev; milling multiplies chip load by flute count.

LittleMachineShop cutting speed tablesMethod 2026-10-05.1. Independent review pending.

Choosing a starting RPM for 304 stainless

Reference preset: 304 stainless steel drilling RPM. These notes describe the original preset, not changes made in the calculator above.

The stainless selection starts with the supported general reference of 50 ft/min, or 15.24 m/min. For a 10 mm drill, the arithmetic gives approximately 485 RPM before the spindle cap. This page does not interpret a stainless designation as a complete tooling recommendation.

Check the stock condition and the drill supplier’s application data. Replace the starting cutting speed where a specific tool, coating, coolant arrangement, or operation calls for another value. A smaller bit needs more RPM for the same surface speed, but the available machine speed remains a separate constraint.

Do not confuse RPM with feed. The feed calculation needs the axial advance per revolution and uses the actual spindle speed. If the machine cannot hold the selected feed or speed, the calculated values do not establish a workable process. Keep the setup sheet tied to the chosen tool and measured hole requirement.

Calculating drill RPM from diameter and material

For a drill diameter D in millimeters and cutting speed V in meters per minute, RPM is 1000 × V ÷ (π × D). A larger drill needs a lower RPM to keep the same speed at its outer edge. Choose the work material, enter the drill diameter, and check the calculated speed against the speeds available on your machine.

When to enter your own cutting speed

The material presets are starting values for the stated tool basis, not recommendations for every drill. Use the tool manufacturer's data for a coated, carbide, indexable, or otherwise specialized drill. Deep holes, interrupted cuts, poor support, and limited coolant may need a different process.

Feed and drilling time

Feed per revolution describes how far the drill advances in one turn. Multiplying it by RPM gives feed per minute. The drilling-time estimate covers the entered cutting travel; pecking, retracts, approach moves, and handling add time. Do not treat that estimate as a complete production cycle.

Moving from a calculated speed to a machine setting

For a 10 mm drill and a chosen cutting speed of 20 m/min, the equation gives about 637 RPM. At the same cutting speed, a 20 mm drill requires about 318 RPM. Diameter is in the denominator, so doubling diameter halves RPM. These examples use an assumed cutting speed to illustrate the relationship, not a material-specific recommendation.

A stepped-speed drill press may not offer the exact calculated RPM. Choose a setting using the tool and machine guidance, then use the surface-speed mode to see what that setting actually produces. If a drilling feed of 0.1 mm per revolution is used at 600 RPM, feed is 60 mm/min. A 30 mm cutting travel would take half a minute at that steady feed. The drill point, breakthrough, peck cycles, and approach allowance can change the travel or elapsed time needed. Record the selected machine speed rather than retaining an unattainable theoretical RPM in a job setup sheet.

Formula

RPM = 1000Vc/(πD). Feed = RPM × feed/rev; milling multiplies chip load by flute count.

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