Steel drilling and reaming data are useful only when the tool, work material, and operation match the source recommendation. Manufacturer examples show why one speed and feed should not be presented as a universal setting for “steel.” Dormer Pramet reports separate drilling cases for a C40 quenched-steel component and a 42CrMo4 bearing ring, each using a named modular drill. Kennametal publishes a separate product-specific recommendation for a solid-carbide reamer. Keep those cases distinct and verify the current catalog before applying them.

Steel Drilling and Reaming Cutting Data

Selected drilling and reaming cases

The first drilling case uses Dormer Pramet tool RP81017.5 on C40 quenched steel at 230 HB, in a 5×D drilling application with coolant. The stated parameters are 90 m/min and 0.20 mm/rev. A second case uses RP93019.3 on 42CrMo4 at 290 HB, also drilling 5×D with coolant; the listed values are 80 m/min and 0.32 mm/rev. The reaming row comes from a different manufacturer product: KenReam S102, grade KC6305, for its ISO P1 material group. Its displayed speed and feed are a conversion of the supplier’s starting values for the four-flute reamer.

Convert cutting speed to rpm

Cutting speed Vc is the circumferential speed at the tool edge, usually expressed in metres per minute. For a tool diameter D in millimetres, spindle speed n in revolutions per minute is 1000Vc divided by pi times D. For example, the 90 m/min drilling case at a 10 mm drill diameter calculates to about 2,865 rpm. This is a conversion example, not a second Dormer recommendation for a 10 mm version of the product. Confirm that the exact tool diameter is available and supported by its manufacturer data.

Keep drilling feed and reaming feed separate

Drill feed is normally specified per revolution. Feed rate in millimetres per minute is feed per revolution multiplied by spindle speed. A reamer catalog may instead give feed per tooth; multiply by flute count to derive feed per revolution, preserving the source’s actual diameter band and unit. The example in the table converts 0.002 inch per tooth across four flutes to 0.2032 mm per revolution. Verify that the source defines the recommendation for the stated material group and tool geometry before using the conversion. Do not apply a milling feed-per-tooth formula to a twist drill.

Select the material group carefully

Steel designations and hardness are not interchangeable labels. C40 at 230 HB and 42CrMo4 at 290 HB are different work materials and the examples use different product codes. Heat treatment, hardness, stock condition, interrupted entry, hole depth, chip evacuation, tool coating, and coolant supply can all move a practical setting away from a starting value. The ISO P1 category on the reamer page is the manufacturer’s classification group, not a steel grade. Read the product maker’s material-group definition and confirm the alloy and condition fit that category.

Common mistakes and checks

A frequent mistake is to copy one cutting speed into a chart for every drill in the same diameter range. The manufacturer guidance explains that tool substrate, coating, work material, diameter, and stability affect the recommendation. Another mistake is to calculate rpm correctly but overlook feed, depth, coolant, or whether a value is for drilling or reaming. Before cutting, identify the tool code and grade, match the steel and hardness, verify hole depth and coolant, compute rpm and feed rate with consistent units, then inspect chips, torque, finish, and tool condition. Follow the current tool maker’s application guidance and machine limits.

What these examples do not guarantee

The entries are examples from two manufacturers and use different tools and test or application contexts. They are starting data, not production guarantees, safe limits, or a substitute for a current tool catalog. One Dormer case reports a customer result; that result does not establish performance on another machine or component. The KenReam selected product page may change as product ranges are updated. Check its present availability and application table before selecting a tool. For a released process plan, have a qualified manufacturing engineer confirm tool choice, workholding, machine power, coolant, chip control, and required hole quality.

Sources and verification

Drilling examples and operation context: Dormer Pramet Modular Drills (2026). Reaming data: Kennametal KenReam S102 product 7029804. The maker explains the input dependence in its cutting-data guide.

This table is a reference aid, not a substitute for the governing design code, product specification, qualified engineering review, or measurements from the actual component and service conditions.