Drill feed depends on the diameter and the specific drill design. Dormer Pramet’s Force X M catalogue provides a feed-per-revolution chart organized by the product’s Alpha Code and drill diameter. This page reproduces selected chart points so a reader can locate a starting feed quickly. The code must come from the exact drill product page; it is not a generic material label.

Twist Drill Feed Rate by Diameter

Find the Force X M drill’s Alpha Code first, then read the matching diameter and feed per revolution. The values shown are selected entries from the manufacturer chart.

Feed per revolution, fn, is how far the drill advances during one complete spindle rotation. At 6 mm diameter, for instance, Alpha Code J has a listed feed of 0.197 mm/rev, while Alpha Code A is 0.042 mm/rev. The different figures show why diameter alone is not enough. The Alpha Code is part of the tool identification and ties the value to the manufacturer’s product selection.

If the machine requires feed per minute, multiply the feed per revolution by spindle speed. At 0.197 mm/rev and 1,500 rpm, the arithmetic gives 295.5 mm/min. That calculation converts units; it does not independently validate the speed or the operation. Make sure the spindle speed came from the right cutting-speed recommendation for the material and exact drill.

The chart uses specified diameter columns rather than a continuous equation. For a diameter that falls between listed sizes, the manufacturer instructs the user to select the closest diameter for the application. Do not interpolate across a large diameter gap without an engineering basis. The table lists no value for some Alpha Code and diameter combinations; a dash or absent row means there is no published entry to copy.

Dormer Pramet notes that operating conditions may require adjustments of plus or minus 25 percent. This is guidance to evaluate the application, not automatic permission to raise feed by 25 percent. Hole depth, drill projection, material group, hardness, coolant, chip evacuation, machine rigidity and the hole’s exit condition can all affect the stable feed. Use the toolmaker’s product-specific application data and observe the cut.

A common mistake is choosing the Alpha Code from a remembered material mapping. The code should be read from the exact Force X M product details; do not assume one code applies to all drills for the same alloy. Another mistake is treating this feed chart as a cutting-speed chart. It gives millimetres per revolution. Cutting speed and spindle speed must be selected separately from the manufacturer’s relevant speed data.

For a first setup, confirm the drill series, diameter, Alpha Code and hole depth. Select the exact chart entry, then consider a conservative adjustment where the setup is less rigid or chip evacuation is limited. Check the resulting feed in the control’s units. If the control uses inch per revolution, convert carefully and preserve enough precision to avoid rounding a small feed to zero or an unsafe increment.

These selected entries are for the Force X M product family and should not be transferred to conventional HSS drills, other carbide drills or different manufacturers. The chart is a starting recommendation, not a guarantee of tool life, hole finish, positional accuracy or safe spindle load. For a production process, verify the current catalogue revision and qualify the settings on the actual machine, material, coolant and hole geometry.

When the diameter is not one of the displayed examples, return to the complete chart rather than estimating from these sample rows. Keep a copy of the source revision with the setup notes so a later tooling change does not silently inherit the wrong code or feed.

Sources

The source is Dormer Pramet’s Force X M catalogue, feed-rate chart on page 10. It explains the Alpha Code lookup and the possible ±25% adjustment based on working conditions.