Carbide drills often operate in a different parameter range from HSS drills, but the RPM and feed formulas are unchanged. The important part is selecting the correct source data for the actual carbide drill series, workpiece material, point geometry, coating and hole depth before using the calculator.
Use the spindle-speed calculator to translate the recommended cutting speed into RPM. Then use feed per revolution to turn the manufacturer’s feed value into the linear feed expected by the CNC. For deep holes, through-coolant and chip evacuation can be more important than a small mathematical difference in RPM.
Basic calculation first. Advanced check second.
Run the simple relationship first, then use the advanced version when the operation needs more variables or machine constraints. The calculators are intentionally stacked, not side by side.
Basic Carbide drilling Speed & Feed Calculator
Run the core calculation for this machining workflow.
Spindle Speed Basic
Enter the values you know. The result is calculated in your browser.
Calculation only. Verify toolmaker data, material grade, engagement, machine limits, workholding and actual cutting conditions before production.
Advanced Carbide drilling Speed & Feed Calculator
Add the relevant process or machine variables for a fuller calculation.
Feed Per Rev Advanced
Enter the values you know. The result is calculated in your browser.
Calculation only. Verify toolmaker data, material grade, engagement, machine limits, workholding and actual cutting conditions before production.
What this carbide drill speed and feed calculator calculates
Record drill diameter, cutting speed, feed per revolution, drill grade/coating, workpiece material and hole depth. Also note whether the carbide drill is intended for through-coolant and what entry condition it expects. Carbide tools can be less forgiving of runout and instability than a slower HSS process.
Formulas and unit handling
Carbide drilling still uses RPM = (1000 × Vc) ÷ (π × D) or the imperial equivalent. Feed is RPM × feed/rev. What changes is the input range: carbide drill data must be taken from the toolmaker and matched to the actual material and drill series.
RPM = (1000 × Vc) ÷ (π × D).Use the source unit shown in your tooling reference before converting.RPM = (12 × SFM) ÷ (π × D).Use the source unit shown in your tooling reference before converting.Feed = RPM × feed per revolution.Use the source unit shown in your tooling reference before converting.Feed/rev = feed ÷ RPM.Use the source unit shown in your tooling reference before converting.Step-by-step workflow
Technical context for this search
Solid-carbide drilling should not be reduced to “use a higher speed.” Carbide drill recommendations can depend on grade, point geometry, coolant delivery, hole depth and machine stability. This page uses the standard RPM and feed-per-revolution relationships while making the tool-specific boundaries explicit.
Carbide drills can run at conditions that are inappropriate for HSS tools, but the machine and process must support them. Through-coolant, spindle runout, rigid workholding and suitable chip evacuation can be important parts of the manufacturer recommendation. If those conditions are missing, simply selecting the numerical midpoint of a catalog range may be the wrong starting point.
Diameter still controls RPM through the same surface-speed relationship. When a carbide drill is changed from one diameter to another, recalculate RPM even if the material and coolant remain the same. Then check the manufacturer’s feed range for that diameter rather than assuming the old mm/rev value scales automatically.
For first-piece validation, watch entry stability, chip evacuation, hole straightness, load and tool wear. Carbide can fail abruptly when runout or instability is excessive, so a clean first-hole check is valuable. Keep the exact drill number and coolant condition in the production record.
Calculation audit checklist
| Check | What to verify |
|---|---|
| Operation check | Confirm that the job is actually carbide drilling before entering values. The calculator pair on this page was selected for the carbide drill speed and feed calculator search intent, so switching to another operation may require a different feed convention. |
| Source check | Use the exact tooling or process reference behind carbide drill speed and feed calculator. Record the tool or process identifier, material and source units before converting anything; the site calculates from supplied values rather than selecting proprietary cutting data. |
| Input check | Verify the primary inputs used by the spindle-speed and feed-per-rev calculators. A field can be numerically valid while still being the wrong variable for the operation, especially when moving between chip load, feed/rev, feed rate and surface speed. |
| Unit check | Keep metric and imperial values separated through the calculation. Recheck diameter, cutting speed and feed units on the Carbide Drill Speed and Feed Calculator page before accepting the result, and only round after the relationship has been verified. |
| Machine check | Compare the theoretical output with machine spindle, feed, travel and process limits. A calculated value is not a machine capability statement, and a controller limit can make the effective cutting condition different from the selected target. |
| Tool/setup check | Review tool condition, runout, overhang, workholding and coolant or lubrication where relevant to carbide drilling. These variables are outside the arithmetic model but can dominate the actual cutting result. |
| First-cut check | Treat the first part or first hole as a validation event. Record chips, sound, load, finish and dimensional result alongside the calculated RPM/feed so later changes can be traced to evidence rather than memory. |
| Recordkeeping check | For repeat work, save the source reference, selected inputs, calculated values and final programmed values together. The Carbide Drill Speed and Feed Calculator calculation then becomes a reproducible setup record instead of a one-time online number. |
Worked example
A 10 mm carbide drill at 120 m/min gives about 3,820 RPM. At 0.12 mm/rev the feed is about 458 mm/min. Whether that is appropriate depends on the drill design and material; the example demonstrates the conversion rather than a universal carbide drilling recommendation.
Practical setup checks
Carbide drill stability is critical because brittle cutting edges can be damaged by runout, interrupted entry or poor chip evacuation. Verify the holder and spindle runout, workpiece support and coolant delivery before increasing the condition. A machine that can reach the calculated RPM is not automatically a machine that can run the complete hole safely at that feed.
Common mistakes
- Using HSS data for a carbide drill.
- Ignoring tool runout.
- Assuming carbide automatically means “faster is always better.”
- Skipping coolant verification on a tool that expects through-coolant.
- Using the drill’s nominal diameter without checking the exact series.
Troubleshooting the calculated condition
For edge chipping, inspect runout and entry stability. For heat or galling, inspect cutting speed and coolant. For chip packing, review hole depth and evacuation. For oversize holes, check runout, drill point condition and spindle alignment before changing the nominal speed/feed values.
How to cross-check tool data
Use the carbide drill manufacturer’s exact series data. This page should be treated as the conversion and verification layer, not the source of proprietary cutting recommendations.
Frequently asked questions
Does carbide change the RPM formula?
No. The formula is the same; the recommended cutting-speed range is what changes.
Why is carbide drilling more sensitive to runout?
Carbide cutting edges can be less tolerant of unstable loading and uneven edge engagement, so runout becomes an important process variable.
Is through-coolant always required?
Not for every carbide drill, but many designs and deep-hole conditions depend heavily on coolant delivery. Check the toolmaker’s instructions.
Can I use the calculator for any carbide drill?
The math applies broadly, but the actual cutting inputs must match the exact drill series and material.
This page calculates relationships from the values supplied by the user. It does not inspect the machine, tool condition, workholding or material state. Verify production cutting values against the exact tooling reference and the actual setup before running the cut.