KEVOS® MAKEOS · Manufacturing
Grinding Wheel Life and Removal Rate Plan (Taylor Line at an Equivalent Chip Thickness, Shop Calibration)
For grinding at a chosen equivalent chip thickness, what wheel speed gives the wheel life I want, what specific removal rate and work speed follow, how long does a pass take, and how do I correct the standard Taylor constant with one result from my own shop?
Grinding data by the handbook’s machinability system: each material group has Taylor lines V × T^0.26 = C at four equivalent chip thicknesses (ECT), so the wheel speed for a desired wheel life is V = C ÷ T^0.26, the specific metal removal rate SMRR = 1000 × ECT × V mm³ per mm of wheel width per minute, and the work speed Vw = SMRR ÷ (1000 × radial depth). One shop result (wheel speed VU and wheel life TU at a known ECT) gives the user constant CU = VU × TU^0.26 and the ratio CU ÷ C that corrects the standard constant at the other chip thicknesses. Wheel and work rpm, side feed (fraction of wheel width), feed rate, removal rate and grinding time per pass with spark-out complete the plan, checked against the maximum speed marked on the wheel.
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How this tool works
Inputs, units and where to find them
| Input | Unit | Typical source |
|---|---|---|
| Standard Taylor constant C at the chosen ECT (from the material group table) | m/min | Taylor constant C (the wheel speed for 1 minute wheel life) for the material group at the chosen ECT, from the handbook’s grinding data tables or your own data. |
| Equivalent chip thickness chosen | mm | Equivalent chip thickness: the handbook tables use 0.00017, 0.00033, 0.00050 and 0.00075 mm for steels and cast iron, and smaller values for carbide and ceramics with diamond wheels. |
| Wheel life wanted | min | Wheel life between dressings you want, in minutes of grinding. |
| Shop calibration | ||
| Calibrate with a shop result | choice | Whether to correct the standard constant with one result from your own grinding. |
| Shop wheel speed VU | m/min | Wheel speed used in your shop result. |
| Shop wheel life TU | min | Wheel life obtained in your shop result. |
| Standard constant C at the ECT of the shop result | m/min | Standard Taylor constant C from the table at the ECT of your shop result (the same as above when the ECT is the same). |
| Set-up | ||
| Radial depth of cut ar | mm | Radial depth of cut per pass; the handbook gives 0.01 to 0.025 mm for roughing and about 0.0025 mm for finishing. |
| Wheel diameter | mm | Diameter of the grinding wheel. |
| Work diameter (cylindrical grinding) | mm | Diameter of the work in cylindrical grinding. |
| Wheel width | mm | Width of the grinding wheel face. |
| Side feed as a fraction of wheel width C | Side feed per work revolution as a fraction of the wheel width; the handbook lists about 1/2 to 3/4 for roughing and 1/4 to 3/8 for finishing. | |
| Grinding distance per pass | mm | Length ground in one pass. |
| Spark-out time per pass | min | Spark-out time added to each pass. |
| Maximum operating speed marked on the wheel | m/s | Maximum operating speed marked on the wheel. |
What each input means
Open an input to see what it is, its units, the worked example and the common mistakes, with a small diagram.
What this means: Standard Taylor constant C at the chosen ECT (f…
- What it is
- Taylor constant for the work material group at the chosen chip thickness: the wheel speed for 1 minute wheel life.
- Units and format
- Enter a number in m/min: metres per minute. The form accepts 0.000001 m/min to 100000 m/min. Required: the tool does not calculate until every input is valid.
- Example
- The form opens with 4690 m/min as a worked example. It is an illustration, not a recommended value: replace it with your own figure.
- Effect on the result
- Every wheel speed and removal rate is proportional to it.
- Get it right
- Read it from the grinding data table for the material group, or use your calibrated value.
What this means: Equivalent chip thickness chosen
- What it is
- Equivalent chip thickness: work speed × depth ÷ wheel speed, the chip load on the wheel.
- Units and format
- Enter a number in mm: millimetres. The form accepts 0.000005 mm to 0.01 mm. Required: the tool does not calculate until every input is valid.
- Example
- The form opens with 0.00033 mm as a worked example. It is an illustration, not a recommended value: replace it with your own figure.
- Effect on the result
- A larger ECT raises the removal rate at a given wheel speed.
- Get it right
- Tables use 0.00017 to 0.00075 mm for steels; carbide and ceramics with diamond wheels use 0.00002 to 0.00008 mm.
What this means: Wheel life wanted
- What it is
- Wheel life between dressings you want, in minutes of grinding.
- Units and format
- Enter a number in min: minutes. The form accepts 0.000001 min to 100000 min. Required: the tool does not calculate until every input is valid.
- Example
- The form opens with 15 min as a worked example. It is an illustration, not a recommended value: replace it with your own figure.
- Effect on the result
- A longer life lowers the wheel speed and the removal rate.
- Get it right
- Use the dressing interval your process can tolerate.
Shop calibration
What this means: Calibrate with a shop result
- What it is
- Whether the standard Taylor constant is corrected with one result from your own grinding.
- Units and format
- Choose one of 2 options from the list: No: use the standard constant; Yes: one shop result.
- Example
- The form opens with “No: use the standard constant” selected as a worked example. Choose the option that matches your case.
- Effect on the result
- Scales every speed by the calibration ratio.
- Get it right
- Use a recent result on the same machine and wheel type.
What this means: Shop wheel speed VU
- What it is
- Wheel speed at which your shop result was obtained.
- Units and format
- Enter a number in m/min: metres per minute. The form accepts 0.000001 m/min to 100000 m/min. Required: the tool does not calculate until every input is valid.
- Example
- The form opens with 1800 m/min as a worked example. It is an illustration, not a recommended value: replace it with your own figure.
- Effect on the result
- Raises the user constant in proportion.
- Get it right
- Use the speed at the wheel face, not the spindle rpm.
What this means: Shop wheel life TU
- What it is
- Wheel life obtained in your shop result, in minutes of grinding between dressings.
- Units and format
- Enter a number in min: minutes. The form accepts 0.000001 min to 100000 min. Required: the tool does not calculate until every input is valid.
- Example
- The form opens with 7 min as a worked example. It is an illustration, not a recommended value: replace it with your own figure.
- Effect on the result
- A longer life raises the user constant.
- Get it right
- Time only the grinding, not loading or measuring.
What this means: Standard constant C at the ECT of the shop resu…
- What it is
- Standard Taylor constant from the table at the chip thickness of your shop result.
- Units and format
- Enter a number in m/min: metres per minute. The form accepts 0.000001 m/min to 100000 m/min. Required: the tool does not calculate until every input is valid.
- Example
- The form opens with 5290 m/min as a worked example. It is an illustration, not a recommended value: replace it with your own figure.
- Effect on the result
- The calibration ratio is the user constant divided by this.
- Get it right
- Equal to the constant above when the shop result was at the same chip thickness.
Set-up
What this means: Radial depth of cut ar
- What it is
- Radial depth of cut taken by the wheel per pass.
- Units and format
- Enter a number in mm: millimetres. The form accepts 0.000001 mm to 5 mm. Required: the tool does not calculate until every input is valid.
- Example
- The form opens with 0.01 mm as a worked example. It is an illustration, not a recommended value: replace it with your own figure.
- Effect on the result
- A smaller depth needs a faster work speed for the same removal rate.
- Get it right
- About 0.01 to 0.025 mm roughing and 0.0025 mm finishing.
What this means: Wheel diameter
- What it is
- Outside diameter of the grinding wheel.
- Units and format
- Enter a number in mm: millimetres. The form accepts 0.000001 mm to 3000 mm. Required: the tool does not calculate until every input is valid.
- Example
- The form opens with 400 mm as a worked example. It is an illustration, not a recommended value: replace it with your own figure.
- Effect on the result
- Sets the wheel rpm for the wheel speed.
- Get it right
- Measure after dressing; it shrinks with use.
What this means: Work diameter (cylindrical grinding)
- What it is
- Diameter of the work being ground in cylindrical grinding.
- Units and format
- Enter a number in mm: millimetres. The form accepts 0.000001 mm to 3000 mm. Required: the tool does not calculate until every input is valid.
- Example
- The form opens with 50 mm as a worked example. It is an illustration, not a recommended value: replace it with your own figure.
- Effect on the result
- Sets the work rpm for the work speed.
- Get it right
- Use the diameter before the final pass.
What this means: Wheel width
- What it is
- Width of the grinding wheel face.
- Units and format
- Enter a number in mm: millimetres. The form accepts 0.000001 mm to 1000 mm. Required: the tool does not calculate until every input is valid.
- Example
- The form opens with 40 mm as a worked example. It is an illustration, not a recommended value: replace it with your own figure.
- Effect on the result
- With the fraction, sets the side feed.
- Get it right
- Measure the usable face after dressing.
What this means: Side feed as a fraction of wheel width C
- What it is
- Side feed per work revolution as a fraction of the wheel width.
- Units and format
- Enter a plain number with no unit. The form accepts 0.000001 to 1. Required: the tool does not calculate until every input is valid.
- Example
- The form opens with 0.5 as a worked example. It is an illustration, not a recommended value: replace it with your own figure.
- Effect on the result
- Raises the feed rate and removal rate.
- Get it right
- About 1/2 to 3/4 for roughing and 1/4 to 3/8 for finishing.
What this means: Grinding distance per pass
- What it is
- Length ground in one pass of the wheel along the work.
- Units and format
- Enter a number in mm: millimetres. The form accepts 0.000001 mm to 100000 mm. Required: the tool does not calculate until every input is valid.
- Example
- The form opens with 200 mm as a worked example. It is an illustration, not a recommended value: replace it with your own figure.
- Effect on the result
- The time per pass rises in proportion.
- Get it right
- Include the overrun at each end.
What this means: Spark-out time per pass
- What it is
- Spark-out time added to each pass with no further infeed.
- Units and format
- Enter a number in min: minutes. The form accepts 0 min to 100 min. Required: the tool does not calculate until every input is valid.
- Example
- The form opens with 0.05 min as a worked example. It is an illustration, not a recommended value: replace it with your own figure.
- Effect on the result
- Adds directly to the time per pass.
- Get it right
- Zero for roughing passes without spark-out.
What this means: Maximum operating speed marked on the wheel
- What it is
- Maximum operating speed marked on the grinding wheel.
- Units and format
- Enter a number in m/s: metres per second. The form accepts 0.000001 m/s to 300 m/s. Required: the tool does not calculate until every input is valid.
- Example
- The form opens with 45 m/s as a worked example. It is an illustration, not a recommended value: replace it with your own figure.
- Effect on the result
- Fails the plan when the wheel speed is higher.
- Get it right
- Read it from the wheel blotter or label; never exceed it.
Method and formulas
- Taylor line V × T^0.26 = C, so V = C ÷ T^0.26; V10 = C ÷ 10^0.26 and V100 = C ÷ 100^0.26.
- Shop calibration: CU = VU × TU^0.26; ratio = CU ÷ C(standard at the shop ECT); calibrated constant at the chosen ECT = C × ratio.
- SMRR = 1000 × ECT × V (mm³/mm/min); Vw = SMRR ÷ (1000 × ar) (m/min); ECT ≈ Vw × ar ÷ V.
- Wheel rpm = 1000 V ÷ (π D); work rpm = 1000 Vw ÷ (π dw); side feed fs = fraction × width; feed rate FR = fs × work rpm; MRR = SMRR × fs.
- Grinding time per pass = distance ÷ FR + spark-out time.
- Example: with C = 4690 at ECT 0.00033 mm, a 15 min wheel life needs 2,319.5 m/min wheel speed and gives SMRR 765.43 mm³/mm/min.
Limitations
- The Taylor slope n = 0.26 and the tabulated constants assume good system stiffness; calibrate with your own results.
- ECT below about 0.0001 mm may lie on the wrong side of the tool-life curve for steels.
- The wheel must never run above the speed marked on it, whatever the plan gives.
- Example values are illustrations. Replace them with values for your actual task.
Typical uses
- Choose a wheel speed for a wanted wheel life in production grinding
- Find the work speed and removal rate for roughing and finishing depths
- Calibrate the standard grinding data with one shop result
Who it is for
- Grinding machine setters
- Process engineers
- Production planners
What you get
- Taylor constant used (standard or calibrated) and the calibration ratio
- Wheel speed for the wheel life wanted, and V10 and V100
- Specific metal removal rate SMRR and removal rate
- Work speed and work rpm
- Wheel rpm, side feed and feed rate
- Grinding time per pass
Interpreting the result
- A longer wheel life needs a lower wheel speed and gives a lower removal rate at the same ECT.
- A calibration ratio below 1 means your conditions wear the wheel faster than the standard data.
References
- Machinery’s Handbook, 29th edition (Industrial Press, 2012), printed pp. 1205–1214. Topic reference; no source tables or recommended settings are reproduced.
Learn the Concepts Behind This Tool
These KEVOS® Library readings explain the method this tool uses, with worked examples.
Useful alongside · Library collection
Grinding, honing and lapping: finishing hard parts to tight tolerances
What it covers: How abrasive processes work, how to read a grinding wheel specification, the main grinding methods, honing and lapping, avoiding grinding burn and the design details that make finishing easier.
KEVOS® tools are screening and decision-support utilities. Verify important financial, engineering, safety, legal or operational decisions using appropriate professional standards and your organisation’s approved data.