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How to Cut a Face Groove on a Lathe
Guide · Updated October 28, 2026
A face groove is cut into the end face of a part, like an O-ring gland on a flange. Unlike an OD groove, the tool travels along the Z axis and the groove is an arc, so the tool needs curved side clearance matched to the groove diameter or it will rub.
Check groove width and depth
Use gage blocks or pin gages to check width and a depth mic for depth. The free Gage Block Calculator builds the stack.
Step by step
- Read the groove size: Inner diameter, outer diameter, width and depth.
- Choose a face grooving tool: Pick a tool whose curvature range covers the groove diameter (often printed on the holder).
- Set tool on center: Off-center face grooving rubs on the inside wall.
- Position the first cut: Touch the face, then position X to the outer diameter of the groove for the first plunge.
- Plunge and peck: Feed in Z at 0.001–0.003 in/rev, pecking to break chips.
- Widen if needed: Step in X and plunge again to widen.
- Finish walls and bottom: Take light finishing cuts and measure.
Worked example
An O-ring face gland with ID 1.500 in and OD 1.750 in: width = (1.750 − 1.500) ÷ 2 = 0.125 in. Using a 0.125 in grooving tool, position its outer corner at 1.750 in diameter in one plunge. At 1.625 in mean diameter and 300 SFM, RPM = 3.82 × 300 ÷ 1.625 = 705 RPM; at 0.002 in/rev the Z feed is 1.4 in/min. For a 0.080 in deep gland, peck in 0.020 in steps: 4 pecks.
Why curvature matters
The groove walls are circles. A straight-sided tool on a small diameter hits the inside wall behind the cutting edge, so face grooving tools are bent to match a diameter range.
Common problems
Rubbing on one wall means the tool curve is wrong for the diameter. Chatter means too much stickout. Packed chips mean no pecking.
Tips
- OD grooves: cut a groove on a lathe.
- Measure: measure a groove with gage blocks.
- Facing: face on a lathe.
FAQ
What is a face groove?
A groove cut into the end face of a part.
Why does my tool rub?
The tool curvature does not match the groove diameter.
Can I use a normal grooving tool?
Only on large diameters where the curve is gentle.
How do I measure a face groove?
Width with gage blocks or pins, depth with a depth mic.
What feed?
About 0.001–0.003 in/rev with pecking.
Related guides and calculators
- How to Cut a Groove on a Lathe
- How to Measure a Groove or Recess with Gage Blocks
- How to Face on a Lathe
- How to Part Off on a Lathe
- How to Set Tool Height on a Lathe
- How to Use a Dead Center
- How to Cut Buttress Threads on a Lathe
- All free machinist calculators
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