Page 43 - Threading_Handbook

Example for Anvil Selection According to the Following Data

• External right-hand thread
• Threading profile: ISO standard
• Thread diameters: Major diameter: Ø20 mm, effective diameter: Ø18.376 mm
• No. of starts: 1 THREAD TURNING
• Pitch: 2.5 mm

• Holder: SER 2020 K16
• Insert: 16ER 2.50 ISO IC908
• Thread Turning Method: Right-hand threading with right hand holder

Helix Angle Calculation (φ°) by Formula Helix Angle Area From the Graph
5°4° 3°
3
(
φ=arctan P ) 2.5 2°
π×D pitch
2
(
φ=arctan 2.5 ) Lead [mm] 1.5 1°
π×18.376
1
φ≈2.5° or 0.5

0
0 10 20 Diameter [mm]
When:
φ = Helix angle 2°<φ≤3° 18.376
Dpitch = 18.376 mm
P = 2.5 mm
π ≈ 3.142

Recommendation for an Inclination Angle (β°) According to the Thread Turning
Method Definition and Threading Standard
• Inclination Angle (β°) for symmetric profile according to the ISO threading standard for
right-hand threading production with a right-hand holder and obtained helix angle (φ)
• Defined inclination angle: β=2.5 for range of helix angle 2°<φ≤3°

Thread Turning Method
Production of right-hand threading Production of left-hand threading
with right-hand holder with left-hand holder
LH

RH or LH
RH

Anvil Selection
Threading Helix φ (φL)≥5º 4º≤φ (φL)<5º 3º<φ (φL)≤4º 2º<φ (φL)≤3º 1º<φ (φL)≤2º 0º<φ (φL)≤1º
(Lead) Angle φ (φL)
Inclination Angle β 4.5º 3.5º 2.5º 1.5º (std) 0.5º

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