Page 39 - Threading_Handbook

Anvil Selection for Symmetric Threading Profiles
The table below defines the recommended insert inclination angle (β) and anvil selection
according to the helix angle (φ) for single-start threading and the lead angle (φL) for
multi-start threading, depending on the threading turning method for machining the following
symmetric threading profiles:

• partial profile threading with angle profile of 60°, 55° only THREAD TURNING
• full profile threading according to ISO, UN, Whitworth, NPT,
BSPT, Trapeze, ACME, RD standards only

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

or
RH LH
RH

Anvil Selection
Positive Anvils

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

IC Toolholder Anvil Designation
16 EX RH OR IN LH AE 16+4.5 AE 16+3.5 AE 16+2.5 * AE 16+1.5 AE 16+0.5
(3/8) EX RH OR IN LH AI 16+4.5 AI 16-3.5 AI 16+2.5 * AI 16+1.5 AI 16+0.5

22 EX RH OR IN LH AE 22+4.5 AE 22+3.5 AE 22+2.5 * AE 22+1.5 AE 22+0.5
(1/2) EX RH OR IN LH AI 22+4.5 AI 22+3.5 AI 22+2.5 * AI 22+1.5 AI 22+0.5

27 EX RH OR IN LH special AE 27-4.5 AE 27+3.5 AE 27+2.5 * AE 27+1.5 AE 27+0.5
(5/8) EX RH OR IN LH solution AI 27+4.5 AI 27+3.5 AI 27+2.5 * AI 27+1.5 AI 27+0.5

22U EX RH OR IN LH AE 22U+4.5 AE 22U+3.5 AE 22U+2.5 * AE 22U+1.5 AE 22U+0.5
(1/2U) EX RH OR IN LH AI 22U+4.5 AI 22U+3.5 AI 22U+2.5 * AI 22U+1.5 AI 22U+0.5
27U EX RH OR IN LH AE 27U+4.5 AE 27U+3.5 AE 27U+2.5 * AE 27U+1.5 AE 27U+0.5
(5/8U) EX RH OR IN LH AI 27U+4.5 AI 27U+3.5 AI 27U+2.5 * AI 27U+1.5 AI 27U+0.5

* Standard anvil supplied with tool
Positive Anvils

Feed Towards the Chuck

+φ (φ L)
+β

1.5°
const.

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