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USER GUIDE
THREADING Anvils for Laydown Inserts The anvil should be selected from the table according to

The parameter for tilting the threading insert relative to
the thread ing standard. The correct anvil depends on the
the helix angle of threading is of great importance when
threading is produced. This parameter ensures proper
The inclination angle (β) is obtained by selecting the thread
operation of the insert during threading production in
turning method and finding the helix angle (φ)
terms of equal load distribution applied to the insert,
equal distribution of forces operating on the insert, right inclination angle (β) and insert size. φ
for single-start threading, or lead angle ( L) for the multi-
development of uniform wear on both sides of the cutting start threading.
φ
edge, and avoiding friction of the insert with the side of The helix angle (φ) and the lead angle ( L) are determined
the threading profile. If the side clearance insert angles as exact values by using the formula below or as a
(α) are not equal in relation to the helix angle (φ), the graph area (see below: Helix (Lead) angle area by using
insert must be tilted. This is performed by using anvils. graph, depending on the threading diameter and lead.)
Recommended Less Recommended Helix Angle (φ) Calculation Lead Angle (φL) Calculation
by Using the Single-Start by Using the Single-Start
Threading Formula Threading Formula
αL=αR αL≠αR
Lead

P

φ=arctan ( π×Dpitch ) φ L=arctan ( π×Dpitch )

φ φ
Lead= n×P
β β =0 When: When:
φ = Helix angle φ L = Lead angle
Dpitch = Pitch diameter* Dpitch = Pitch diameter*
α R
α R
α L * effective diameter of threading * effective diameter of threading
α L
P = Threading pitch P = Threading pitch
Quick and easy way to select a correct anvil π ≈ 3.142 n = number of
threading starts
Helix (Lead) Helix (Lead) angle π ≈ 3.142
angle calculation or area from the graph
by formula
Usable Formulas
Recommendation for an inclination Lead (inch)= 1 inch ×No. of starts
TPI
angle (β°) according to the thread
turning method definition and TPI = No. of threading per inch
dependent on the thread standard 1 inch = 25.4 mm
Pitch (mm)= 25.4
TPI
Recommendation for a suitable anvil
according to the insert size and type
of toolholder
(internal or external)

786 ISCAR