Page 210 - Parlec Catalog

PC Connection

208 Selection Guide

Shank Extension Insert Holder

Insert

Boring Head

Reduction

The force Fr is created by tightening the PC screw. This results in line contact seating with high repeatable
precision (.0002" on diameter). The geometry of the screw and mating hole in the male pilot creates the
resultant force Fa.

Fa = 3.7 x Fr

The face to face clamping forces Fa' are equal to the axial force Fa.

The torsional cutting forces are primarily transmitted by the friction between the mating faces. Any
remaining torque will result in an additional wedge action between the locking screw and the inner member.
Due to the very small resulting wedge angle any increased torsional force Ft will be transformed into a very
strong axial clamping force Fa2.

The cross pin (not shown) helps in alignment of the PC screw and prevents over tightening under heavy
torsional loads.

CONNECTION DIAMETER Fa' Fa'
Fa'
PC Size Diameter " MM Ft
PC2 .94 24
PC3 1.22 31
PC4 1.54 39 Fr'
PC5 1.97 50
PC6 2.52 64 Fa' Fa2
PC7 3.54 90

PC SCREWS

Part Number Connection Size Wrench Tightening Torque
880-002 PC2 018-102 25 in. lbs.
880-003 PC3 018-103 42 in. lbs.
880-004 PC4 018-104 84 in. lbs.
880-005 PC5 018-105 168 in. lbs.
880-006 PC6 018-106 336 in. lbs.
880-007 PC7 018-107 840 in. lbs.
PC Screw 880-006 shown here.

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