777 Segment Bender
Greenlee Textron Inc. / Subsidiary of Textron Inc. 4455 Boeing Dr., Rockford, IL 61109 815-397-7070
9
Laying Out Offset Bends
Calculating “Shrink”
When making offsets, it is common practice to make the
offset as close to the obstruction as possible. When
laying out an offset and working away from an obstruc-
tion, no special provisions are required. However, when
approaching an obstruction, the conduit “shrinks.”
To get the second bend closer to the obstruction, both
bends must be adjusted forward. The amount of this
adjustment is referred to as
shrink
. The following illustra-
tion shows the same installation with shrink factored in.
To find the center-to-center distance and the amount of
shrink per inch of depth for a particular offset, consult the
Greenlee Offset Multiplier and Shrink Table.
Example: 6-inch offset
30-degree bend
Multiplier for 30
°
:2
Multiply the amount of
offset by the multiplier to
find the center-to-center
distance: 2 x 6 = 12
Find the amount of shrink
per inch of offset in the table: 1/4"
Multiply the shrink per inch
by the amount of the offset: 6 x 1/4" = 1.5 inches
Mark the conduit: Place the second bending
mark 1.5 inches past the
obstruction; measure back
toward the starting point
and place the first bending
mark 12 inches before the
second bending mark.
To use this table: Determine the depth of the offset
and the degree of bend. Calculate the center-to-center
distance by multiplying the amount of the offset by the
multiplier (center column). Calculate the amount of
shrink by multiplying the shrink per inch of offset depth
(rightmost column) by the offset depth.
Greenlee Offset Multiplier and Shrink Table
SHRINK PER INCH OF
OFFSET ANGLE MULTIPLIER OFFSET DEPTH
10˚ 6.0 1/16"
15˚ 3.86 1/8"
22-1/2˚ 2.6 3/16"
30˚ 2.0 1/4"
45˚ 1.4 3/8"
60˚ 1.2 1/2"
6
6
CENTER-TO-CENTER
DISTANCE IS 12 INCHES
Second bending mark
is 1.5 inches past
the obstruction
{
CENTER-TO-CENTER DISTANCE
SHRINK
{
Bending marks have been moved forward
Second bend is closer to the obstruction
{
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