Design, Manufacture and Installation of Theatrical Equipment Worldwide

Recommended Mounting Dimensions

Underhung Head Block: Single Beam
Upright Head Bock: Double Beam
Floor Mounted Lock Rail
Underhung Head Block: Double Beam
Arbor Pit Mounted Lock Rail
DimDescriptionValue
AWall Clearance3" MIN
(7.6 cm)
BBeam Spacing18 - 22"
(45.7 - 55.9 cm)
CWall to Face of
T or J Guide
8 - 20"
(20 - 50.4 cm)
DFace of T or J Guide
to Center of Arbor
7-7/8" (200 mm)
EClearance of Handlines
to Adjacent Structures
3 - 5"
(7.6 - 12.7 cm)
FFace of T or J Guide
to Edge of
Loading Gallery
22 - 25"
(55.9 - 63.5 cm)
GLiftline/Loft Block
Beam Spacing
10' MAX
(3 m)
HFace of T or J to
Edge of Beam
Flange of Offstage
Head Beam
5" MAX
(12.7 cm)
JB.O.S. Head Block
Beam to Top
of Guide
18" MIN
(45.7 cm)
KWall to Center
of Single Head
Block Beam
19-1/2" MIN
(49.5 cm)
LT.O.S. Head Block
Beam to Blocks
B.O.S. Loft Block
Beams
16" for 12"
(40.6 for 30.5 cm)
Head Blocks
12" for 8"
(30.5 for 20 cm)
Loft Blocks
MFloor to Top
of Lockrail
27-1/2" (70 cm)
NFace of T or J Guide
to Back of Lockrail
24" (61 cm)
OFloor to Top of the
Bottom Arbor Stop
24" MIN
(61 cm)
PWall to Edge of
Arbor Pit Opening
= N + C
QFace of T or J Guide
to Arbor Pit Wall
36" MIN
(91.5 cm)
7041 Interstate Island Road | Syracuse, NY USA 13209-9713 | Phone: 315-451-3440 | Toll Free: 800-836-1885
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