Universal Base Plate

  • Center-Located Slot Allows for Rotation and Translation
  • Array of Tapped and Counterbored Holes Allow for a
    Variety of Mounting Options
  • Provides Mounting Holes in Any Orientation on the
    Optical Table


UBP2 Base Plate Can be Used to Roughly Adjust the Spacing
between the Lenses in a Telescope Setup

Related Items

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Universal Base Plate Application
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Centrally Located Slot Allows Mounting of Components Outside of the Standard 1" Hole Pattern
Universal Base Plate Application
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View Imperial Product List
Item #QtyDescription
Imperial Product List
UBP21Universal Base Plate, 2.5" x 2.5" x 3/8"
ER3-P41Cage Assembly Rod, 3" Long, Ø6 mm, 4 Pack
CP331SM1-Threaded 30 mm Cage Plate, 0.35" Thick, 2 Retaining Rings, 8-32 Tap
SH25S05011/4"-20 Stainless Steel Cap Screw, 1/2" Long, 25 Pack
View Metric Product List
Item #QtyDescription
Metric Product List
UBP2/M1Universal Base Plate, 65 mm x 65 mm x 10 mm, Metric
ER3-P41Cage Assembly Rod, 3" Long, Ø6 mm, 4 Pack
CP33/M1SM1-Threaded 30 mm Cage Plate, 0.35" Thick, 2 Retaining Rings, M4 Tap
SH6MS121M6 x 1.0 Stainless Steel Cap Screw, 12 mm Long, 25 Pack
UBP2 Vertically Mounting a
30 mm Cage System
UBP2 Drawing
Click for Details

Mechanical Drawing


  • 1.25" (31.8 mm) Long Counterbored Slot for 1/4" (M6) Cap Screws Allows for Rotation and Translation
  • Tapped Holes:
    • 1/4"-20 (M6) (Qty. 6)
    • 8-32 (M4) (Qty. 16)
    • 4-40 (Qty. 4)
  • Counterbored Holes:
    • 1/4" (M6) (Qty. 4, Two per Side)
    • #8 (M4) (Qty. 4, Two per Side)

The UBP2(/M) Universal Base Plate increases the flexibility of any optical setup by providing mounting holes in virtually any orientation on an optical table or breadboard. This freedom allows users to mount various components or stages in a wide array of orientations outside of what is dictated by the standard 1" (25 mm) hole pattern. The counterbores in the plate also allow one to adapt metric components to an imperial optical table and vice versa.

The plate dimensions are 2.5" x 2.5" x 3/8" for the imperial version or 65 mm x 65 mm x 10 mm for the metric version. The 1.25" (31.8 mm) long counterbored slot for 1/4" (M6) cap screws is centrally located and allows 360° rotation of the plate as well as rough translation on the optical table. An array of 1/4"-20 (M6) and 8-32 (M4) tapped mounting holes are available for mounting components in various orientations, while four 4-40 tapped holes are spaced for compatibility with our 30 mm cage system. Two counterbored holes for both 1/4" (M6) and #8 (M4) cap screws are also located on both sides of the base plate for mounting optical post assemblies.

The counterbored holes for 1/4" (M6) cap screws are located in two corners on each side of the plate and are diagonally across from one another. The counterbored holes for #8 (M4) cap screws are located on the center line perpendicular to the counterbored slot with a spacing of 2" (50 mm) on the top of the plate and 1" (25 mm) on the bottom of the plate. Please see the mechanical drawing above for more details.

Cage System Overview

The Cage Assembly System provides a convenient way to construct large optomechanical systems with an established line of precision-machined building blocks designed for high flexibility and accurate alignment.

16 mm, 30 mm, and 60 mm Cage System Standards

Thorlabs offers three standards defined by the center-to-center spacing of the cage assembly rods (see image below). The 16 mm cage, 30 mm cage, and 60 mm cage standards are designed to accomodate Ø1/2", Ø1", and Ø2" optics, respectively. Specialized cage plates that allow smaller optics to be directly inserted into our larger cage systems are also available.

Standard Threads

The flexibility of our Cage Assembly System stems from well-defined mounting and thread standards designed to directly interface with a wide range of specialized products. The three most prevalent thread standards are our SM05 Series (0.535"-40 thread), SM1 Series (1.035"-40 thread), and SM2 Series (2.035"-40 thread), all of which were defined to house the industry's most common optic sizes. Essential building blocks, such as our popular lens tubes, directly interface to these standards.

An example of the standard cage plate measurements determining cage system compatibility.
Standard Cage System Measurements
Cage System 16 mm 30 mm 60 mm
Thread Series SM05 SM1 SM2
Rod to Rod Spacing 16 mm (0.63") 30 mm (1.18") 60 mm (2.36")
Total Length 25 mm (0.98") 41 mm (1.60") 71.1 mm (2.8")
Cage Components
Cage Rods 16 mm These rods are used to connect cage plates, optic mounts, and other components in the cage system. The SR Series Cage Rods are compatible with our 16 mm cage systems, while the 30 mm and 60 mm cage systems use ER Series Cage Rods.
30 mm
60 mm
Cage Plates 16 mm These serve as the basic building blocks for a cage system. They may have SM-threaded central bores, smooth bores sized for industry standard optics or to accommodate the outer profile of our SM Series Lens Tubes, or specialized bores for other components such as our FiberPorts.
30 mm
60 mm
Optic Mounts 16 mm Thorlabs offers fixed, kinematic, rotation, and translation mounts specifically designed for our Cage Systems.
30 mm
60 mm
Cage Cubes 16 mm These cubes are useful for housing larger optical components, such as prisms or mirrors, or optics that need to sit at an angle to the beam path, such as beamsplitters. Our cage cubes are available empty or with pre-mounted optics.
30 mm
60 mm
Post and Breadboard Mounts and Adapters Mounting options for cage systems can be found on our Cage System Construction pages. Cage Systems can be mounted either parallel or perpendicular to the table surface.
Size Adapters Cage System Size Adapters can be used to integrate components from different cage system and threading standards.
Specialized Components Thorlabs also produces specialized cage components, such as Filter Wheels, a HeNe Laser Mount, and a FiberPort Cage Plate Adapter, allowing a wide range of our products to be integrated into cage-mounted optical systems. Explore our Cage Systems Visual Navigation Guide to see the full range of Thorlabs' cage components.

Posted Comments:
cottsb  (posted 2015-03-05 18:12:15.91)
This baseplate changed my life!
cdaly  (posted 2015-03-10 03:18:21.0)
Response from Chris at Thorlabs: Thank you for the feedback. We are glad to hear it.
Based on your currency / country selection, your order will ship from Newton, New Jersey  
+1 Qty Docs Part Number - Imperial Price Available
UBP2 Support Documentation
UBP2Customer Inspired! Universal Base Plate, 2.5" x 2.5" x 3/8"
+1 Qty Docs Part Number - Metric Price Available
UBP2/M Support Documentation
UBP2/MCustomer Inspired! Universal Base Plate, 65 mm x 65 mm x 10 mm, Metric