Designed for Compatibility with Ø3" (Ø76.2 mm) Optics
Wide Range of SM3-Compatible Optomechanical Components Available
Lens tubes are ideal for creating compact optical subassemblies. The Ø3" lens tubes sold here can be used to house one or several optical elements. Optics are separated and secured by retaining rings that are positioned at the desired depth within the lens tube using a spanner wrench. These stackable lens tubes ship with one retaining ring. Additional retaining rings can be purchased separately. In addition to the Ø3" lens tubes featured on this page, Thorlabs also offers Ø1/2", Ø1", Ø30 mm, Ø1.5", Ø2", and Ø3" versions, each of which is equipped with an SM series thread standard that depends on the tube diameter.
Thorlabs' lens tubes utilize a series of non-standard threadings. Threading specifications are given below for our SM threadings utilized in our lens tube and cage system components so that you can machine mating components to suit your application. We also offer products with C-Mount and RMS threadings, and the specifications for these threadings are also given below. Please note that other manufacturers may have different tolerances for these threads. For other thread specifications that are not listed here, please contact Tech Support.
Stackable Design Enables Multi-Element Optical Systems
Ideal for Large Optical Assemblies
These stackable Ø3" lens tubes provide a fast and easy means for building compact optical assemblies. Their stackable design and direct interfacing with any SM3-threaded (3.035"-40) components provide flexibility for complex optomechanical assemblies. One SM3RR retaining ring is included with each lens tube.
Spanner Wrenches Provide One-Handed Adjustment of SM3RR Retaining Rings
SPW801 Adjustable Spanner Wrench can Accommodate Diameters from 0.12" (3.0 mm) to 2.89" (73.4 mm)
Due to its hollow design, the SPW605 Spanner Wrench enables retaining rings for our SM3 series of lens tubes to be adjusted and installed without obscuring the beam path. The handle is knurled for improved grip. Alternatively, the SPW801 Adjustable Spanner Wrench can also be used to position SM3RR retaining rings. Please note that the SPW801 wrench can withstand a maximum torque of 80 inch pounds. We also offer the SPB3 Spanner Bit, which can be used with a standard 1/4" hex driver (sold separately). The SPB3 is included as part of the SPB600 Spanner Wrench Bit Kit.