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SM2-Compatible Rotation Mounts
Swivel Mount for
Ø2" Rotation Mount
Ø2" Rotation Mount for
This page is a compilation of all of the SM2 (2.035"-40) threaded rotation mounts. Thorlabs also has a similar compilations of SM threaded rotation mounts for Ø1/2" (12.7 mm) and Ø1" (50.8 mm) optics. For our entire selection of rotation mounts, please see the Rotation Mounts and Stages tab.
SM2-Threaded components are designed to mount or integrate Ø2" (50.8 mm) optics into optical systems. These SM2-threaded rotation mounts allow for the 360° degree rotation positioning of the optic.
Thorlabs introduced the SM Series Threading standards to ensure compatibility over a broad range of product lines. SM Series Threaded components offer a simple and efficient solution for building optomechanical structures. The SM Threaded products available, including lens tubes and cage system components, fixed and kinematic mounts, irises and diaphragms, provide flexibility when constructing complex optical systems. Please see the Threading Specs tab for more information on Thorlabs' SM thread standards.
Thorlabs' Threading Specifications
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.
Rotation Mount and Stage Selection Guide
Thorlabs offers a wide variety of manual and motorized rotation mounts and stages. Rotation mounts are designed with an inner bore to mount a Ø1/2", Ø1", or Ø2" optic, while rotation stages are designed with mounting taps to attach a variety of components or systems. Motorized options are powered by a DC Servo motor, 2 phase stepper motor, or an Elliptec™ resonant piezo motor. Each offers 360° of continuous rotation.
Manual Rotation Mounts
Manual Rotation Stages
Motorized Rotation Mounts and Stages
The RSP2(/M) Continuous Rotation Mount utilizes two precision bearings for smooth rotation. The aperture features internal SM2 (2.035"-40) threading and accepts Ø2" optics up to 0.51" (13 mm) thick as well as any SM2-threaded component. Secure the optic using the included SM2RR retaining ring.
The mount has a knurled edge for rotation. A 360° laser-engraved scale marked at 2° increments allows for precise, repeatable positioning and fine angular adjustment. A top-located setscrew can be tightened with a 5/64" (2.0 mm) hex key or balldriver to lock the rotation of the mount.
The RSP2D(/M) Ø2" Continuous Rotation Mount offers the same features as the RSP2 featured above but also incorporates a rotatable dial that can be used, for example, to align a wave plate's optical axis after mounting. Like the RSP2(/M) above, this mount utilizes two precision bearings for smooth, backlash-free rotation. The aperture is threaded with our internal SM2 threading (2.035"-40) and accepts Ø2" optics up to 0.54" (13.7 mm) thick. Secure the optic's position using the included SM2RR retaining ring. The SM2 threading also provides a means to connect SM2 lens tubes and other Thorlabs components to the mount.
This mount has a 360° laser-engraved scale marked at 2° increments to allow for precise, repeatable positioning and fine angular adjustment. The front dial scale can be unlocked and rotated using a 5/64" (2.0 mm) hex key so that the scale can be aligned to the axis of an optic for calibration purposes. A top-located setscrew can be tightened with a 5/64" (2.0 mm) hex key or balldriver to lock the rotation of the mount.
The PRM2(/M) high-precision rotation mount for Ø2" optics combines 360° of continuous coarse manual rotation with precise, backlash-free micrometer adjustment. The SM2-threaded (2.035"-40) inner bore accepts Ø2" optics up to 0.48" (12.2 mm) thick as well as any of our SM2-threaded components. Optics are secured with one SM2RR retaining ring (included with each mount).
The rotation dial face features a laser-engraved scale marked at 1° increments and can be rotated manually using the knurled outer surface (see drawing to the right). The thumbscrew, located on the lower right side of the mount, locks the dial face and engages the micrometer for fine adjustment. When locked, the micrometer provides ±7° of rotation at approximately 2.4 arcmin per micrometer division. This rotation mount also features a 0.05" hex setscrew on both sides that can lock both the fine and coarse rotational movement.
The PRM2(/M) is also compatible with our 60 mm cage system. The cage system can be mounted to the unit using ER cage assembly rods attached to the four 4-40 tapped holes located on the rotation dial face or the four 4-40 tapped holes located on the back side of the mount. The cage system attached to the back of the mount does not rotate.
The LCRM2 rotation mount is designed to mount Ø2" (Ø50.8 mm) optics up to 13 mm (0.51") thick in a 60 mm cage system. The optic is secured using the included SM2RR retaining ring (the SPW604 spanner wrench is ideal for tightening this retaining ring). For thicker optics, any of our SM2 lens tubes can be threaded into the carriage. The smooth rotation mechanism allows for precise positioning of the rotation carriage. The mount features a bottom-located 8-32 (M4) tapped mounting hole for post mounting, making it compatible with our Ø1/2" posts.
The LM2-A optic carriage can be nested inside of the LM2-B (LM2-B/M) mounting ring and offers 360° of continuous rotation for Ø2" optics. The optic bore of each carriage features internal SM2 (2.035"-40) threading and can hold an optic up to 0.46" (11.7 mm) thick with the included SM2RR retaining ring an optic in an SM2-threaded housing. The carriage attaches to the main body of the mount using a thumbscrew. To remove the carriage from the mount, simply loosen the thumbscrew. Extra LM2-A interchangeable rotating carriages are available to allow optics to be swapped out quickly at easily.
Each carriage has a 360° laser-engraved scale marked at 2° increments for precise, repeatable positioning. The top-located thumbscrew can be tightened to lock the rotation of the optic carriage and, along with the double bore on the mount, maintains a stable, three-point contact to hold the optic carriage. When the LM2-A is properly fastened in the LM2-B by the thumbscrew, the optic axis is 1.45" (36.8 mm for the LM2-B/M) above the top of the post.
The LC1A(/M) Swivel Mount is ideal for building spectrometers or other prism- and grating-based systems that require arbitrary angular alignment. The swivel plates are internally threaded for compatibility with our SM2 (2.035"-40) Series of Lens Tubes. In addition, the plates and mounting platform of the LC1A(/M) are independently lockable.
6-Axis Kinematic Mount Usage
The K6X2 6-Axis Kinematic Optic Mount is designed as a general-purpose, high-precision positioner. The optic cell can be translated along or rotated about 6 axes, and each axis has a locking screw for stability. The mount uses 1/4"-80 adjuster screws for pitch, yaw, and z-axis adjustment, and 3/16"-100 adjuster screws for x- and y-axis adjustment.
The translating cell has SM2 (2.035"-40) threading for attaching Ø2" lens tubes or mounting Ø2" (50 mm) optics up to 0.53" (13.4 mm) thick using the included SM2RR Retaining Ring, which can be tightened using an SPW604 Spanner Wrench (sold separately). In testing, the X and Y axes of the K6X2 caused less than ±35 µm of crosstalk.