Ø1.5" Lens Tubes

  • Lens Tubes Accept Ø1.5" (Ø38.1 mm) Optics
  • Compatible with All SM1.5-Threaded Components
  • Stackable Design Enables Construction of Multi-Element Optical Systems


0.3" Thread Depth


0.5" Thread Depth


1.00" Thread Depth


2.00" Thread Depth


SM1.5 (1.535"-40) Retaining Ring

Related Items

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Lens Tube Engraving
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When an engraved lens tube is attached to another lens tube, the engraving of the connected end is no longer visible.
Additional Lens Tube Sizes
Ø30 mm
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  • Lens Tubes in Lengths from 0.30" (7.6 mm) to 2.00" (50.8 mm)
  • Tubes Directly Accept Ø1.5" (Ø38.1 mm) Optics

Lens tubes are ideal for creating compact optical subassemblies with light-tight beam paths. The Ø1.5" 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. Each stackable lens tube ships with one retaining ring. Additional retaining rings can be purchased separately. In addition to the Ø1.5" lens tubes featured on this page, Thorlabs also offers versions from Ø1/2" to Ø3", each of which is equipped with an SM-series thread standard that depends on the tube diameter. Additional lens tube sizes can be found in the table to the right.

Lens Tube Compatible Products
Terminated Fiber
Fixed Fiber Collimator
Kinematic Fiber Collimator
LED Mounts LD Mounts Aspheric Lens Mounts Irises, Apertures, and Shutters Alignment Tools

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.

SM05 Threading: Ø1/2" Lens Tubes, 16 mm Cage Systems
External Thread, 0.535"-40.0, UNS-2A Internal Thread, 0.535"-40.0, UNS-2B
Max Major Diameter 0.5340" Min Major Diameter 0.5350"
Min Major Diameter 0.5289" Min Pitch Diameter 0.5188"
Max Pitch Diameter 0.5178" Max Pitch Diameter 0.5230"
Min Pitch Diameter 0.5146" Min Minor Diameter (and 83.3% of thread) 0.508"
Max Minor Diameter 0.5069" Max Minor Diameter (and 64.9% of thread) 0.514"
RMS Threading: Objective, Scan, and Tube Lenses
External Thread, 0.800"-36.0, UNS-2A Internal Thread, 0.800"-36.0, UNS-2B
Max Major Diameter 0.7989" Min Major Diameter 0.8000"
Min Major Diameter 0.7934" Min Pitch Diameter 0.7820"
Max Pitch Diameter 0.7809" Max Pitch Diameter 0.7866"
Min Pitch Diameter 0.7774" Min Minor Diameter (and 83.3% of thread) 0.770"
Max Minor Diameter 0.7688" Max Minor Diameter (and 64.9% of thread) 0.777"
C-Mount Threading: Machine Vision Lenses, CCD/CMOS Cameras
External Thread, 1.000"-32.0, UN-2A Internal Thread, 1.000"-32.0, UN-2B
Max Major Diameter 0.9989" Min Major Diameter 1.0000"
Min Major Diameter 0.9929" Min Pitch Diameter 0.9797"
Max Pitch Diameter 0.9786" Max Pitch Diameter 0.9846"
Min Pitch Diameter 0.9748" Min Minor Diameter (and 83.3% of thread) 0.966"
Max Minor Diameter 0.9651" Max Minor Diameter (and 64.9% of thread) 0.974"
SM1 Threading: Ø1" Lens Tubes, 30 mm Cage Systems
External Thread, 1.035"-40.0, UNS-2A Internal Thread, 1.035"-40.0, UNS-2B
Max Major Diameter 1.0339" Min Major Diameter 1.0350"
Min Major Diameter 1.0288" Min Pitch Diameter 1.0188"
Max Pitch Diameter 1.0177" Max Pitch Diameter 1.0234"
Min Pitch Diameter 1.0142" Min Minor Diameter (and 83.3% of thread) 1.008"
Max Minor Diameter 1.0068" Max Minor Diameter (and 64.9% of thread) 1.014"
SM30 Threading: Ø30 mm Lens Tubes
External Thread, M30.5x0.5 Internal Thread, M30.5x0.5
Max Major Diameter 30.480 mm Min Major Diameter 30.500 mm
Min Major Diameter 30.371 mm Min Pitch Diameter 30.175 mm
Max Pitch Diameter 30.155 mm Max Pitch Diameter 30.302 mm
Min Pitch Diameter 30.059 mm Min Minor Diameter (and 83.3% of thread) 29.959 mm
Max Minor Diameter 29.938 mm Max Minor Diameter (and 64.9% of thread) 30.094 mm
SM1.5 Threading: Ø1.5" Lens Tubes
External Thread, 1.535"-40, UNS-2A Internal Thread, 1.535"-40, UNS-2B
Max Major Diameter 1.5339" Min Major Diameter 1.535"
Min Major Diameter 1.5288" Min Pitch Diameter 1.5188"
Max Pitch Diameter 1.5177" Max Pitch Diameter 1.5236"
Min Pitch Diameter 1.5140" Min Minor Diameter (and 83.3% of thread) 1.508"
Max Minor Diameter 1.5068" Max Minor Diameter (and 64.9% of thread) 1.514"
SM2 Threading: Ø2" Lens Tubes, 60 mm Cage Systems
External Thread, 2.035"-40.0, UNS-2A Internal Thread, 2.035"-40.0, UNS-2B
Max Major Diameter 2.0338" Min Major Diameter 2.0350"
Min Major Diameter 2.0287" Min Pitch Diameter 2.0188"
Max Pitch Diameter 2.0176" Max Pitch Diameter 2.0239"
Min Pitch Diameter 2.0137" Min Minor Diameter (and 83.3% of thread) 2.008"
Max Minor Diameter 2.0067" Max Minor Diameter (and 64.9% of thread) 2.014"
SM3 Threading: Ø3" Lens Tubes
External Thread, 3.035"-40.0, UNS-2A Internal Thread, 3.035"-40.0, UNS-2B
Max Major Diameter 3.0337" Min Major Diameter 3.0350"
Min Major Diameter 3.0286" Min Pitch Diameter 3.0188"
Max Pitch Diameter 3.0175" Max Pitch Diameter 3.0242"
Min Pitch Diameter 3.0133" Min Minor Diameter (and 83.3% of thread) 3.008"
Max Minor Diameter 3.0066" Max Minor Diameter (and 64.9% of thread) 3.014"
SM4 Threading: Ø4" Fixed Lens Mounts
External Thread, 4.035"-40.0, UNS-2A Internal Thread, 4.035"-40.0, UNS-2B
Max Major Diameter 4.0337" Min Major Diameter 4.0350"
Min Major Diameter 4.0286" Min Pitch Diameter 4.0188"
Max Pitch Diameter 4.0175" Max Pitch Diameter 4.0245"
Min Pitch Diameter 4.0131" Min Minor Diameter (and 83.3% of thread) 4.008"
Max Minor Diameter 4.0066" Max Minor Diameter (and 64.9% of thread) 4.014"

Posted Comments:
user  (posted 2019-06-17 01:31:08.07)
Will you offer corresponding lens tube mounts (SM1.5 version of the SM1TC) and adapters to SM1 and 2?
llamb  (posted 2019-06-17 05:01:01.0)
Hello, thank you for contacting Thorlabs. We are indeed currently looking into offering thread adapters from SM1.5 to SM1 and SM2 threads. I have added your idea for SM1.5 lens tube mounts to our internal product forum as well. Thanks for the feedback!

Ø1.5" Stackable Lens Tubes

SM1.5Lxx Lens Tube Diagram
  • Stackable Design Enables Multi-Element Optical Systems
  • SM1.5-Threaded (1.535"-40) Bore Accepts Ø1.5" (Ø38.1 mm) Optics

These stackable Ø1.5" lens tubes provide a fast and easy means for building compact optical assemblies. They can directly interface with any SM1.5-threaded (1.535"-40) component to provide flexibility for complex optomechanical systems. One SM1.5RR Retaining Ring is included with each lens tube.

Item # L Internal Thread Depth
SM1.5L03 0.33" (8.4 mm) 0.30" (7.6 mm)
SM1.5L05 0.53" (13.5 mm) 0.50" (12.7 mm)
SM1.5L10 1.03" (26.2 mm) 1.00" (25.4 mm)
SM1.5L20 2.03" (51.6 mm) 2.00" (50.8 mm)

Alternatives Ø1/2", Ø1", Ø30 mm, Ø2", and Ø3" Stackable Lens Tubes
Based on your currency / country selection, your order will ship from Newton, New Jersey  
+1 Qty Docs Part Number - Universal Price Available
SM1.5L03 Support Documentation
SM1.5L03SM1.5 Lens Tube, 0.30" Thread Depth, One Retaining Ring Included
SM1.5L05 Support Documentation
SM1.5L05SM1.5 Lens Tube, 0.50" Thread Depth, One Retaining Ring Included
SM1.5L10 Support Documentation
SM1.5L10SM1.5 Lens Tube, 1.00" Thread Depth, One Retaining Ring Included
5-8 Days
SM1.5L20 Support Documentation
SM1.5L20SM1.5 Lens Tube, 2.00" Thread Depth, One Retaining Ring Included

Ø1.5" Retaining Rings and Spanner Wrenches

  • SM1.5RR Retaining Rings Secure Ø1.5" (Ø38.1 mm) Optics
  • SPW608 Hollow Spanner Wrench Provides Unobstructed Beam Path During Adjustment
  • SPW801 Adjustable Spanner Wrench can Accommodate Diameters from 0.12" (3.0 mm) to 2.89" (73.4 mm)

These Retaining Rings can be used to secure optical components into our SM1.5-threaded (1.535"-40) lens tubes. One retaining ring is included with in the purchase of a lens tube; however, additional rings enable multiple optics to be secured inside the same lens tube. The SPW608 Spanner Wrench or the SPW801 Adjustable Spanner Wrench can be used to position SM1.5RR retaining rings. Please note that the SPW801 wrench can withstand a maximum torque of 80 lb-in. We also offer the SPB1.5 SM1.5 Spanner Bit, which can be used with a standard 1/4" hex driver (sold separately). 

Alternatives Ø1/2", Ø1", Ø2", and Ø3" Spanner Wrenches Ø1/2", Ø1", Ø2", and Ø3" Retaining Rings
Based on your currency / country selection, your order will ship from Newton, New Jersey  
+1 Qty Docs Part Number - Universal Price Available
SM1.5RR Support Documentation
SM1.5RRSM1.5 Retaining Ring for Ø1.5" Lens Tubes and Mounts
SPW608 Support Documentation
SPW608Spanner Wrench for SM1.5-Threaded Retaining Rings, Graduated Scale with 0.02" (0.5 mm) Increments, Length = 3.88"
SPW801 Support Documentation
SPW801Adjustable Spanner Wrench
5-8 Days
SPW102 Support Documentation
SPW102Adjustable Spanner Wrench, Replacement Blade Set