Optical Component Threading Adapters with C-Mount (1.00"-32) Threads


  • Integrate C-Mount Threaded Components with Other Industry-Standard Threads
  • Adapters Available with Either Internal or External C-Mount Threads
  • Mount C-Mount Lenses to CS-Mount Cameras

CML05

5 mm Spacer

SM1A10TS

Thermally Insulating Adapter
with External SM1 Threads
and Internal C-Mount Threads

RMSA5

External C-Mount
Threads and Internal
RMS Threads

CS165MU

SM1A10Z

MVL4WA

SM1A10Z Adapter Connecting an MVL4WA C-Mount Lens to the SM1-Threaded Aperture of a Zelux® Camera

Related Items


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Interactive Selection Guide

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C- vs. CS-Mount Flange Focal Distances


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Spacer Length for the SM1A10Z Adapter

C-Mount Threaded Optical Component Adapters

This page contains all of our Optical Component Thread Adapters that feature C-mount (1.00"-32) threading. Adapters featuring either internal or external threads are available.

The CS- and C-mount standards both use 1.00"-32 threads, but C-mount lenses have a flange focal distance (FFD) that is 5 mm longer than CS-mount lenses, as illustrated in the diagram to the far right. Spacer length is defined for each adapter as the distance depicted by the diagram to the near right. The CML05 adapter is 5 mm long and acts as a spacer, enabling the use of C-mount lenses with CS-mount cameras. These adapters are a subset of our entire line of optical component thread adapters. To view our entire line, please see our Interactive Adapters Selection Guide.

Adapters with External C-Mount (1.00"-32)
and Internal Industry-Standard Threads
Item # Typical Application External Threads Internal Threads
SM05A2
info
Mount a C-Mount Camera Body to an SM05 Lens Tube C-Mount (1.00"-32) SM05 (0.535"-40)
RMSA5
info
Mount RMS Objective to Camera C-Mount (1.00"-32) RMS (0.800"-36)
SM1A9
info
Mount a C-Mount Camera Body to an SM1 Lens Tube C-Mount (1.00"-32) SM1 (1.035"-40)
SM1A9TSa
info
Mount a C-Mount Camera Body to an SM1 Lens Tube C-Mount (1.00"-32) SM1 (1.035"-40)
TMA5
info
Mount a C-Mount Camera Body to a T-Mount Lens C-Mount (1.00"-32) T-Mount (M42 x 0.75)
SM2A31
info
Mount SM2 Lens Tube
to Camera with C-Mount Thread
C-Mount (1.00"-32) SM2 (2.035"-40)
  • Thermally insulating adapter. See the Thermal Insulation tab above for more information.
Adapters with Internal C-Mount (1.00"-32)
and External Industry-Standard Threads
Item # Typical Application External Threads Internal Threads
RMSA6
info
Integrate Camera Lens to Microscope RMS (0.800"-36) C-Mount (1.00"-32)
CML05
info
Mount C-Mount Camera Lens
to CS-Mount Camera
C-Mount (1.00"-32) C-Mount (1.00"-32)
SM1A10
info
Mount CS-Mount Camera Lens to Zelux® Camera SM1 (1.035"-40) C-Mount (1.00"-32)
SM1A10TSa
info
Mount Camera Lens to
SM1 Lens Tube
SM1 (1.035"-40) C-Mount (1.00"-32)
SM1A10A info Mount C-Mount Camera Lens to Kiralux® and Quantalux® Cameras SM1 (1.035"-40) C-Mount (1.00"-32)
DC-CS1
info
Mount Camera Lens to
SM1 Lens Tube
SM1 (1.035"-40) C-Mount (1.00"-32)
SM1A10Zb
info
Mount Camera Lens to
Zelux Camera
SM1 (1.035"-40) C-Mount (1.00"-32)
TMA6
info
Mount Camera Lens to
T-Mount Camera
T-Mount (M42 x 0.75) C-Mount (1.00"-32)
SM2A54
info
Mount Camera Lens to
SM2 Lens Tube
SM2 (2.035"-40) C-Mount (1.00"-32)
  • Thermally insulating adapter. See the Thermal Insulation tab above for more information.
  • This adapter provides the correct flange focal distance for mounting C-mount lenses to our Zelux® cameras. 
Adapters with External C-Mount (1.00"-32)
and External Industry-Standard Threads
Item # Typical Application External Threads Internal Threads
CMT2
info
Mate Two
C-Mount Extension Tubes
C-Mount (1.00"-32) C-Mount (1.00"-32)
CMT10
info
Mate Two
C-Mount Extension Tubes
C-Mount (1.00"-32) C-Mount (1.00"-32)
SM05A1
info
Mount a C-Mount Camera
Body to an SM05 Lens Tube
C-Mount (1.00"-32) SM05 (0.535"-40)
SM1A39
info
Mount a C-Mount Camera
Body to an SM1 Lens Tube
C-Mount (1.00"-32) SM1 (1.035"-40)
SM2A55
info
Mount a C-Mount Camera
Body to an SM2 Lens Tube
C-Mount (1.00"-32) SM2 (2.035"-40)
Adapter with Internal C-Mount (1.00"-32)
and Internal Industry-Standard Threads
Item # Typical Application External Threads External Threads
CMT1
info
Mate Two
C-Mount Extension Tubes
C-Mount (1.00"-32) C-Mount (1.00"-32)
Legend
 Reflectance Heated SM1 Lens Tube with Aluminum Adapter  Reflectance Heated SM1 Lens Tube with Delrin® Adapter
 Reflectance Unheated SM1 Lens Tube with Aluminum Adapter  Reflectance Unheated SM1 Lens Tube with Delrin® Adapter

Thermal Insulation Experiment

An experiment was conducted to compare the thermal isolation of our thermally insulating adapters (SM1A4TS, SM1A9TS, SM1A3TS, and SM1A10TS) presented at the bottom of this page with that of our traditional aluminum adapters. During the experiment, an aluminum adapter and a thermally isolating black Delrin®* adapter were each used to connect two lens tubes. Then, one of the lens tubes was externally heated to 60 °C using a foil heating element that had been attached to that lens tube’s outer surface.

During the heating process, simultaneous temperature readings were recorded in 30 second intervals for both the heated and unheated lens tube in each system. The measured results are shown in the plot to the right. From the graph, it is clearly evident that there is far less heat transfer when using one of our thermally isolating adapters to connect two lens tubes than exists when using an aluminum adapter.

*Delrin® is a registered trademark of DuPont Polymers, Inc.

Selection Guide for Thermally Insulating Adapters
Item # Adapter Profile External Threads Internal Threads
SM1A4TS  icon RMS (0.800"-36) SM1 (1.035"-40)
SM1A9TS  icon C-Mount (1.00"-32) SM1 (1.035"-40)
SM1A3TS  icon SM1 (1.035"-40) RMS (0.800"-36)
SM1A10TS  icon SM1 (1.035"-40) C-Mount (1.00"-32)

Threading Specifications

The following is a general overview of screw threading. For more details regarding specifications and dimensions, please consult the Machinery's Handbook, available for purchase at many bookstores.

Features of a Thread
A thread consists of three repeating features: a crest, flank, and root (see drawing to the right). Except in special cases, threads have symmetrical sides inclined at equal angles when a vertical line is drawn through the center of a crest or root. The distance between corresponding points on adjacent threads is known as the pitch of the thread. The flank angle is defined as the angle the flank makes with a perpendicular ray drawn from the screw axis. Unless otherwise stated, threads have a flank angle of 30°, resulting in a total angle between flanks of 60°. Each feature is shown in the diagram to the right.

The major diameter is taken from the crests of a thread while the minor diameter is taken from the roots. For most screws, crests and roots do not terminate at a sharp point, so crest and root truncation values are included in the definitions of major and minor diameter. The pitch diameter is approximately halfway between the major and minor diameters.

Thread Form
A thread form is a set of rules that define the features' scale relative to one another. Common thread forms include the Unified Screw Thread Form, used in the United States of America and measured in imperial units, and the ISO Metric Screw Thread Form, used in many parts of the world and measured with the International System of Units. There are many thread forms in the Unified screw thread standard designated by either UN, which defines a flat root contour, or UNR, which defines a round root contour. These can be further described by appending more letters. For example, an extremely fine thread with a flat root contour is designated UNEF. Those forms which are not standardized by the Unified screw thread system are designated UNS.

Thread Series
Most screws are identified by their thread series. Thread series are denoted by the major diameter and density of threads. Unified threads specify density in threads per inch, while Metric threads specify the thread pitch. For example, in the Unified nomenclature, a 1/4"-20 cap screw has a 1/4" diameter barrel and the pitch is 20 threads per inch (TPI). In metric nomenclature, an M4 x 0.7 cap screw has a 4 mm barrel and the pitch is 1 thread per 0.7 mm. The term M4 x 0.7 is often shortened to just M4.

Unified Thread Class Tolerancing
Location Loose Optimal Strict
Internal 1B 2B 3B
External 1A 2A 3A
Metric Thread Tolerance Positions
Location Loose Optimal Strict
Internal - G H
External e or f g h
Metric Thread Tolerance Grades
Dimension Location Tolerance Gradesa
Minor Diameter Internal 4, 5, 6, 7, 8
Major Diameter External 4, 6, 8
Pitch Diameter Internal 4, 5, 6, 7, 8
External 3, 4, 5, 6, 7, 8, 9
  • The tolerance becomes looser as the grade increases. The underlined grades are used with normal lengths of thread engagement.

Thread Class
The tolerances and allowances on a thread series are given by a thread class. Unified thread classes are alphanumeric identifiers starting with a number from 1 through 3, where 1 is the loosest tolerance and 3 is the tightest, and either A for external threading or B for internal threading.

Metric threads have a slightly more complex tolerancing method that uses tolerancing grades, designated by a number 3 through 9; and tolerancing positions, which use letters e through h. Grades provide a measure of the tolerance itself: the smaller the number, the tighter the tolerance. Positions denote the distance of the tolerance from the pitch diameter. Uppercase positioning letters indicate internal threads while lowercase positioning letters indicate external threads.

Quoting from the Machinery's Handbook, 29th Edition, p. 1885: "To designate the tolerance class, the grade and position of the pitch diameter is shown first followed by that for the major diameter in the case of the external thread or that for the minor diameter in the case of the internal thread, thus 4g6g for an external thread and 5H6H for an internal thread. If the two grades and positions are identical, it is not necessary to repeat the symbols, thus 4g, alone, stands for 4g4g and 5H, alone, stands for 5H5H."

Thorlabs' SM Series Threads
Threading specifications for our SM threads, utilized in our lens tube and cage system components, are given below so that you can machine mating components to suit your application. Most SM series threads utilize a non-standard Unified thread form, indicated by the letters UNS, with a 30° flank angle and a thread class of 2A and 2B. The exception is our SM30 series thread, which is a Metric thread form with a 30° flank angle and a tolerance of 6H/6g. We also offer products with C-Mount and RMS threads, and the specifications for these threads are given below for reference. Please note that other manufacturers may have different tolerances for C-Mount and RMS 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, M30.5 x 0.5 – 6H/6g Internal Thread, M30.5 x 0.5 – 6H/6g
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" Lens Tubes
External Thread, 4.035"-40 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 2019-09-12 11:26:28.347)
I suggest that you consider releasing a modified "customer-inspired" version of this part. Increase the OD to 2 inches, smooth or SM2 thread, and you've got yourself a camera with a lens, perfectly mounted and aligned inside a 2" lens tube. A slotted lens tube comes in very handy to turn focusing and iris rings on the lens. (In order to do it now, I had shave off the knurled surface on CML05, then it can go into CP12, then shave off corners of the CP12 so that it can go inside 2" lens tube.)
llamb  (posted 2019-09-12 05:19:41.0)
Thank you for your feedback. We will consider this new product suggestion. Perhaps you can also consider our SM2A54 adapter to achieve a similar function for mounting C-Mounted threaded camera lenses inside an SM2 lens tube. I have reached out to you directly to discuss your application further.
user  (posted 2019-06-17 15:40:15.657)
My application needs 1.042-32 (dia and thread) . I could not find one in your inventory that matches my need. The closest I get is SM05A2 which is 1.000-32. I am wondering if a piece of my spec can me made as a customer inspired product. If so how much may be the unit price. Thanks in advance for your time. Regards Radha K Pattnaik
YLohia  (posted 2019-06-17 04:16:53.0)
Hello Radha, thank you for contacting Thorlabs. Custom items can be requested by emailing your local Thorlabs Technical Support team. I'm reaching out to you directly to discuss the possibility of offering this.
user  (posted 2015-10-20 09:12:42.373)
It would also be nice to have a SM05 to M12 adapter (lenses with an M12 thread seem common for small USB cameras).
besembeson  (posted 2015-10-27 06:42:26.0)
Response from Bweh at Thorlabs USA. Thanks for your feedback. We will review this suggestion for S-mount (M12x0.5) adapters which is relevant for board-level integration of small lenses and small USB cameras like you mentioned.

5 mm Spacer with C-Mount (1.00"-32) Threads

The CML05 adapter has C-mount (1.00"-32) threads and adds 5 mm between a lens and a camera when mounted. Used as a spacer, it enables the use of C-mount lenses with CS-mount cameras.

Based on your currency / country selection, your order will ship from Newton, New Jersey  
+1 Qty Docs Part Number - Universal Price Available
CML05 Support Documentation
CML05CS- to C-Mount Extension Adapter, 1.00"-32 Threaded, 5 mm Spacer
$18.92
Today

Adapters with External C-Mount (1.00"-32) and Internal Industry-Standard Threads

Based on your currency / country selection, your order will ship from Newton, New Jersey  
+1 Qty Docs Part Number - Universal Price Available
SM05A2 Support Documentation
SM05A2Adapter with External C-Mount Threads and Internal SM05 Threads, 3.8 mm Long
$21.51
Today
RMSA5 Support Documentation
RMSA5Customer Inspired! Adapter with External C-Mount Threads and Internal RMS Threads, 5.1 mm Long
$20.67
Today
SM1A9 Support Documentation
SM1A9Adapter with External C-Mount Threads and Internal SM1 Threads, 4.4 mm Spacer
$19.96
Today
SM1A9TS Support Documentation
SM1A9TSCustomer Inspired! Thermally Insulating Adapter with External C-Mount Threads and Internal SM1 Threads, 6.5 mm Spacer
$23.61
Today
TMA5 Support Documentation
TMA5Customer Inspired! Adapter with External C-Mount Threads and Internal T-Mount Threads, 4.3 mm Spacer
$24.96
Today
SM2A31 Support Documentation
SM2A31Adapter with External C-Mount Threads and Internal SM2 Threads, 4.9 mm Spacer
$28.28
Today

Adapters with Internal C-Mount (1.00"-32) and External Industry-Standard Threads

Based on your currency / country selection, your order will ship from Newton, New Jersey  
+1 Qty Docs Part Number - Universal Price Available
RMSA6 Support Documentation
RMSA6Customer Inspired! Adapter with External RMS Threads and Internal C-Mount Threads, 4.6 mm Spacer
$21.51
Today
SM1A10 Support Documentation
SM1A10Adapter with External SM1 Threads and Internal C-Mount Threads, 4.1 mm Spacer
$20.78
Today
SM1A10TS Support Documentation
SM1A10TSCustomer Inspired! Thermally Insulating Adapter with External SM1 Threads and Internal C-Mount Threads, 6.5 mm Spacer
$23.61
Today
SM1A10A Support Documentation
SM1A10AAdapter with External SM1 Threads and Internal C-Mount Threads, 6.9 - 8.9 mm Spacer
$33.83
Today
DC-CS1 Support Documentation
DC-CS1Adapter with External SM1 Threads and Internal C-Mount Threads, 7.42 mm Spacer
$30.23
Today
SM1A10Z Support Documentation
SM1A10ZAdapter with External SM1 Threads and Internal C-Mount Threads, 9.1 mm Spacer
$24.60
Today
TMA6 Support Documentation
TMA6Customer Inspired! Adapter with Internal C-Mount Threads and External T-Mount Threads, 5.1 mm Long
$24.96
Today
SM2A54 Support Documentation
SM2A54Customer Inspired! Adapter with External SM2 Threads and Internal C-Mount Threads, 5.1 mm Long
$27.17
Today

Adapters with External C-Mount (1.00"-32) and External Industry-Standard Threads

Based on your currency / country selection, your order will ship from Newton, New Jersey  
+1 Qty Docs Part Number - Universal Price Available
SM05A1 Support Documentation
SM05A1Customer Inspired! Adapter with External C-Mount Threads and External SM05 Threads, 2.6 mm Spacer
$21.51
Today
CMT2 Support Documentation
CMT2C-Mount (1.00"-32) Coupler, External Threads, 0.5" Long
$22.08
Today
CMT10 Support Documentation
CMT10C-Mount (1.00"-32) Coupler, External Threads, 1" Long
$22.62
Today
SM1A39 Support Documentation
SM1A39Customer Inspired! Adapter with External C-Mount Threads and External SM1 Threads, 3.2 mm Spacer
$21.21
Today
SM2A55 Support Documentation
SM2A55Adapter with External C-Mount Threads and External SM2 Threads, 3.2 mm Spacer
$29.67
Today

Adapters with Internal C-Mount (1.00"-32) and Internal Industry-Standard Threads

Based on your currency / country selection, your order will ship from Newton, New Jersey  
+1 Qty Docs Part Number - Universal Price Available
CMT1 Support Documentation
CMT1C-Mount (1.00"-32) Coupler, Internal Threads
$10.87
Today