Optical Component Threading Adapters with SM2 (2.035"-40) Threads


  • Integrate SM2-Threaded Components with Other Industry-Standard Threads
  • Adapters Available with Either Internal or
    External SM2 Threads

SM2L10

SM2A30

BE03-UVB

SM2A30 Adapter
Connecting an
SM2 Lens Tube
to a 3X Galilean
Beam Expander

SM2A6

External SM2 Threads
and Internal SM1 Threads

SM2T2

External SM2 Threads
with Locking Nuts

SM2A23

External M32 x 0.75 Threads
and Internal SM2 Threads

M2M40S

External SM2 Threads and
Internal M40 x 0.706 Threads

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Interactive Selection Guide

SM2-Threaded Optical Component Adapters

This page contains all of our Optical Component Thread Adapters that feature SM2 (2.035"-40) threading. Adapters that have both internal and external threads are available, as well as adapters with two sets of internal or external threads.

Our SM2 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 SM2 and Internal Industry-Standard Threads
Item # Typical Application External Threads Internal Threads
SM2A32
info
Integrate RMS Objective
into SM2 Lens Tube
SM2 (2.035"-40) RMS (0.800"-36)
SM2A33
info
Integrate M25 x 0.75 Objective
into SM2 Lens Tube
SM2 (2.035"-40) M25 x 0.75
GCMA1 info Integrate M25 x 0.75 Scan Lens
into Galvo Mirror Mounting Adapter
SM2 (2.035"-40) M25 x 0.75
SM2A54
info
Mount Camera Lens to
SM2 Lens Tube
SM2 (2.035"-40) C-Mount
(1.00"-32)
SM2A6
info
Step Up/Down Lens Tube Size SM2 (2.035"-40) SM1 (1.035"-40)
SM2A11
info
Step Up/Down Lens Tube Size SM2 (2.035"-40) SM30
(M30.5 x 0.5)
SM2A22
info
Integrate M32 x 0.75 Objective into
SM2 Lens Tube
SM2 (2.035"-40) M32 x 0.75
M2M32S info Integrate M32 x 0.75 Objective
with SM2 Mount
SM2 (2.035"-40) M32 x 0.75
M2M34S info Integrate M34 x 1.0 Objective
with SM2 Mount
SM2 (2.035"-40) M34 x 1.0
SM2A20
info
Integrate Infinity-Corrected Lens Tube
to SM2 Lens Tube
SM2 (2.035"-40) M38 x 0.5
SM2A29
info
Integrate M39-Threaded Scan Lenses
to SM2 Lens Tube
SM2 (2.035"-40) M39 x 1.0
M2M40S info Integrate M40 x 0.706 Objective
with SM2 Mount
SM2 (2.035"-40) M40 x 0.706
SM2A57 info Step Up/Down Lens Tube Size SM2 (2.035"-40) SM1.5 (1.535"-40)
TMA3
info
Mount Camera Lens to
SM2 Lens Tube
SM2 (2.035"-40) T-Mount
(M42 x 0.75)
SM2A24
info
Mount Camera Lens to
SM2 Lens Tube
SM2 (2.035"-40) M42 x 1.0
SM2A30 Adapt M43 x 0.5 Component
to SM2 Lens Tube
SM2 (2.035"-40) M43 x 0.5
SM2A27
info
Mount Camera Lens to
SM2 Lens Tube
SM2 (2.035"-40) M49 x 0.75
SM2A52
info
Mount Camera Lens to
SM2 Lens Tube
SM2 (2.035"-40) M52 x 0.75
SM3A2
info
Step Up/Down Lens Tube Size SM2 (2.035"-40) SM3 (3.035"-40)
Adapters with Internal SM2 and External Industry-Standard Threads
Item # Typical Application External Threads Internal Threads
SM2A31
info
Mount SM2 Lens Tube
to Camera with C-Mount Thread
C-Mount (1.00"-32) SM2 (2.035"-40)
SM1A2
info
Step Up/Down Lens Tube Size SM1 (1.035"-40) SM2 (2.035"-40)
SM2A12
info
Step Up/Down Lens Tube Size SM30
(M30.5 x 0.5)
SM2 (2.035"-40)
SM2A23
info
Integrate SM2 Lens Tube into
M32 x 0.75 Mount
M32 x 0.75 SM2 (2.035"-40)
SM2A19
info
Adapt M36 x 1.5 Threaded Component to SM2 Lens Tube M36 x 1.5 SM2 (2.035"-40)
SM2A58 info Step Up/Down Lens Tube Size SM1.5 (1.535"-40) SM2 (2.035"-40)
TMA4
info
Mount Camera Body to
SM2 Lens Tube
T-Mount
(M42 x 0.75)
SM2 (2.035"-40)
SM2A25
info
Mount Camera Body to
SM2 Lens Tube
M42 x 1.0 SM2 (2.035"-40)
SM2A26
info
Mount Camera Body to
SM2 Lens Tube
M49 x 0.75 SM2 (2.035"-40)
SM2A53
info
Mount Camera Body to
SM2 Lens Tube
M52 x 0.75 SM2 (2.035"-40)
SM2A28
info
Mount M54 x 0.75 Components to an SM2 Lens Tube M54 x 0.75 SM2 (2.035"-40)
SM3A3
info
Step Up/Down Lens Tube Size SM3 (3.035"-40) SM2 (2.035"-40)
Adapter with Internal SM2 and Internal Industry-Standard Threads
Item # Typical Application Internal Threads Internal Threads
SM2T1
info
Mate Two Externally Threaded
SM2 Lens Tubes
SM2 (2.035"-40) SM2 (2.035"-40)
Adapter with External SM2 and External Industry-Standard Threads
Item # Typical Application External Threads External Threads
SM2A55
info
Mount Camera to
SM2 Lens Tube
SM2 (2.035"-40) C-Mount
(1.00"-32)
SM2T2
info
Mate Two Internally-Threaded
SM2 Lens Tubes
SM2 (2.035"-40) SM2 (2.035"-40)

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"

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Adapters with External SM2 (2.035"-40) 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
SM2A32 Support Documentation
SM2A32Adapter with External SM2 Threads and Internal RMS Threads
$27.59
Today
SM2A33 Support Documentation
SM2A33Adapter with External SM2 Threads and Internal M25 x 0.75 Threads
$27.59
7-10 Days
GCMA1 Support Documentation
GCMA1Adapter with External SM2 Threads and Internal M25 x 0.75 Threads, Ø35.0 mm Counterbore
$54.11
Today
SM2A54 Support Documentation
SM2A54Customer Inspired! Adapter with External SM2 Threads and Internal C-Mount Threads, 5.1 mm Long
$26.51
7-10 Days
SM2A6 Support Documentation
SM2A6Adapter with External SM2 Threads and Internal SM1 Threads
$26.51
Today
SM2A11 Support Documentation
SM2A11Customer Inspired! Adapter with External SM2 Threads and Internal SM30 Threads
$24.35
Today
SM2A22 Support Documentation
SM2A22Customer Inspired! Adapter with External SM2 Threads and Internal M32 x 0.75 Threads
$24.35
Today
M2M32S Support Documentation
M2M32SCustomer Inspired! Brass Microscope Adapter with External SM2 Threads and Internal M32 x 0.75 Threads
$53.05
Today
M2M34S Support Documentation
M2M34SCustomer Inspired! Brass Microscope Adapter with External SM2 Threads and Internal M34 x 1.0 Threads
$53.05
Today
SM2A20 Support Documentation
SM2A20Adapter with External SM2 Threads and Internal M38 x 0.5 Threads
$50.40
Today
SM2A57 Support Documentation
SM2A57Adapter with External SM2 Threads and Internal SM1.5 Threads
$24.72
Today
SM2A29 Support Documentation
SM2A29Adapter with External SM2 Threads and Internal M39 x 1.0 Threads
$35.78
Today
TMA3 Support Documentation
TMA3Customer Inspired! Adapter with External SM2 to Internal T-Mount
$24.35
Today
M2M40S Support Documentation
M2M40SCustomer Inspired! Brass Microscope Adapter with External SM2 Threads and Internal M40 x 0.706 Threads
$53.05
Today
SM2A24 Support Documentation
SM2A24Adapter with External SM2 Threads and Internal M42 x 1.0 Threads
$24.35
Today
SM2A30 Support Documentation
SM2A30Adapter with External SM2 Threads and Internal M43 x 0.5 Threads
$16.56
Today
SM2A27 Support Documentation
SM2A27Customer Inspired! Adapter with External SM2 Threads and Internal M49 x 0.75 Threads
$31.12
Today
SM2A52 Support Documentation
SM2A52Adapter with External SM2 Threads and Internal M52 x 0.75 Threads
$21.54
Today
SM3A2 Support Documentation
SM3A2Adapter with External SM2 Threads and Internal SM3 Threads
$32.20
7-10 Days

Adapters with Internal SM2 (2.035"-40) 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
SM2A31 Support Documentation
SM2A31Adapter with External C-Mount Threads and Internal SM2 Threads, 4.9 mm Spacer
$27.59
Today
SM1A2 Support Documentation
SM1A2Adapter with External SM1 Threads and Internal SM2 Threads
$26.51
7-10 Days
SM2A12 Support Documentation
SM2A12Customer Inspired! Adapter with External SM30 Threads and Internal SM2 Threads
$31.12
Today
SM2A23 Support Documentation
SM2A23Customer Inspired! Adapter with External M32 x 0.75 Threads and Internal SM2 Threads
$24.35
Today
SM2A19 Support Documentation
SM2A19Adapter with External M36x1.5 Threads and Internal SM2 Threads
$32.20
Today
SM2A58 Support Documentation
SM2A58Adapter with External SM1.5 and Internal SM2 Threads
$24.72
Today
TMA4 Support Documentation
TMA4Customer Inspired! Adapter with External T-Mount to Internal SM2
$24.35
Today
SM2A25 Support Documentation
SM2A25Adapter with External M42 x 1.0 Threads and Internal SM2 Threads
$24.35
Today
SM2A26 Support Documentation
SM2A26Customer Inspired! Adapter with External M49 x 0.75 Threads and Internal SM2 Threads
$31.12
Today
SM2A53 Support Documentation
SM2A53Adapter with External M52 x 0.75 Threads and Internal SM2 Threads
$21.54
Today
SM2A28 Support Documentation
SM2A28Customer Inspired! Adapter with External M54 x 0.75 Threads and Internal SM2 Threads
$31.12
Today
SM3A3 Support Documentation
SM3A3Customer Inspired! Adapter with External SM3 Threads and Internal SM2 Threads
$32.20
Today

Adapters with External SM2 (2.035"-40) 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
SM2A55 Support Documentation
SM2A55Adapter with External C-Mount Threads and External SM2 Threads, 3.2 mm Spacer
$28.95
7-10 Days
SM2T2 Support Documentation
SM2T2SM2 (2.035"-40) Coupler, External Threads, 1/2" Long
$37.61
Lead Time

Adapter with Internal SM2 (2.035"-40) 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
SM2T1 Support Documentation
SM2T1SM2 (2.035"-40) Coupler, Internal Threads
$19.91
Today