Lever-Actuated, SM-Threaded Iris Diaphragms


  • Compatible with Our Lens Tubes
  • Standard Lever Activation
  • Zero-Aperture and Stainless Steel Models Available

SM1D25

Internally
SM1-Threaded Iris

SM2D25

SM2-Threaded Iris

SM1D12SS

SM1-Threaded
Stainless Steel Iris

SM1D12

SM1-Threaded Iris

SM1L03

Lens Tube

SM1RC

Lens Tube
Slip Ring

Application Idea

Related Items


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Iris Selection Guide
Post-Mountable Irises
Unmounted Irises
SM-Threaded, Lever-Actuated Irises
SM-Threaded, Ring-Actuated Irises
Cage System Irises

Features

  • Lever-Actuated Design
  • SM1D12SS Iris with Stainless Steel Leaves for High-Power Applications
  • SM1D12SZ Iris with Zero Aperture Blocks All Incoming Light in Closed Position

Thorlabs offers lever-activated irises with compatible lens tube threading for use with our lens tube systems, SM-threaded mounts, and cage systems.

In addition, Thorlabs offers a line of Post-Mountable Irises, SM-Threaded Ring-Actuated Irises, Unmounted Irises, and Cage System Irises as well as mounted pinholes and slits.

Item # SM05D5 SM1D12 SM1D25 SM1D12SS SM1D12SZ SM2D25 SM3D50
Type Lever Actuated Lever Actuated Lever Actuated Lever Actuated,
Stainless Steel
Lever Actuated,
Zero Aperture
Lever Actuated Lever Actuated
Thread Standard SM05 (0.535"-40) SM1 (1.035"-40) SM1 (1.035"-40) SM1 (1.035"-40) SM1 (1.035"-40) SM2 (2.035"-40) SM3 (3.035"-40)
Aperture (Min) Ø0.7 mm Ø0.8 mm Ø1 mm Ø1 mm Zero Ø1 mm Ø2 mm
Aperture (Max) Ø5 mm Ø12 mm Ø25 mm Ø11.9 mm Ø11.9 mm Ø25 mm Ø50 mm

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:
Rick Young  (posted 2019-06-20 18:36:19.34)
Where is the 'plane' of the iris/aperture itself referenced to whatever (one side)? None of the drawings I looked at specify this measurement ...!
YLohia  (posted 2019-06-21 11:27:56.0)
Hello, thank you for contacting Thorlabs. The distance between the surface of the externally SM2 threaded side and the iris plane is 4.75mm for the SM2D25. This information can be found in the Solidworks model.
user  (posted 2019-04-04 05:41:59.82)
Hi, We recently purchased two of these irises from you. We don't seem to be able to use the locking screw to stop the lever from moving once it's in the position we want. We tried a variety of allen keys and the one that best fit was 0.03in/0.75mm. We tried looking at the CAD drawing but all it says is "locking screw". Could you tell me what the correct allen key should be? Thanks, Chris
mmcclure  (posted 2019-04-04 08:12:07.0)
Hello, thank you for your question. The setscrew located on the housing of each iris is not a locking mechanism. Rather, this setscrew helps to hold the internal aperture mechanism within the mounting ring. We will provide this information on the webpage presentation to avoid future confusion.
user  (posted 2017-03-22 13:50:34.42)
Irises with max apertures of 75mm and 100mm would be very useful.
swick  (posted 2017-03-23 05:20:25.0)
This is a response from Sebastian at Thorlabs. Thank you for the inquiry. We offer irises with max. aperture 75mm. The item name would be ID75Z: https://www.thorlabs.com/newgrouppage9.cfm?objectgroup_id=206 At the time we do not offer an iris with aperture of 100mm as standard item. I would like to check if we can offer a customized version for you. As you did not left any contact details, please contact techsupport@thorlabs.com
syim  (posted 2016-05-13 16:02:46.317)
Hello, It would be helpful that you have zero aperture iris of 25 mm max aperture diameter. Could I get a custom item?
shallwig  (posted 2016-05-13 08:34:48.0)
This is a response from Stefan at Thorlabs. Thank you very much for your inquiry, we offer zero aperture post mounted Iris diaphragms with 25mm max aperture (ID25Z) and our standard Iris diaphragms without mounting holes are also available with 25mm max aperture, the part number is D25SZ. I have contacted you directly to check if one of these is suitable for you.
ludoangot  (posted 2016-02-17 09:30:00.037)
Hello, it would have been good to explicitly specify that for zero aperture irises, the dual leaf design actually means two aperture planes. At least I wasn't aware that your dual leaf design implied there's 2 apertures and they are not coplanar. Such a design is not desired when the location of the aperture plane is critical such as in some telecentric systems.
jlow  (posted 2016-02-25 11:08:41.0)
Response from Jeremy at Thorlabs: Thank you for the feedback. We will make this information clearer on the website.
grovyle  (posted 2015-04-14 13:14:44.963)
I have a SM1T1 stuck on a SM1D12. I want to submerge the whole thing in WD40 and sonicate it. Afterward, rinse it with an organic solvent. I need to know if the iris is only metal or it has plastic parts that can be damaged this way. I tried to lose it mechanically buy can make more pressure without risking destroying the iris or the tube. Do you have any suggestions on how to separate them. I'm deciding between keep trying or just leave the tube permanently stuck on the iris.
shallwig  (posted 2015-04-22 05:37:15.0)
This is a response from Stefan at Thorlabs. Thank you very much for your inquiry. The iris lever is made from stainless steel, the fins are made from hoop steel while the housing is made from anodized aluminum, there are no plastic parts used. There is also grease attached to guarantee smooth aperture settings. Normally it should be possible to lose the SM1D12 from the SM1T1 mechanically, I will contact you directly to troubleshoot this problem in more detail.
tomerg  (posted 2014-05-18 10:12:42.683)
Can you please provide the mechanical tolerance on the external diameter of the SM1D25 iris? its nominal diameter is given (40.6mm) in the drawing, but for my application the tolerance is required as well. Thanks.
cdaly  (posted 2014-05-22 10:55:35.0)
Response from Chris at Thorlabs: Thank you for your inquiry. I will contact you directly with this value.
tomerg  (posted 2014-04-07 08:24:56.213)
Good morning, Regarding the iris SM1D25: is there an option to lock the aperture at a certain opening after initial adjustment? Thanks, Tomer.
cdaly  (posted 2014-04-08 07:44:53.0)
Response from Chris at Thorlabs: Thank you for your inquiry. The SM1D25 aperture does not have a locking mechanism. There is a set screw on the bottom, which looks like it may be, but after inspection of the part, it is clear this is used only for assembly purposes, holding the internal aperture mechanism itself within the mounting ring at a fixed angle.
christophe.yamahata  (posted 2013-12-10 10:33:35.167)
Would it be possible to order iris diaphragms SM05D5 without the Thorlabs marking? The arrow symbol is very useful, but Thorlabs's logo is not desired for our commercial product.
jlow  (posted 2013-12-18 08:47:05.0)
Jeremy Low: Response from Jeremy at Thorlabs: We could definitely do this as a custom for you. I will get in contact with you directly on getting a quote set up.
technicalmarketing  (posted 2008-07-28 22:58:46.0)
Hallo, We will work on new drawings of the Iris Diaphragms right now. For SM1D12SZ the distance between the leaves is 2.35 mm. The distance from the mounting surface on the side with the external threads to the first set of leaves is 3 mm. Inge@thorlabs.com
blecompte  (posted 2008-07-23 12:46:33.0)
Do you have a 3d solid model of the SM1D12SZ yet? Or can you tell me the location of the iris leaves relative to the mounting surface?

SM05-Threaded, Lever-Actuated Iris Diaphragm

SM05D5 Diagram
Click to Enlarge

SM05D5 Mechanical Diagram
  • SM05 (0.535"-40) Threaded on Both Sides
  • Lever-Controlled, Ø0.7 mm - Ø5 mm Aperture
  • Black Spring Steel Leaves

The SM05D5 lever-actuated iris diaphragm is SM05-threaded for compatibility with our Ø1/2" lens tubes and other SM05-threaded accessories. The housing features an engraved arrow which indicates the direction the lever must be moved to close the aperture. One side of the iris is externally threaded, while the other is internally threaded. This allows for easy insertion into existing systems using standard lens tube components.

The setscrews on the housing retain the internal aperture mechanism within the housing and should not be adjusted.

Based on your currency / country selection, your order will ship from Newton, New Jersey  
+1 Qty Docs Part Number - Universal Price Available
SM05D5 Support Documentation
SM05D5SM05 Lever-Actuated Iris Diaphragm (Ø0.7 - Ø5 mm)
$80.07
Today

SM1-Threaded, Lever-Actuated Iris Diaphragms

  • SM1 (1.035"-40) Threaded on Both Sides
  • Lever-Controlled, Max Aperture up to Ø25 mm
  • Black Spring Steel and Stainless Steel Leaf Versions Available
  • Zero-Aperture Version Available

These lever-actuated iris diaphragms are SM1-threaded for compatibility with our Ø1" lens tubes and other SM1-threaded accessories. The housing of each iris features an engraved arrow which indicates the direction the lever must be moved to close the aperture.

Our SM1D12 and SM1D25 iris diaphragms offer maximum apertures up to Ø12 mm and Ø25 mm, respectively. The SM1D12 iris has internal SM1 threading on one side and external SM1 threading on the other side (see drawing to the right). Our SM1D25 iris has internal SM1 (1.035"-40) threading on both sides of the housing (see drawing to the right) as well as a full Ø25 mm aperture.

The SM1D12SS iris features stainless steel leaves for use in higher power applications than traditional spring steel irises. The aperture can be continuously varied from the maximum aperture diameter of 11.9 mm to a minimum aperture diameter of 1.0 mm. The lever-activated diaphragm is designed to provide smooth operation for several thousand cycles. An engraved arrow indicates the position the lever must be in to close the iris. We use a magnetic stainless steel in this iris. Due to its hardness, it offers a longer lifetime than typical non-magnetic stainless steel. This iris also has internal SM1 (1.035"-40) threading on one side and external SM1 threading on the other.

The SM1D12SZ zero-aperture iris diaphragm is continuously variable from the maximum aperture diameter of 11.9 mm to completely closed (zero aperture). Our zero-aperture design achieves a completely closed aperture by utilizing two sets of steel leaves mounted in two adjacent planes. The iris leaves are made from black spring steel and the lever-activated diaphragm is designed to provide smooth operation for several thousand cycles. These irises feature an engraved arrow on the housing which indicates the direction the lever must be moved to close the aperture. As the aperture gets smaller, it also becomes slightly elliptical due to the design of the iris. This housing has internal SM1 (1.035"-40) threading on one side and external SM1 threading on the other.

The setscrews on the housings of these irises retain the internal aperture mechanism within the housing and should not be adjusted.

SM1D12 Diagram
Click to Enlarge

SM1D12 Mechanical Diagram
SM1D25 Diagram
Click to Enlarge

SM1D25 Mechanical Diagram
SM1D12SS Diagram
Click to Enlarge

SM1D12SS Mechanical Diagram
SM1D12SZ Diagram
Click to Enlarge

SM1D12SZ Mechanical Diagram
Based on your currency / country selection, your order will ship from Newton, New Jersey  
+1 Qty Docs Part Number - Universal Price Available
SM1D12 Support Documentation
SM1D12SM1 Lever-Actuated Iris Diaphragm (Ø0.8 - Ø12 mm)
$63.22
Today
SM1D25 Support Documentation
SM1D25Customer Inspired! SM1 Lever-Actuated Iris Diaphragm (Ø1 - Ø25 mm)
$98.16
Today
SM1D12SS Support Documentation
SM1D12SSSM1 Lever-Actuated Stainless Steel Iris Diaphragm (Ø1 - Ø11.9 mm)
$78.20
Today
SM1D12SZ Support Documentation
SM1D12SZSM1 Lever-Actuated Zero Aperture Iris Diaphragm, Ø11.9 mm Max Aperture
$80.70
Today

SM2-Threaded, Lever-Actuated Iris Diaphragm

SM2D25 Diagram
Click to Enlarge

SM2D25 Mechanical Diagram
  • SM2 (2.035"-40) Threaded on Both Sides
  • Lever-Controlled, Ø1 mm - Ø25 mm Aperture
  • Black Spring Steel Leaves

The SM2D25 lever-actuated iris diaphragm is SM2-threaded for compatibility with our Ø2" lens tubes and other SM2-threaded accessories. The housing features an engraved arrow which indicates the direction the lever must be moved to close the aperture. One side of the iris is externally threaded, while the other is internally threaded. This allows for easy insertion into existing systems using standard lens tube components.

The setscrews on the housing retain the internal aperture mechanism within the housing and should not be adjusted.

Based on your currency / country selection, your order will ship from Newton, New Jersey  
+1 Qty Docs Part Number - Universal Price Available
SM2D25 Support Documentation
SM2D25SM2 Lever-Actuated Iris Diaphragm (Ø1 - Ø25 mm)
$102.88
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SM3-Threaded, Lever-Actuated Iris Diaphragm

SM3D50 Diagram
Click to Enlarge

SM3D50 Mechanical Diagram
  • SM3 (3.035"-40) Threaded on Both Sides
  • Lever-Controlled, Ø2 mm - Ø50 mm Aperture
  • Black Spring Steel Leaves

The SM3D50 lever-actuated iris diaphragm is SM05-threaded for compatibility with our Ø3" lens tubes and other SM3-threaded accessories. The housing features an engraved arrow which indicates the direction the lever must be moved to close the aperture. One side of the iris is externally threaded, while the other is internally threaded. This allows for easy insertion into existing systems using standard lens tube components.

The setscrews on the housing retain the internal aperture mechanism within the housing and should not be adjusted.

Based on your currency / country selection, your order will ship from Newton, New Jersey  
+1 Qty Docs Part Number - Universal Price Available
SM3D50 Support Documentation
SM3D50SM3 Lever-Actuated Iris Diaphragm (Ø2 - Ø50 mm)
$199.65
Today