End Caps and Plugs


  • End Caps with SM05, SM1, SM2, SM3, C-Mount, or RMS Threading
  • Plugs with SM05, SM1, or SM2 Threading
  • Snap-On Plastic End Cap for Ø1" and Ø2" Lens Tubes
  • Cover for D1N Dovetails

SM1CP2M

Externally SM1-Threaded
End Cap

SM1EC2B

Snap-On Cap for
Ø1" Lens Tubes

CMCP1

Internally C-Mount-Threaded End Cap

SM2PL

Externally
SM2-Threaded Plug

SM05CP2

Externally SM05-Threaded End Cap

RMSCP1

Internally RMS-Threaded
End Cap

D1NEC2

D1N Dovetail Cover

Related Items


Please Wait
Lens Tube Cap, End Cap
Click to Enlarge

SM1EC2B Lens Tube Cap Seals Off the End of a Ø1" Lens Tube

Thorlabs offers a selection of anodized aluminum SM-threaded end caps and plugs for use with Ø1/2", Ø1", Ø2", and Ø3" lens tubes. We also offer plastic snap-on caps for Ø1" and Ø2" lens tubes, as well as a plastic cover for D1N dovetails. Additionally, there are anodized aluminum caps for use with C-mount and RMS threaded components available. 

The end caps are useful for sealing off the end of imaging components for protecting the optics during transport or storage. The plugs can be threaded deep into a lens tube to produce a seal closer to the optic and feature two dimples that accept our spanner wrenches. The D1N cover protects against unwanted light and dust. Additionally, a selection of these caps and plugs are marked at their center with a dimple to facilitate custom-sized bores centered on the optical axis of the lens tube, making them useful for machining custom inserts.

Selection Guide
SM05
Threaded
RMS
Threaded
C-Mount
Threaded
SM1
Threaded
Ø1"
Snap-On
SM2
Threaded
Ø2"
Snap-On
D1N 
Dovetail
SM3
Threaded

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 LensesCCD/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"

Posted Comments:
Andrey Kuznetsov  (posted 2019-07-13 16:39:39.45)
SM1CP1 PDF states the thread is 4.0mm deep, based on other dimensions and solidworks file, the thread depth is 2.0mm and cavity depth is 3.6mm. Please update the PDF.
llamb  (posted 2019-07-16 01:38:23.0)
Thank you for bringing this to our attention. We will correct the PDF drawing.
akuznetsov  (posted 2018-10-25 23:07:47.41)
For 2" end caps, there is an LCP01 cage plate that you can mount the end cap into and then place the cage mount into a vise on a mill and make holes in the end cap without damaging the threads, etc. But I cannot find a suitable equivalent to do the same thing with the 3" lens cap. If I try to hold the lens cap by the sides, I will damage the threads. I could try using double stick tape to hold the part down but I'm afraid that the milling force might be too big and rip the part off the tape.
llamb  (posted 2018-10-26 09:28:54.0)
Thank you for your feedback. While we do not have a larger cage plate with SM3 thread to ideally mimic your setup, you may consider using another SM3-threaded product to work with, such as our SM3A95 adapter (which has 60 mm cage compatibility) or our LMR3 lens mount.
cbrideau  (posted 2017-10-30 16:41:41.333)
I found these useful for capping ports on equipment that had to be shipped. They were easy to put on and take off and stayed secure in transit.
tfrisch  (posted 2017-11-15 01:26:52.0)
Hello, thank you for the feedback. I'm glad these were able to protect your optical surfaces in transit!
gdovillaire  (posted 2016-08-31 14:11:25.697)
Hi, Do you manufacture these caps without any mark on the front ? Thanks, Guillaume
bjorn.lenormand  (posted 2015-12-03 13:50:46.967)
A step file for the SM1PL is missing, could you please provide this as well?
besembeson  (posted 2015-12-03 10:37:45.0)
Response from Bweh at Thorlabs USA: Thanks for bringing this to our attention. I will share this with you and we will add to the web.
cdaly  (posted 2012-11-30 22:19:47.32)
Response from Chris at Thorlabs: Thank you for using our feedback feature. These lens tube caps/plugs are all made from black anodized aluminum.
farrell  (posted 2012-11-29 10:56:24.843)
Are these end caps machined from metal or are they made of plastic?
Thorlabs  (posted 2010-09-14 15:35:26.0)
Response from Javier at Thorlabs to last poster: Thank you very much for your feedback. I will bring this to the attention of our design engineers and we will possibly add it to our list of upcoming products.
user  (posted 2010-09-14 13:52:14.0)
I would like to see plastic end cap covers that would slip over the 1" lens tubes to protect optics from dust when not in use.
klee  (posted 2009-11-13 18:19:52.0)
A response from Ken at Thorlabs to d.sproles: We did have some internal discussions about this but there is no definite plan to bring a SM05 plug to the market yet. In the meantime, we can make this as a special. If you are interested, please let us know the quantity and we can send you a quotation.
d.sproles  (posted 2009-11-13 12:57:42.0)
Still no SM05 plug? :(
ghegenbart  (posted 2008-11-28 08:56:06.0)
Response from Gerald (Tech Support Thorlabs GmbH Germany) to M. Zimmermann: Thank you very much for your product idea. We already got several requests about a SM05 plug similar to the SM1PL and are planning on adding this product to our offering.
m.zimmmermann  (posted 2008-11-28 06:07:02.0)
SM1PL - SM1 Plug: It would be useful to have such a plug for SM 0.5. Best regards.

Ø1/2" Lens Tube End Caps and Plugs

  • SM05CP1: Internally SM05-Threaded End Cap
  • SM05CP2: Externally SM05-Threaded End Cap
  • SM05PL: Externally SM05-Threaded Plug
  • SM05A7: Externally SM05-Threaded Alignment Target

The SM05CP1 and SM05CP2 are black-anodized aluminum end caps used to seal off a Ø1/2" lens tube. The SM05CP1 has internal SM05 (0.535"-40) threads to seal the end of an externally SM05-threaded lens tube, while the SM05CP2 has external SM05 threads to seal the end of an internally SM05-threaded lens tube. Both caps have a knurled edge to allow them to be securely hand tightened.

The SM05PL lens tube plug has external SM05 (0.535"-40) threads along its entire length and is designed to seal off our Ø1/2" lens tubes. It can be threaded into an SM05 lens tube using an SPW801 spanner wrench that can be adjusted so that the tips of the prongs on the SPW801 fit into the two shallow holes, each of which is located 0.20" from the center dimple. The center dimple of the SM05PL allows it to be customized in a machine shop with excellent centration.

The SM05A7 alignment disk provides useful aids for aligning visible beams to the center of optical mounts. To enable accurate alignment, the disk has clear markings with graduations on both the X and Y axes. The back of the alingment disk features our standard SM05 (0.535"-40) threading for compatibility with Ø1/2" lens tubes and fixed optic mounts.
 
 

Based on your currency / country selection, your order will ship from Newton, New Jersey  
+1 Qty Docs Part Number - Universal Price Available
SM05CP1 Support Documentation
SM05CP1Internally SM05-Threaded End Cap
$16.66
Today
SM05CP2 Support Documentation
SM05CP2Externally SM05-Threaded End Cap
$16.66
Today
SM05PL Support Documentation
SM05PLExternally SM05-Threaded Plug
$14.33
Today
SM05A7 Support Documentation
SM05A7SM05 Series Alignment Disk
$20.45
3 weeks

RMS Caps

Objective Lens Turret Protected by RMSCP2 Dust Cap
Click to Enlarge

RMSCP2 Protecting Turret Ports
Microscope Objective Covered by RMSCP1 Dust Cap
Click to Enlarge

RMSCP1 Covering an Objective
  • RMSCP1: Internally RMS-Threaded Cap
  • RMSCP2: Externally RMS-Threaded Cap

These RMS-Threaded Caps are designed to protect microscope objectives lenses, objective lens ports, and other RMS (0.800"-36) threaded components. The RMSCP1 features internal RMS threading, which enables them to be used with standard RMS-threaded microscope objectives. The RMSCP2 features external RMS threading to cover unused objective lens ports (see image on the far right). Each of these caps is made from anodized aluminum and has a knurled edge for secure hand tightening.

Based on your currency / country selection, your order will ship from Newton, New Jersey  
+1 Qty Docs Part Number - Universal Price Available
RMSCP1 Support Documentation
RMSCP1Internally RMS-Threaded Cap for Microscope Objective Lenses
$18.52
Today
RMSCP2 Support Documentation
RMSCP2Externally RMS-Threaded Cap for Objective Lens Ports
$18.52
Today

C-Mount Caps

Lens Tube Cap, End Cap
Click to Enlarge
Each Cap is Engraved with
Part Number
  • CMCP1: Internally C-Mount-Threaded Cap
  • CMCP2: Externally C-Mount-Threaded Cap

These C-Mount Caps are designed to be used with our CCD/CMOS camerasC-mount extension tubes, camera lenses, and other C-mount-threaded (1.00" -32) components. The CMCP1 features internal C-mount threading while the CMCP2 features external C-mount threading. Each of these caps is made from black-anodized aluminum and has a knurled edge for secure hand tightening.

To use one of these caps with a C-mount-threaded CCD or CMOS camera, please choose the externally threaded CMCP2 cap.

Based on your currency / country selection, your order will ship from Newton, New Jersey  
+1 Qty Docs Part Number - Universal Price Available
CMCP1 Support Documentation
CMCP1Customer Inspired! Internally C-Mount-Threaded Cap
$20.27
Today
CMCP2 Support Documentation
CMCP2Customer Inspired! Externally C-Mount-Threaded Cap
$20.27
Lead Time

Ø1" Lens Tube End Caps and Plugs

  • SM1CP1: Internally SM1-Threaded End Cap
  • SM1CP2: Externally SM1-Threaded End Cap
  • SM1CP2M: Externally SM1-Threaded End Cap for Machining
  • SM1PL: Externally SM1-Threaded Plug
  • SM1A7: Externally SM1-Threaded Alignment Disk

The SM1CP1 and SM1CP2 are black-anodized aluminum end caps used to seal off a Ø1" lens tube. The SM1CP1 has internal SM1 (1.035"-40) threads to seal the end of an externally SM1-threaded lens tube, while the SM1CP2 has external SM1 threads to seal the end of an internally SM1-threaded lens tube. Both caps have a knurled edge to allow them to be securely hand tightened. The SM1CP2 features engraved crosshairs on one side that can be used for quick coarse alignment. For applications that require more precise alignment, please see our full selection of alignment tools.

The SM1CP2M is an end cap with external SM1 threading and a knurled lip, while the SM1PL is a plug (no lip) with external SM1 threading. The SM1PL plug can be threaded into an SM1 lens tube using an SPW801 or SPW909 spanner wrench, both of which will fit into the two shallow holes located 10 mm from the center. The SM1CP2M and SM1PL both have a center drilled dimple located on the optical axis to allow them to be customized in a machine shop with excellent centration.

The SM1A7 alignment disk provides useful aids for aligning visible beams to the center of optical mounts. To enable accurate alignment, the disk has clear markings with graduations on both the X and Y axes. The back of the SM1A7 has SM1 (1.035"-40) threading for compatibility with Ø1" lens tubes and fixed optic mounts
 

Based on your currency / country selection, your order will ship from Newton, New Jersey  
+1 Qty Docs Part Number - Universal Price Available
SM1CP1 Support Documentation
SM1CP1Internally SM1-Threaded End Cap
$20.27
Today
SM1CP2 Support Documentation
SM1CP2Externally SM1-Threaded End Cap
$20.27
Today
SM1CP2M Support Documentation
SM1CP2MExternally SM1-Threaded End Cap for Machining
$20.59
Today
SM1PL Support Documentation
SM1PLExternally SM1-Threaded Plug
$16.66
Today
SM1A7 Support Documentation
SM1A7SM1 Series Alignment Disk
$20.45
Lead Time

Ø1" Snap-On Lens Tube Dust Cap

Lens Tube Cap, End Cap
Click to Enlarge
Back View of SM1EC2B Snap-On End Cap
  • SM1EC2B: Plastic Snap-On Dust Caps for Ø1" Lens Tubes
  • Ideal for Temporary Protection of Components
  • Sold in Packs of Five

    The SM1EC2B plastic dust cap snaps onto internally SM1-threaded (1.035"-40) components, such as 30 mm cage plates and cubes or the internally threaded end of a Ø1" lens tube (see photo in the Overview tab). By sealing off the end of a lens tube or cage cube, this cap helps to protect optics against dust and debris while not in active use. The SM1EC2B cap has an outer diameter of 1.20" (30.5 mm). It is not compatible with C-mount threads.

    The lens cap is placed on the lens tube by squeezing the protruding edge of the cap, inserting the back of the cap into the lens tube, and then releasing the cap. To avoid deforming the cap, be sure to squeeze the protruding edge when removing it. Avoid using these caps in high heat environments as the cap can deform; use at temperatures between 0 °C to 40 °C for best results.

    Based on your currency / country selection, your order will ship from Newton, New Jersey  
    +1 Qty Docs Part Number - Universal Price Available
    SM1EC2B Support Documentation
    SM1EC2BSnap-On Plastic Dust Cap for SM1 Lens Tubes, 5 Pack
    $11.66
    Today

    Ø2" Lens Tube End Caps and Plugs

    • SM2CP1: Internally SM2-Threaded End Cap
    • SM2CP2: Externally SM2-Threaded End Cap
    • SM2PL: Externally SM2-Threaded Plug

    The SM2CP1 and SM2CP2 are black-anodized aluminum end caps that allow a Ø2" lens tube to be sealed off. The SM2CP1 has internal SM2 (2.035"-40) threads to seal the end of an externally SM2-threaded lens tube, while the SM2CP2 has external SM2 threads to seal the end of an internally SM2-threaded lens tube. Both caps have a knurled edge to allow them to be securely hand tightened.

    The SM2PL is a blank plug with external SM2 threading. It can be threaded into a lens tube using an SPW801 spanner wrench that can be adjusted so that the tips of the prongs on the SPW801 fit into the two shallow holes machined near the edge of the plug. The center of the SM2PL plug is dimpled to allow it to be customized in a machine shop with excellent centration.

    Based on your currency / country selection, your order will ship from Newton, New Jersey  
    +1 Qty Docs Part Number - Universal Price Available
    SM2CP1 Support Documentation
    SM2CP1Internally SM2-Threaded End Cap
    $21.43
    Today
    SM2CP2 Support Documentation
    SM2CP2Externally SM2-Threaded End Cap
    $21.43
    Today
    SM2PL Support Documentation
    SM2PLExternally SM2-Threaded Plug
    $17.82
    Today

    Ø2" Snap-On Lens Tube Dust Cap

    Lens Tube Cap, End Cap
    Click to Enlarge
    Back View of SM2EC2 Snap-On End Cap
    • SM2EC2: Plastic Snap-On Dust Caps for Ø2" Lens Tubes
    • Ideal for Temporary Protection of Components
    • Sold in Packs of Five

      The SM2EC2 plastic dust cap snaps onto internally SM2-threaded (2.035"-40) components, such as 60 mm cage plates and cubes or the internally threaded end of a Ø2" lens tube. By sealing off the end of a lens tube or cage cube, this cap helps to protect optics against dust and debris while not in active use. The SM2EC2 cap has an outer diameter of 2.20" (55.8 mm).

      The lens cap is placed on the lens tube by squeezing the protruding edges of the cap, inserting the back of the cap into the lens tube, and then releasing the cap. To avoid deforming the cap, be sure to squeeze the protruding edge when removing it. Avoid using these caps in high heat environments as the cap can deform; use at temperatures between 0 °C to 40 °C for best results.

      Based on your currency / country selection, your order will ship from Newton, New Jersey  
      +1 Qty Docs Part Number - Universal Price Available
      SM2EC2 Support Documentation
      SM2EC2Snap-On Plastic Dust Cap for SM2 Lens Tubes, 5 Pack
      $22.84
      Today

      D1N Dovetail Cover

      Lens Tube Cap, End Cap
      Click to Enlarge
      Back View of D1NEC2 D1N Dovetail Cover
      D1N Cover on Nikon Microscope
      Click to Enlarge
      The D1N Dovetail Cover on the CSD1002 Double Camera Port
      • D1NEC2: Plastic Cover for D1N Female Dovetails
      • Ideal for Blocking Light and Protecting Components from Dust
      • Features a Finger Grip for Easy Handling

        The D1NEC2 plastic cover is ideal for covering unused ports in order to prevent unwanted light and dust from damaging or disrupting an imaging system. It is compatible with any component that has a D1N female dovetail, such as our epi-illuminator modulessingle-channel confocal systems, and double camera ports. It can also be used to cover the trinocular port on a Nikon Eclipse Upright or Ti Microscope (click the links to view a diagram of each system with labeled ports). The cap has an outer diameter of 2.85" (72.4 mm), is made from ABS plastic, and features a finger grip on the top for easy handling.

        Based on your currency / country selection, your order will ship from Newton, New Jersey  
        +1 Qty Docs Part Number - Universal Price Available
        D1NEC2 Support Documentation
        D1NEC2D1N Dovetail Cover
        $33.12
        Today

        Ø3" Lens Tube End Cap


        Click to Enlarge

        Each SM3 end cap is engraved with its part number and a centered crosshairs for alignment.
        • SM3CP1: Internally SM3-Threaded End Cap
        • SM3CP2: Externally SM3-Threaded End Cap

        The SM3CP1 and SM3CP2 are black-anodized aluminum end caps that allow SM3-threaded (3.035"-40) lens tubes to be sealed off. The SM3CP1 has internal SM3 (3.035"-40) threads to seal the end of an externally SM3-threaded lens tube, while the SM3CP2 has external SM3 threads to seal the end of an internally SM3-threaded lens tube.

        Both caps have a knurled edge which allows them to be securely hand tightened. Each cap also features engraved crosshairs on one side that can be used for quick coarse alignment, as shown in the image to the right. For applications that require more precise alignment, please see our full selection of alignment tools

        Based on your currency / country selection, your order will ship from Newton, New Jersey  
        +1 Qty Docs Part Number - Universal Price Available
        SM3CP1 Support Documentation
        SM3CP1Customer Inspired! Internally SM3-Threaded End Cap
        $34.66
        Today
        SM3CP2 Support Documentation
        SM3CP2Externally SM3-Threaded End Cap
        $34.66
        Today
        Last Edited: Aug 02, 2013 Author: Lori Stover