End Caps and Plugs

End Caps with SM05, SM1, SM2, SM3, RMS, M25 x 0.75, or C-Mount Threading
Plugs with SM05, SM1, or SM2 Threading
Snap-On Plastic End Caps for C-Mount, SM1-, or SM2-Threaded 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

SM05EC2

Soft Dust Cap for SM05 Lens Tubes

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Overview
Threading Specs
Feedback

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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. Additionally, there are anodized aluminum caps for use with RMS, M25 x 0.75, and C-mount-threaded components available. We also offer plastic snap-on caps for C-mount, Ø1", and Ø2" lens tubes, as well as a plastic cover for D1N dovetails.

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	M25 x 0.75 Threaded	C-Mount Threaded	C-Mount Snap-On	SM1 Threaded	Ø1" Snap-On	SM2 Threaded	Ø2" Snap-On	D1N Dovetail	SM3 Threaded

Click to Enlarge

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 Grades^a
Minor Diameter	Internal	4, 5, 6, 7, 8
Major Diameter	External	4, 6, 8
Pitch Diameter	Internal	4, 5, 6, 7, 8
Pitch Diameter	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:

Paul Clark (posted 2024-09-09 14:14:37.923)

It would help if you gave a description of what the cap is for? What does it fit? I am looking for a cap to plug one end of a 2" pipe union, but there is no way to know if it fits a union, or anything else!

jpolaris (posted 2024-09-10 03:38:56.0)

Thank you for contacting Thorlabs. If you are on a product-specific page, clicking "Complete Product Details" below the product image will take you a page with complete descriptions of each part in the product line. SM2CP2 is an end cap for Ø2" lens tubes, which are internally SM2 threaded. You can find threading specs for SM-series thread types at the following link. https://www.thorlabs.com/newgrouppage9.cfm?objectgroup_id=3519&tabname=Threading_Specs

Andrey Kuznetsov (posted 2024-05-18 03:15:50.94)

Please update SM1CP1 CAD files to use solid body models instead of hollow sheets, cannot design with hollow models!

jpolaris (posted 2024-06-17 04:42:19.0)

Thank you for contacting Thorlabs. We have updated the .STEP file for SM1CP1 as you have requested.

Nathan Bramall (posted 2022-08-03 11:54:47.92)

Hi, The solid models for SM05PL (both SolidWorks and STEP) were exported using only surfaces. This makes it impossible for SolidWorks to work with-- can't modify this part to incorporate into optical designs. I don't remember this being the case in the past... Best, Nathan

cdolbashian (posted 2022-08-16 09:41:16.0)

Thank you for finding this Nathan! We have updated the part so that it is a solid body, rather than an assembly of surfaces.

Paul Carpenter (posted 2022-07-26 14:10:25.01)

The SM05PL (Externally SM05 Threaded Plugs) that arrived do not have spanner wrench holes on both sides as shown in the drawing and solid model. The spanner wrench holes are only on the side with the drill point center mark & company/part # markings.

jdelia (posted 2022-07-29 02:17:33.0)

Thank you for contacting Thorlabs. The parts are only meant to come with the holes on one side. We are currently looking into updating the website to better reflect this. In the meantime, I have reached out to you regarding options on how to proceed with the parts you currently have.

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

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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 alignment disk features our standard SM05 (0.535"-40) threading for compatibility with Ø1/2" lens tubes and fixed optic mounts.

Ø1/2" Lens Tube Soft Dust Cap

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Click to Enlarge
Back View of the SM05EC2 Soft Dust Cap

SM05EC2: Externally SM05-Threaded Plastic Soft Dust Caps for Ø1/2" Lens Tubes
Ideal for Temporary Protection of Components
Sold in Packs of Five

The SM05EC2 Soft Dust Cap has external SM05 (0.535"-40) threads and can be used to seal off our Ø1/2" lens tubes. This cap helps to protect optics against dust and debris while not in active use. The SM05EC2 cap is 24.6 mm (0.97") across its widest point where two fins extend from the Ø17.8 mm (Ø0.70") central part of the cap.

To remove the cap, either unscrew it or pinch the cap via the fins on either side and pull off the tube. If the cap is on a flat surface without room to pinch the side fins, pull on the longer fin to remove the cap. 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.

RMS Caps

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Objective Lens Turret Protected by RMSCP2 Dust Cap

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RMSCP2 Protecting Turret Ports

Microscope Objective Covered by RMSCP1 Dust Cap

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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.

M25 x 0.75 Caps

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Each Cap is Engraved with
Part Number and Alignment Marker

M25CP1: Internally M25 x 0.75-Threaded Cap
M25CP2: Externally M25 x 0.75-Threaded Cap

These M25 x 0.75-Threaded Caps are designed to protect microscope objectives, objective lens ports, and other M25 x 0.75-threaded components. The M25CP1 cap features internal M25 x 0.75 threading, which enables it to be used with a standard M25 x 0.75-threaded microscope objective. The M25CP2 cap features external M25 x 0.75 threading to cover unused objective lens ports. Both M25CP1 and M25CP2 caps feature an alignment engraving to aid in the alignment of visible beams. Each of these caps is made from anodized aluminum and has a knurled edge for secure hand tightening.

C-Mount Caps

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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 cameras, C-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.

C-Mount Snap-On Cap

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Back View of CMEC2 Snap-On End Cap

CMEC2: Plastic Snap-On Dust Caps for C-Mount Cameras and Accessories
Ideal for Temporary Protection of Components
Sold in Packs of Five

The CMEC2 plastic dust cap snaps onto internally C-Mount-threaded (1.00"-32) components, such as our CCD/CMOS cameras and C-mount extension tubes. By sealing off the end of C-Mount camera accessory or lens tube, this cap helps to protect optics against dust and debris while not in active use. The CMEC2 cap has an outer diameter of 30.5 mm (1.2").

The lens cap can be placed on an internally C-mount threaded component by squeezing the protruding edge of the cap, inserting the back of the cap into the threads, 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.

Ø1" Lens Tube End Caps and Plugs

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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.

Ø1" Snap-On Lens Tube Dust Cap

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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.

Ø2" Lens Tube End Caps and Plugs

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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.

Ø2" Snap-On Lens Tube Dust Cap

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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.

D1N Dovetail Cover

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Back View of D1NEC2 D1N Dovetail Cover

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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 modules, four-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.

Ø3" Lens Tube End Cap

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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.