Standard 30 mm Cage Plates

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Cage Overview
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Alternative Size Options
16 mm Cage Plates
30 mm Cage Plates
60 mm Cage Plates

The Cage Assembly System provides a convenient way to construct large optomechanical systems with an established line of precision-machined building blocks designed for high flexibility and quick, accurate alignment. The 30 mm cage plates featured below provide a means for mounting optical components with diameters ranging from 5 mm to 1" within a cage system. Many of the components are post mountable via an 8-32 (M4) tap in the cage plate (see below for details).

Cage System Compatibility: Thorlabs offers 16 mm, 30 mm, and 60 mm cage systems primarily designed for Ø1/2", Ø1", and Ø2" optical components, respectively. The parts on this page are compatible with our 30 mm cage system and utilize Ø6 mm ER cage rods.

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Many of Our Cage Plates Have Internal SM1 Threads

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CP33 Cage Plate shown with HKTS-5/64 Hex Key Thumbscrews for Easy Adjustment

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CP42 Cage Plate Mounting an RMS-Threaded Objective in a 30 mm Cage System

Selection Guide
Item #	Inner Bore	Plate Thickness	Post Mounting	Cage Rod Locking Mechanism^f
CP32(/M)	SM05 Threaded^a	0.35" (8.9 mm)	8-32 (M4)	Setscrew, 5/64" (2.0 mm) Hex
CP33(/M)	SM1 Threaded^a	0.35" (8.9 mm)	8-32 (M4)	Setscrew, 5/64" (2.0 mm) Hex
CP33T(/M)	SM1 Threaded^a	0.50" (12.7 mm)	8-32 (M4)	Setscrew, 5/64" (2.0 mm) Hex
CP02F(/M)	SM1 Threaded^a	0.35" (8.9 mm)	8-32 (M4) 1/4"-20 (M6)	Cap Screw Flexure, 5/64" (2.0 mm) Hex
CP08(/M)	SM1 Threaded^a	0.35" (8.9 mm)	8-32 (M4)	Cap Screw Flexure, 3/32" (2.5 mm) Hex
CP4S	SM1 Threaded^a	0.16" (4.0 mm)	N/A	Setscrew, 0.05" (1.3 mm) Hex
CP6T	SM1 Threaded^a	0.24" (6.0 mm)	N/A	Setscrew, 5/64" (2.0 mm) Hex
CP8T	SM1 Threaded^a	0.31" (8.0 mm)	N/A	Setscrew, 5/64" (2.0 mm) Hex
CP42(/M)	RMS (0.800"-36) Threaded	0.35" (8.9 mm)	8-32 (M4)	Setscrew, 5/64" (2.0 mm) Hex
CP13(/M)	C-Mount (1.00"-32) Threaded	0.35" (8.9 mm)	8-32 (M4)	Setscrew, 5/64" (2.0 mm) Hex
CP14(/M)	Ø1/2" Double Bore with Setscrew	0.35" (8.9 mm)	8-32 (M4)	Setscrew, 5/64" (2.0 mm) Hex
CP35(/M)	Ø1" Double Bore with Setscrew	0.35" (8.9 mm)	8-32 (M4)	Setscrew, 5/64" (2.0 mm) Hex
CP06F(/M)	Ø1" Double Bore with Setscrew	0.35" (8.9 mm)	8-32 (M4)	Cap Screw Flexure, 5/64" (2.0 mm) Hex
CP36	Ø1.2" Double Bore^b with Setscrew	0.35" (8.9 mm)	N/A	Setscrew, 5/64" (2.0 mm) Hex
CP37(/M)	Ø35 mm Double Bore^c with Setscrew	0.35" (8.9 mm)	8-32 (M4)	Setscrew, 5/64" (2.0 mm) Hex
CP38	SM1 Threaded^a	0.35" (8.9 mm)	N/A	Setscrew, 5/64" (2.0 mm) Hex
CP38T	SM1 Threaded^a	0.35" (8.9 mm)	N/A	Setscrew, 5/64" (2.0 mm) Hex
CP1Mxx	M6, M8, M9, M10, or M12 Threaded^d	0.35" (8.9 mm)	8-32 (M4)	Setscrew, 5/64" (2.0 mm) Hex
CPNxx	M5.5, M6.5, M8.5, M9.5, M15.5, 0.750"-40, or M20.5 Threaded^e	0.23" - 0.40" (5.7 mm - 10.2 mm)	N/A	Setscrew, 5/64" (2.0 mm) Hex
CP31(/M)	None	0.35" (8.9 mm)	8-32 (M4)	Setscrew, 5/64" (2.0 mm) Hex
CPG3	Cage Plate Gasket for Light-Tight Applications
ERCPS	Cage Plate Stops for Precise Alignment
CPA1 CPA2 VRC4CPT VRC6SCPT	Alignment Guides for the 30 mm Cage System

In addition to being able to secure components with complementary threads, our SM05 (0.535"-40) and SM1 (1.035"-40) thread standards are designed to hold 1/2" and Ø1" optics, respectively.
This double bore diameter is matched to the outer diameter of our SM1 lens tubes.
This double bore diameter is matched to the outer diameter of our SM30 lens tubes and select free-space isolators.
Thread standard for a premounted aspheric or achromatic lens.
Thread standard for holding an unmounted aspheric, achromatic, or other small-diameter (≤Ø20 mm) optic.
We offer replacement setscrews for the cage plates on this page. The SS4S025 can be used in place of the setscrews which have 4-40 threads and require a 0.05" (1.3 mm) hex, while the SS4MS5C can be used in place of the setscrews which have M4 x 0.7 threads and require a 5/64" (2.0 mm) hex.

Cage System Overview

16 mm, 30 mm, and 60 mm Cage System Standards

Thorlabs offers three standards defined by the center-to-center spacing of the cage assembly rods (see image below). The 16 mm cage, 30 mm cage, and 60 mm cage standards are designed to accomodate Ø1/2", Ø1", and Ø2" optics, respectively. Specialized cage plates that allow smaller optics to be directly inserted into our larger cage systems are also available.

Standard Threads

The flexibility of our Cage Assembly System stems from well-defined mounting and thread standards designed to directly interface with a wide range of specialized products. The three most prevalent thread standards are our SM05 Series (0.535"-40 thread), SM1 Series (1.035"-40 thread), and SM2 Series (2.035"-40 thread), all of which were defined to house the industry's most common optic sizes. Essential building blocks, such as our popular lens tubes, directly interface to these standards.

An example of the standard cage plate measurements determining cage system compatibility.

Standard Cage System Measurements
Cage System	16 mm	30 mm	60 mm
Thread Series	SM05	SM1	SM2
Rod to Rod Spacing	16 mm (0.63")	30 mm (1.18")	60 mm (2.36")
Total Length	25 mm (0.98")	41 mm (1.60")	71.1 mm (2.8")

Cage Components
Cage Rods	16 mm	These rods are used to connect cage plates, optic mounts, and other components in the cage system. The SR Series Cage Rods are compatible with our 16 mm cage systems, while the 30 mm and 60 mm cage systems use ER Series Cage Rods.
	30 mm
	60 mm
Cage Plates	16 mm	These serve as the basic building blocks for a cage system. They may have SM-threaded central bores, smooth bores sized for industry standard optics or to accommodate the outer profile of our SM Series Lens Tubes, or specialized bores for other components such as our FiberPorts.
	30 mm
	60 mm
Optic Mounts	16 mm	Thorlabs offers fixed, kinematic, rotation, and translation mounts specifically designed for our Cage Systems.
	30 mm
	60 mm
Cage Cubes	16 mm	These cubes are useful for housing larger optical components, such as prisms or mirrors, or optics that need to sit at an angle to the beam path, such as beamsplitters. Our cage cubes are available empty or with pre-mounted optics.
	30 mm
	60 mm
Post and Breadboard Mounts and Adapters		Mounting options for cage systems can be found on our Cage System Construction pages. Cage Systems can be mounted either parallel or perpendicular to the table surface.
Size Adapters		Cage System Size Adapters can be used to integrate components from different cage system and threading standards.
Specialized Components		Thorlabs also produces specialized cage components, such as Filter Wheels, a HeNe Laser Mount, and a FiberPort Cage Plate Adapter, allowing a wide range of our products to be integrated into cage-mounted optical systems. Explore our Cage Systems Visual Navigation Guide to see the full range of Thorlabs' cage components.

Posted Comments:

Tom Dzelzainis (posted 2021-02-01 16:11:32.87)

Hi, The description of the CP36 says that it is not post mountable as the threaded hole would interfere with the central bore. How come the CP37 can be made post mountable? This part has the same outer dimensions as the CP36, but has a larger bore. The alternatives for post mounting of an SM1 tube are not cage compatible and therefore not suitable for most cage set-ups. The absence of a post mountable cage plate that can hold an SM1 tube without using the threading is a major problem with this range. Many thanks, Tom.

YLohia (posted 2021-03-18 02:27:46.0)

Hello, thank you for your feedback. The CP37 can be used as a cage support, but the tap is not functional when mounting a 30mm lens tube. The stud length on the TR posts ranges between 0.180" and 0.210". If at the 0.210" long dimension, it would crash into the lens tube and cause damage so the mounting option was not added. This same issue exists on the CP37 when mounting a 30mm lens tube, but this was not the initial intent of product. Our engineering team will look at a way to modify the design of the CP36 to accommodate a mounting hole.

user (posted 2021-01-08 14:23:42.857)

It would be great to have a common SM1 threaded cage plate like CP33/M available with a fine thread adjuster, similar to CP1LM9.

llamb (posted 2021-01-09 10:08:16.0)

Thank you for your feedback. We will consider your suggestion further. For the time being, perhaps our SM1Z or CT1 cage translators could also be of interest to you for your application.

Rowan MacQueen (posted 2020-10-27 16:17:13.35)

Hi, This item (and the metric version of it) isn't showing up on the e.biss system at my institution, Helmholtz-Zentrum Berlin. I'd quite like to buy it otherwise.

YLohia (posted 2020-10-28 09:26:41.0)

Hello, stock items can be purchased by contacting our German Sales Team at sales.de@thorlabs.com or +49 (0) 8131-5956-0.

Fang Xian (posted 2020-10-26 20:15:22.29)

Hi，I want to know the diameter of the hole in the middle of CP32 in millimeters.

YLohia (posted 2020-10-26 11:26:31.0)

The SM05 threaded hole in the middle of the CP32 has a min minor diameter for 0.508", which is 12.9032 mm. The clear aperture is 10.9mm with the retaining ring installed. More specs for this internal thread can be found here: https://www.thorlabs.com/newgrouppage9.cfm?objectgroup_id=1535&tabname=Threading%20Specs

Wance Wang (posted 2020-01-08 12:29:43.213)

Hi, I am building parallel 30mm cages (2 30mm cages sharing 2 common rods). I wonder if you have 30mm plate which has 6 holes for this parallel cages? Of course one can build it with 2 CP33 plates (for example), but I feel an integrated plate is better. In addition, vertical mount UBP2 also only has 4 holes so it can't mount those parallel cages, and I can't make 2 of them parallel with a 30mm spacing. If there is a vertical plate with 6 30mm hole, it would be great. Thank you!

YLohia (posted 2020-01-08 03:20:22.0)

Hello, thank you for contacting Thorlabs. I have reached out to you directly to discuss the possibility of offering this.

John Bragg (posted 2019-12-16 11:31:12.52)

I need the RoHS Compliance Certificate for CP33. It is not downloadable from the website. Thank you, John Bragg jbragg@cytonome.com

YLohia (posted 2019-12-16 04:19:07.0)

Thank you for contacting Thorlabs. I have reached out to you with this information.

Bolin Liao (posted 2019-07-29 21:35:23.807)

Hi, I'm wondering what kind of anodization was used for the surface finish of the cage plates? Is it high-vacuum (1e-6 torr level) compatible? If not, could you custom-fabricate the cage plates with stainless steel? Thanks! Best, Bolin

YLohia (posted 2019-07-30 11:52:55.0)

Hello Bolin, thank you for contacting Thorlabs. The cage plates are 6061-T6 aluminum anodized and are not rated for high-vacuum use. For custom item quotes, please email techsupport@thorlabs.com.

user (posted 2019-04-02 11:21:49.95)

Hello, I imported the step file for this item into Autocad and am trying now to export it as a different file type. Autocad says that this model is not "water tight." The CP02T worked fine. Do you have a model that is water tight? Best, Jon

llamb (posted 2019-04-11 09:58:45.0)

Hi Jon, thank you for your feedback. I have reached out to you directly to troubleshoot, and we will look into updating the web files accordingly.

Cedric Hurth (posted 2019-04-02 04:47:02.66)

I would like to submit a customer-inspired design for a modified CP4S, how do I proceed? Thank you!

llamb (posted 2019-04-03 09:42:46.0)

Thank you for your interest! For any product suggestions or improvements, you can email techsupport@thorlabs.com. We are always happy to receive product feedback and new product ideas. I have reached out to you by email in this case to discuss your design further.

pszwaykowski (posted 2017-08-17 14:26:40.89)

What are the chances to get a CP01 with clamping features like CP08? I need to modify CP01 plate to accommodate our own creations but can not use the set screws to lock the plate in place. Tightening these screws causes small translation of the plate that can not be easily controlled.

tfrisch (posted 2017-08-28 11:08:53.0)

Hello, thank you for contacting Thorlabs. I will reach out to you directly about details to quote this custom plate.

ludoangot (posted 2017-04-10 10:40:26.51)

I have a suggestion for new cage plate: one plate able to receive rods from either (or both) of your 30mm and 60mm cage system (e.g. as the CP06 for 30mm, LCP01 for 60mm, LCP02 for both) and offering threaded mounting holes (as several of your surface mounting plate, ex. as the detachable mounting plate of your C1001). This would allow to mount, for example, an industrial or scientific camera at the end or in the middle of a cage. The plate would look like your LCP03 (case of your 60mm cage) but thinner and with many threaded (and unthreaded) holes.

tfrisch (posted 2017-04-27 02:19:41.0)

Hello, thank you for contacting Thorlabs. I will reach out to you directly about your application. It would be helpful if you could send a sketch that we could use in our discussion.

ludoangot (posted 2016-09-30 15:05:23.23)

I have several of your cage plates, but today I am looking for one with a 30mm inner bore, and you don't seem to offer any. Could you consider making such dimension, or, as an alternative, offer a mounting adapter (sleeve) so a 30mm diameter element (many 3rd party lenses are 30mm in diameter) could fit in one of your cage plate (e.g. the one with 1.2" bore)?

jlow (posted 2016-10-03 01:39:35.0)

Response from Jeremy at Thorlabs: Yes we can make this. I will contact you directly about quoting this.

eddy.porter (posted 2015-04-21 08:32:23.963)

What is the material and finish of CP01/M Cage Plate? We intend to machine and re-finish the part. Thanks Eddy Porter

jlow (posted 2015-04-22 04:08:23.0)

Response from Jeremy at Thorlabs: The cage plate is made from 6061 aluminum that is anodized with a Type 2 anodization.

gir (posted 2013-05-14 21:54:02.91)

FYI: the #8-32 threaded hole on the CP06 is shown in the AutoCAD PDF file, but not in the SolidWorks model.

tcohen (posted 2013-05-15 12:45:00.0)

Response from Tim at Thorlabs: Thank you for pointing this out! We will fix this shortly.

david.baddeley (posted 2013-05-14 13:17:16.063)

Would you consider offering cage plates with 4-40 threaded holes (to accommodate screws on the ends of cage rods) the drilled and tapped on the sides to allow a second cage system to be attached at right angles. I've previously had this done on existing plates in a local machine shop, and have found it to be a very efficient way of making 3D cage structures. I now have less access to machining facilities, and though it might be worth suggesting as a product variation. Ideally this would also involve a slight increase (~ 1-2 mm in the width of the plate) as the length of the rod threads is such that they will often engage the rod running through the plate before the end of the rod at right angles is flush with the cage plate surface. Cage cubes and right angle rods (ER90C) don't work for my application as the position of the right angle needs to be adjustable. Cross couplers (C1A) won't work as they are too large (I'm putting a KC45D gimbal mirror at the intersection of the two cage systems to deflect the beam from one to the other and it won't fit with the C1As there). many thanks, David

cdaly (posted 2013-05-16 15:37:00.0)

Response from Chris at Thorlabs: Thank you for your suggestion. I will suggest this within our internal discussions. As a quick solution though, would it be possible for you to use C1A, C2A, or ER90C to achieve this as well?

cdaly (posted 2013-03-06 17:59:00.0)

Response from Chris at Thorlabs: We haven't specifically tested the gasket in vacuum, but I was able to find another resource that tested the material. The CPG3 is made of Buna-N, which at an exposure to 10^-6 Torr for 336 hours, experienced a weight loss ratio was 1.06, which is a pretty large value as far as outgassing is concerned. At the moment, we do not make a delrin version. These are intended for light tight purposes in a non-vacuum environment. For general purposes the compressiblity of the material is ideal as it allows it to conform to the objects it is between.

jlow (posted 2012-08-09 09:33:00.0)

Response from Jeremy at Thorlabs: Thank you for your feedback. The CPG3 is designed with a large aperture in mind. It is unfortunate that it does not work with the CP08 because of the slits of the side. I have submitted this feedback to our engineering group and we will look into improving this.

matthias.sauer (posted 2012-08-07 13:48:39.0)

The gasket is not covering the slits of a CP08 cage plate. To fulfill its intended use, it would be helpful if it optically sealed one side of the cage plate from the other.

tcohen (posted 2012-05-01 12:23:00.0)

Response from Tim at Thorlabs: Both the cage system and traditional posts have their uses. The cage system provides an easy way to quickly align along a common optical axis. Posts and post holders allow the flexibility to quickly drop in and adjust the height of a component. Different setups may benefit from one over the other but they are also subject to personal preference. If there is ever a question of which would be preferred, please contact us at techsupport@thorlabs.com where an Applications Engineer will be able to discuss your application and the suitability of the products to fit into your ideal setup.

Carlos.Gulien (posted 2012-04-26 22:33:16.0)

Yes, can you provide your professional opinion on using a cage system vs. using standard posts, post holders, pedestals and so on...can you comment on when I should use each system and what are the pros and cons of each, like ease of use vs. stability vs cost vs anything else you have experienced as a scientist. What system are most people using these days? I tend to trust the "herd" if you know what I mean.

apalmentieri (posted 2010-02-08 08:55:52.0)

A response from Adam at Thorlabs to Dan: Thank you for your feedback. This does count as customer inspired and I have informed our mechanics division of your feedback. I agree that this would make a good addition to the product line. If it is added, we would offer you a prototype to test out the new design. In the meantime, we can offer this item as a custom.

flickingerd (posted 2010-02-04 18:19:11.0)

I wish you had a product like CP06, but for a 2in optic in the 60mm cage system. I can use the FMP2 for my design, but it seems like it will be relatively very wobbly since it doesnt look beefy enough. Does this count as "customer inspiration"?

Laurie (posted 2008-08-07 09:25:07.0)

Response from Laurie at Thorlabs to xavier.schwab: The new metric indicator (i.e., the dot) is a very recent addition to our metric mounts. Unfortunately, this new information must have been added to our website prior to stock depletion of the ones without a metric indicator. There is no difference in the physical functionality of the product. We are merely trying to make it easier/quicker for our customers to look at our parts and know whether they are imperial or metric. That being said, if you would like to return your CP02/M and receive one with a metric indicator, please feel free to speak to our RMA department. We apologize for any confusion or inconvenience we may have caused.

xavier.schwab (posted 2008-08-07 07:17:31.0)

Dear Mr., dear Madam, I will purchase new cage system products. I have a question about the dot near a thread which may signified "Metric". In our actual CP02, we have no dot near the thread but it is a Metric thread. As we would like to keep the same standard, could tell me if its normal? Best regards, X. Schwab

View All »Matching Part Numbers

Standard 30 mm Cage Plates

Cage System Overview

16 mm, 30 mm, and 60 mm Cage System Standards

Standard Threads

SM05-Threaded Cage Plate

SM1-Threaded Standard Cage Plates

SM1-Threaded Dual Flexure Cage Plate

SM1-Threaded Cage Plate with Flexure Clamps

SM1-Threaded 30 mm Cage Plate, Not Post Mountable

RMS-Threaded Cage Plate

C-Mount-Threaded Cage Plate

Standard Cage Plate for Ø1/2" Optics

Standard Cage Plate for Ø1" Optics

Dual Flexure Cage Plate for Ø1" Optics

30 mm Cage Plate with Ø1.2" Bore

30 mm Cage Plate with 35 mm Clear Aperture

Ø2" Round Cage Plates (30 mm Cage and SM1 Compatible)

30 mm Cage Plates for Premounted Aspheric and Achromatic Lenses

30 mm Cage Plates for Unmounted Optics from Ø5 mm to Ø20 mm

Blank Cage Plate

Optical Cage Plate Gasket

Cage Plate Stops for ER Rods

Alignment Plates for 30 mm Cage Systems