25 mm Optical Construction Rails

  • Build Enclosures and Other Rigid Mechanical Assemblies
  • Stock Lengths: 9" - 48" and 225 mm - 1200 mm
  • Custom Lengths and Raw Extrusions Available

Metric Indicator
by Tapped Hole
(One Side Only)


Black Anodized,
0.5 m Long, M6 Taps


Raw Aluminum,
2 m Long, No Taps

Alignment Hole
(4 Places)

Channel Accepts
T-Nuts, Rail Joiners,
or Enclosure Panels

1/4"-20 (M6) Tap
(Both Ends)

XE25 Series Rail

25.0 mm

25.0 mm

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  • 25 mm Square Construction Rails
  • Stock Lengths Range from 9" to 48" (Metric Lengths: 225 - 1200 mm)
  • Rail Channels Accommodate Mechanical Components
  • Custom Rail Lengths and Raw Extrusions Available

With a 25 mm x 25 mm profile, Thorlabs' XE25 Construction Rails are our most compact and lightweight option for building three-dimensional mechanical structures. They consist of extruded lengths of aluminum that feature channels on all four sides, as shown in the image at the top of the page. These channels make the rails mechanically compatible with other optomechanical components. For instance, by inserting T-Nuts into the channels, any 8-32 (M4) or 1/4"-20 (M6) optomechanical component can be fastened to the rail sides. The channels are also perfectly sized to hold enclosure panels made of black hardboard or plexiglass, as is done with our optical enclosures.

Our 25 mm rails are offered in pre-cut lengths from 9" to 48" (225 to 1200 mm) and are finished with a durable, black anodized coating. The centered 1/4"-20 (M6) tapped hole on both ends allows the rail to be mounted directly to a breadboard or optical table. Upon request, we can provide these anodized rails in custom lengths from 2.5" to 79" (50 to 2000 mm), or we can provide the raw rail extrusion in lengths up to 3 m (9.8'). For material properties including mass per meter, cross-sectional area, and second moment of area, please refer to the Engineering Specs tab.

Thorlabs' accessories for assemblies made of 25 mm rails include corner cubes and brackets, T-nuts, low-profile channel screws, breadboard mounting accessories, rail joiners, and a channel insert. In addition, we offer optical enclosures, enclosure accessories, laser safety fabric panels, and "do-it-yourself" tools like taps, tap guides, and drill guides for home-built XE25-based constructions.

Physical Properties of 25, 50, & 75 mm Rails
Rail Size 25 mm x 25 mm 50 mm x 50 mm 50 mm x 75 mm 75 mm x 75 mm
Rail Cross Section XE25 Rail Profile XE50 Rail Profile XE5075 Rail Profile XE75 Rail Profile
Mass/Length 0.811 kg/m 2.227 kg/m 2.959 kg/m 3.690 kg/m
Cross-Sectional Area 3.13 cm2 8.25 cm2 10.96 cm2 13.67 cm2
Moment of Areaa
X-Axis 1.68 cm4 23.9 cm4 33.9 cm4 96.4 cm4
Y-Axis 1.68 cm4 24.2 cm4 70.0 cm4 97.1 cm4
Aluminum Alloy 6000 Series 6063-T6
  • The second moment of area, also known as the area moment of inertia, of a beam is a physical property that represents the beam's ability to resist bending under load. This property takes into account the distribution of material and its distance from the specified axis.

Posted Comments:
hbabcock  (posted 2017-05-30 09:36:14.72)
Could you also sell rubber caps to protect the ends of these rails? This request is somewhat similar to your XE25C, except that this would be press on and would maybe extend 1/2" or so down the side of the rail.
tfrisch  (posted 2017-06-22 08:56:58.0)
Hello, thank you for contacting Thorlabs. While we do not have a press on cap, our breadboard feet may be suitable for your application. I will reach out to you directly to discuss them: https://www.thorlabs.com/newgrouppage9.cfm?objectgroup_ID=1867
tcohen  (posted 2012-05-14 17:22:00.0)
Response from Tim at Thorlabs: When adding the 25mm customized rail (XE25-CUSTRAIL) to your shopping cart, you are able to view the price and lead time. Currently, a typical lead time is approximately 3-4 weeks.
hwei  (posted 2012-05-14 16:16:20.0)
May I know when the 25mm Customized Rail will be available? Thanks.
tcohen  (posted 2012-03-02 17:49:00.0)
Response from Tim at Thorlabs to Andrew: Thank you for your feedback! I am discussing the introduction of a T-nut with a spring-loaded ball with our design team. We are always interested in customer feedback as inspiration for new products and we appreciate you contacting us with your idea.
andrew_yablon  (posted 2012-03-01 16:40:43.0)
I found product number 47065T226 from McMaster-Carr to be the best slide in T-nut because (1) it is 1/4-20 threaded; (2) it slides into the Thorlabs XE25 construction rails easily; and most importantly (3) it comes with a spring-loaded ball that holds the T-nut in place when the XE25 rail is vertical. Can Thorlabs introduce a (cheaper?) XE25 compatible T-nut that contains a spring-loaded ball like McMaster-Carr's part number 47065T226? Thanks, Andrew Yablon andrew_yablon@interfiberanalysis.com
Thorlabs  (posted 2011-01-17 14:34:04.0)
Response from Javier at Thorlabs to jeffrey.hendrixson: thank you very much for submitting your inquiry. If the connection between all the components is collinear, you can simply use 1/4"-20 setscrews; a 1" long setscrew at each junction would suffice. If the P14 posts are to be mounted perpendicularly with respect to the XE25L18, then you could use 1/4"-20 setscrews along with two XE25T1 T-nuts (one for each connection).
jeffrey.hendrixson  (posted 2011-01-15 07:50:47.0)
Do you make a product that would allow the XE25L18 connect between two P14 1.5" mounting posts?
Tyler  (posted 2008-06-06 12:43:22.0)
A response from Tyler at Thorlabs to Michael: I will have an application engineer send you a quote for 10 9" long rails. For a much faster response, we have a part number "XE25-CUSTRAIL" listed at the bottom of all the fixed rails in our price box. You simply need to put in a quantity and a length and it will generate a price on the spot. You can then buy the custom rails online or remove them from the basket and continue browsing.
michael.smith  (posted 2008-06-06 12:09:04.0)
I am interested in pricing information for the custom rail lengths. Is there a minimum order number? Im thinking of ordering something like 10 9" long rails.

25 mm Square Construction Rails

  • Black Anodized Finish
  • 1/4"-20 (M6 x 1.0) Tapped Holes on Both Ends
  • Custom Lengths Available

Our 25 mm rails have rail channels on all four sides for use in one-, two-, or three-dimensional constructions. These channels feature 6.5 mm openings and accept T-Nuts, rail joiners, and enclosure panels. Each rail end is tapped with a 1/4"-20 (M6 x 1.0) hole for compatibility with standard optomechanics.

The pre-cut rails are offered from stock in lengths ranging from 9" to 48" (225 mm to 1200 mm), with a tolerance of ±0.006" (±150 µm). If our pre-cut lengths do not suit your application, custom lengths from 2.5" - 79" (50 mm - 2000 mm) can be ordered by using the XE25-CUSTRAIL(/M) field in the price box below or contacting Technical Support.

As shown in the family image at the top of the page, metric rails are denoted by a small hole on one side of the extrusion, next to the M6 tapped hole.

Based on your currency / country selection, your order will ship from Newton, New Jersey  
+1 Qty Docs Part Number - Imperial Price Available
XE25L09 Support Documentation
XE25L0925 mm Square Construction Rail, 9" Long, 1/4"-20 Taps
XE25L12 Support Documentation
XE25L1225 mm Square Construction Rail, 12" Long, 1/4"-20 Taps
5-8 Days
XE25L15 Support Documentation
XE25L1525 mm Square Construction Rail, 15" Long, 1/4"-20 Taps
XE25L18 Support Documentation
XE25L1825 mm Square Construction Rail, 18" Long, 1/4"-20 Taps
5-8 Days
XE25L20 Support Documentation
XE25L2025 mm Square Construction Rail, 20" Long, 1/4"-20 Taps
5-8 Days
XE25L21 Support Documentation
XE25L2125 mm Square Construction Rail, 21" Long, 1/4"-20 Taps
XE25L24 Support Documentation
XE25L2425 mm Square Construction Rail, 24" Long, 1/4"-20 Taps
XE25L28 Support Documentation
XE25L2825 mm Square Construction Rail, 28" Long, 1/4"-20 Taps
XE25L30 Support Documentation
XE25L3025 mm Square Construction Rail, 30" Long, 1/4"-20 Taps
XE25L33 Support Documentation
XE25L3325 mm Square Construction Rail, 33" Long, 1/4"-20 Taps
XE25L36 Support Documentation
XE25L3625 mm Square Construction Rail, 36" Long, 1/4"-20 Taps
Lead Time
XE25L45 Support Documentation
XE25L4525 mm Square Construction Rail, 45" Long, 1/4"-20 Taps
5-8 Days
XE25L48 Support Documentation
XE25L4825 mm Square Construction Rail, 48" Long, 1/4"-20 Taps
XE25-CUSTRAILCustomized Rail from 2.5 to 79 inches , Enter custom Length
+1 Qty Docs Part Number - Metric Price Available
XE25L225/M Support Documentation
XE25L225/M25 mm Square Construction Rail, 225 mm Long, M6 Taps
XE25L300/M Support Documentation
XE25L300/M25 mm Square Construction Rail, 300 mm Long, M6 Taps
XE25L375/M Support Documentation
XE25L375/M25 mm Square Construction Rail, 375 mm Long, M6 Taps
XE25L450/M Support Documentation
XE25L450/M25 mm Square Construction Rail, 450 mm Long, M6 Taps
XE25L500/M Support Documentation
XE25L500/M25 mm Square Construction Rail, 500 mm Long, M6 Taps
5-8 Days
XE25L525/M Support Documentation
XE25L525/M25 mm Square Construction Rail, 525 mm Long, M6 Taps
XE25L600/M Support Documentation
XE25L600/M25 mm Square Construction Rail, 600 mm Long, M6 Taps
XE25L700/M Support Documentation
XE25L700/M25 mm Square Construction Rail, 700 mm Long, M6 Taps
XE25L750/M Support Documentation
XE25L750/M25 mm Square Construction Rail, 750 mm Long, M6 Taps
XE25L825/M Support Documentation
XE25L825/M25 mm Square Construction Rail, 825 mm Long, M6 Taps
XE25L900/M Support Documentation
XE25L900/M25 mm Square Construction Rail, 900 mm Long, M6 Taps
XE25L1125/M Support Documentation
XE25L1125/M25 mm Square Construction Rail, 1125 mm Long, M6 Taps
XE25L1200/M Support Documentation
XE25L1200/M25 mm Square Construction Rail, 1200 mm Long, M6 Taps
XE25-CUSTRAIL/MCustomized Rail from 50 to 2000 mm , Enter custom Length

25 mm Square Construction Rail, Raw Extrusion

  • Unanodized Extrusion for Custom Applications
  • 2 m (6.6') Length
  • Center Hole is Not Tapped

The XE25RL2 is an unanodized, rough-cut extrusion for customers who prefer to machine and finish their own rails. The center hole of the extrusion can be 1/4"-20 or M6 tapped without additional machining. Its aluminum construction makes it easy to machine in your own machine shop.

Upon request, we can supply this extrusion in lengths up to 3 m (9.8'). Please contact Technical Support for a quote.

Based on your currency / country selection, your order will ship from Newton, New Jersey  
+1 Qty Docs Part Number - Universal Price Available
XE25RL2 Support Documentation
XE25RL2Raw, Unanodized 25 mm Rail Extrusion, 2 m (6.6') Long