Vacuum-Compatible Right-Angle Brackets

  • Stably Mount Optomechanics at 90°
  • Counterbored 1/4" (M6) Slots and/or 1/4"-20 (M6 x 1.0) Holes for Mounting
  • Vacuum-Compatible to >10-6 Torr


Right-Angle Bracket with Counterbored Slots


Slim Right-Angle Bracket with Counterbored Slot & 1/4"-20 Tapped Holes

Application Idea

AB90CV Brackets Hold a
MB6U Breadboard at 90°


Right-Angle Bracket with Counterbored Slots & 1/4"-20 Tapped Holes

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Vacuum Specifications
Vacuum Compatibility
as Packageda
>10-6 Torr
Material 6061-T6 Aluminum
Outgassing Rate at 20 °C 7.6 x 10-9 Torr-Liters/s/cm2
Packaging Double Vacuum Bagged
  • This is the pressure at which these components can be used with no additional processing. They can be used at even lower pressures with additional cleaning and processing.

Additional Vacuum-Compatible Components

Many of our other optomechanical components can be special ordered for vacuum use. Contact for details.


  • Vacuum-Compatible Versions of Right-Angle Mounting Adapters
  • Compatible Down to 10-6 Torr Environments Directly Out of the Packaging
  • Shipped Double Vacuum Bagged for Cleanroom Use

Thorlabs' Vacuum-Compatible Right-Angle Brackets assist in creating sturdy three-dimensional optomechanical assemblies. They can be used directly with mounted optomechanics or as supports for larger structures. These brackets are fabricated from 6061-T6 aluminum for vacuum and cleanroom use. All components are packaged in double airtight bags for cleanroom and vacuum chamber applications. We also offer cap screws, setscrews, and washers for use with these items. 

Thorlabs also manufactures a variety of non-vacuum-compatible right-angle mouting adapters, available for purchase here.

Vacuum Compatibility Information
Our vacuum-compatible optomechanics are chemically cleaned and prepared for vacuum applications before packaging. They are compatible directly out of the packaging with vacuum environments down to 10-6 Torr. With additional cleaning and processing, they can be used at even lower pressures, only limited by the outgassing rate of the aluminum (see the table to the upper right). The material properties of the aluminum and the cleaning methods completed by the end user should be used to determine the appropriateness of these products and materials in a specific vacuum system.

We also offer other optomechanical components which may be used in vacuum applications, such as Ø1/2" and Ø1" Post Systems. We also offer Unanodized Aluminum Breadboards, which may be used in vacuum applications after undergoing cleaning and processing by the end user.

Product Image
(Click to Enlarge)
Item # AB90V AB90HV AB90AV(/M) AB90CV(/M)
Counterbored Mounting Slots Two 1/4" (M6) Slots One 1/4" (M6) Slot
Tapped Holes None Six 1/4"-20 (M6)
Holes per Side
Three 1/4"-20 (M6)
Holes on One Side
Dimensions (L x W x H)
[Click for Mechanical Drawing]
2.00" x 1.50" x 2.00"
(50.8 x 38.1 x 50.8 mm)
2.00" x 0.75" x 1.58"
(50.8 x 19.1 x 40.0 mm)
2.00" x 1.50" x 2.00"
(50.8 x 38.1 x 50.8 mm)
2.00" x 0.75" x 2.00"
(50.8 x 19.1 x 50.8 mm)

Insights into Best Lab Practices

Scroll down to read about a practice we follow when setting up lab equipment.

  • Washers: Using Them with Optomech

Click here for more insights into lab practices and equipment.


Washers: Using Them with Optomech

Washers should be placed between bolts and slots
Click to Enlarge

Figure 2: Install washers before inserting bolts into slots to protect the slot from damage. The rounded, smooth side of the washer should be placed against the slot, and the rough, flat side should be in contact with the bolt head. The smooth surface is designed to translate easily across the anodized surface, without harming it. The BA2 base is illustrated.
Washers distribute force of bolt heads
Click to Enlarge

Figure 1: The diameter of the washer is 35% larger than that of the bolt head. This results in over a six fold increase in overlap area with the slot of a BA2 base. By distributing the force of the bolt over a larger area, the washer help prevent gouging of the slot.

The head of a standard cap screw is not much larger than the major diameter of the thread (Figure 1). For example, a 1/4"-20 screw has a head diameter between 0.365" and 0.375" and the clearance hole diameter for the threads is 0.264".

When the screw is tightened directly through the clearance hole to secure the device, the force is applied to the edge of the through hole, often cutting into the material (Figure 1).

Once the material is permanently deformed, the screw head will want to fall back into the gouged groove, thereby moving the device back to that location when attempting to make fine adjustments.

A device with a circular through hole is not meant to translate around the screw thread so the deformation is not expected to be a problem.

However, a slot should provide the ability to secure the device anywhere along the length for the lifetime of the part. Using a washer distributes the force away from the slot edge to decrease the chance of deforming the slot and extending the lifetime of the part. Figure 1 illustrates the difference a washer can make. The contact area between the slot of a BA2 base and a 0.27" diameter cap screw is 0.010 in2. When a 0.5" diameter washer is used the contact area is 0.064 in2, which is over six times larger.

When using a Thorlabs washer, there are two distinct sides (Figure 2). One side is flat and rough and the other is curved and polished. The curved and polished side should be placed against the device, which has an anodized surface.

As the screw tightens, the screw head can force the washer to spin against the anodized coating.

If the flat side is pressed down against the anodization, the friction created by the rough flat side can scratch the anodized aluminum. However, if the curved side is facing down, the smooth surface has less friction leading to less scratches and extending the visual appearance of the device.

Date of Last Edit: Dec. 4, 2019

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Vacuum-Compatible Right-Angle Brackets for 1/4"-20 (M6) Cap Screws

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