Ø1/2" Post Clamps


Ø1/2" Construction Accessories

  • Compatible with Our Ø1/2" Posts
  • Essential Building Blocks for Complex, Rigid Structures
  • All Through Holes are Double-Bored for two Lines of Post-to-Mount Contact


  • Rigid Construction Accessories Required for Many Complex 3D Assemblies
  • Angle Clamp Options
    • Fixed 45°
    • Fixed 90° Ø1/2" or Ø1" Mounting Options
    • Fixed 180°
    • Continuous 360°
  • Mounting Joist Provides Space-Saving Platform for Multiple Optical Mounts

When space is at a premium, Thorlabs' Angle Clamps and Mounting Joists provide great space-saving solutions. Our angle clamps give the user the ability to orient our Ø1/2" posts in multiple directions and provide rigid, stable and compact structures that can meet many laboratory needs. The double-bored mounting holes ensure two lines of stable contact, while the aluminum thumbscrews securely fasten the posts in place.

Thorlab's Mounting Joists provide even more space-saving options. The compact joist can be used to mount multiple optical elements close together, which alleviates the need for multiple posts and posts holders. These versatile joists can also offset a post from the mounted optic in order to squeeze the optic into tight areas. The two joist designs provide adaptable laboratory solutions to crowded table problems.


Angle Clamps for Ø1/2" Posts


  • Rigid Construction Accessories Required for Many Complex 3D Assemblies
  • Double Bored Through Holes for Stable Two Line Contact
  • Aluminum Thumbscrew Provides Secure Holding Force for Locking

Thorlabs' Angle Clamps securely fasten our Ø1/2” posts at precise angles (45°, 90° or 180°) to one another. In addition to the fixed angle options, we also offer a variant for 360° continuous adjustment (SWC). The holes of these clamps are double bored to provide two lines of stable contact. The RA180(/M) has one double-bored hole and a 1/4"-20 (M6) thread on the bottom, which allows this clamp to be directly threaded onto a post. The aluminum thumbscrews located at either side of the clamps secure the Ø1/2” posts in place once the desired position is achieved.

Product Image
(Click for Zoom)
Item # RA45(/M) RA90(/M) RA180(/M) SWC(/M)
Clamp Angle 45° 90° 180° Continuous 360°


Ø1" to Ø1/2" Right-Angle Post Clamp


  • Mounts a Ø1/2" Post Perpendicular to a Ø1" Post
  • Flexure Mechanism Secures Right-Angle Clamp to Ø1" Post
  • Thumbscrew Secures Ø1/2" Post
  • Imperial and Metric Versions Available

The RA90RS clamp allows a Ø1/2" TR post to be mounted perpendicularly to a Ø1.0" RS post. The design, which is based off of the RA90 Right-Angle Post Clamp featured above, combines a highly stable clamp flexure lock with a thumbscrew locking mechanism to provide a solution that enables a Ø1/2" post to be mounted perpendicular to a Ø1" post. The center-to-center distance between the Ø1.0" and Ø1/2" posts is 1" for the imperial version (25.0 mm for the metric version).


Mounting Joists

  • Compatible with Thorlabs' Ø1/2" and Ø1" Posts
  • Space-Saving Design Allows the Mounting of Multiple Optical Elements on One Post
  • Options for Center-Mounting or Offset-Mounting

Thorlabs’ Mounting Joists provide valuable space-saving mounting options, ideal for crowded optical tables or breadboards. These mounts are compatible with our Ø1/2” and Ø1” posts and allow multiple optics may be mounted close together on a single joist, eliminating the need for multiple posts and post holders.

The PJ301(/M) enables centered-mounting (optics may be placed on both sides of post center) and features a centered, counterbored hole for an 8-32 (M4) cap screw for post mounting and counterbored slots for an 8-32 (M4) cap screw and #8 nut (M4 nut). This joist allows an optic to be offset by 0.40" - 1.40" (10.16 - 35.56 mm) from post center.

The PJ302(/M) enables offset-mounting (optics may be offset to one side only) and features counterbored slots for an 8-32 (M4) cap screw for post mounting and a counterbored slot for an 8-32 (M4) cap screw and #8 nut (M4 nut). This joist allows an optic to be offset by 0.40" - 2.70" (10.16 - 68.58 mm) from post center.




Our Mission is to accelerate the advancement of optical technology for precision measurements and their applications from the table tops of research laboratories to standard use in communication and high technology industries. Our aim is to serve our customers. Our hope is to create a place for highly skilled people in an open environment

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