Ø1/2" Specialty Post Holders


Ø1/2" Specialty Post Holders

  • Two-Line Contact with Mounting Post for Stability
  • Close-Approach Post Holders Allow Two Ø1/2" Posts to Touch
  • Translating Post Holders Provide Non-Rotating Height Adjustment


  • Close Approach Post Holders Allow Two Ø1/2" Posts to be Mounted in Contact with Each Other
  • Translating Post Holders Provide 0.025" (0.635 mm) Translation per Actuator Ring Rotation
  • Mounting Options to Secure Post Holders to an Optical Table or Breadboard

Thorlabs' selection of specialty post holders provide mounting solutions for unique circumstances. For applications where space is limited, consider our Close-Approach Post Holders that have a minimal profile, which enables two posts to be in contact with each other. Alternatively, if your application could benefit from post holders that offer fine adjustment, our Translating Post Holders provide up to 0.65" (16.51 mm) of height adjustment with 0.025" (0.635 mm) of adjustment per revolution of the actuator ring.

These Ø1/2" post holders feature and extra wide square relief cut machined vertically along the length of the part, as shown in the drawing to the right. This channel provides a highly-stable two-line contact between the post and post holder. Other post holder designs that do not have a relief cut provide less holding power, which leads to a downward drift in the post's position with time.

Table clamps and a swivel base allow the close-approach and translating post holders to be mounted to an optical table or breadboard, respectively. We also offer replacement spring-loaded, hex locking thumbscrews to secure the post in the holder.


Close-Approach Post Holders


  • Mount Two Ø1/2" Posts in Contact with Each Other
  • Cutaway Design with Two Lines of Contact
  • Post can Pass Through Base, Enabling Minimum Beam Height
  • Secure to the Optical Table with a CL6 or CL8 Clamp

Close-Approach Post Holders are designed for use on congested optical tables or when multiple components need to be placed in close proximity to each other. These post holders feature a cutaway design that provides two lines of contact for stable mounting, enables the same height adjustment of a standard post holder, and allows two Ø1/2" posts to be positioned very closely, or even in direct contact with each other, as shown in the image to right. They can be secured to the table using a CL6 or CL8 table clamp (sold below) and are compatible with all Ø12 mm, Ø12.7 mm, and Ø1/2" optical posts. Each imperial (metric) post holder comes with a TS25H 3/16" (TS6H/M 5 mm) hex spring-loaded thumbscrew.

In addition to the cutaway feature, the wall thickness on our close-approach post holders is 0.063” (1.6 mm) less than that found on our traditional post holders. Consequently, these post holders also allow closer positioning of three or more post holders than our standard post holders .


Table Clamps

The CL6 and CL8 table clamps allow the close-approach posts (sold above) to be secured to a optical table or breadboard. While the CL6 has a wedged tip, the CL8 has a V-shaped tip that provides two-point contact with the perimeter of the post and a rounded edge that increases the contact area along the optical table or breadboard.


Ø1/2" Translating Post Holders


  • Two Sizes and Adjustment Ranges Available
  • Non-Rotating Height Control: 0.65" (16.5 mm) for PH3T, 0.45" (11.3 mm) for PH2T
  • 0.025" (0.635 mm) of Translation per Revolution of Adjustment Ring

Our Translating Post Holders provide lockable, non-rotating height adjustment with convenient one-handed operation. An aluminum thumbscrew with a spring-loaded plunger provides holding force while the wide, square relief cut within the Ø1/2" post bore offers stable two-line contact. A knurled adjustment ring actuates the non-rotating height adjustment, which offers 0.025" (0.635 mm) of translational adjustment per revolution. Once the desired position is achieved, the entire mechanism can be locked using the lower thumbscrew and the locking hex socket on the upper thumbscrew. These post holders can be used with the Swivel Base Adapter featured below.


Swivel Base Adapter


  • Convert Your Existing Post Holders into UPH-Style Mounts
  • 360° Swiveling Base Fastens to Existing PH-Series Post Holders via a 1/4"-20 (M6) Cap Screw
  • Magnets in Base Provide Holding Force Prior to Fastening to an Optical Table

Our 360° swivel base adapter is compatible with the translating post holders (sold above) and minimizes the amount of time it takes to assemble an optical system. In addition, the swivel design is ideal for applications that require a large number of components to be packed into a small area. When our translating posts (featured directly above) are used with the UPHA adapter, the combination is nearly that of our very popular, non-translating UPH Series of Post Holders, which have an attached swivel base; however, unlike with the UPH series post holders, the adapter would prevent the translating post from touching the table.


1/4"-20 and M6 x 1.0 Thumbscrews for Post Holders


Spring-Loaded Hex Locking Thumbscrews (TS25H and TS6H/M): These anodized aluminum thumbscrews have spring-loaded, completely retractable Delrin™ tips that provide sufficient force on a post to hold it in place as final positional adjustments are being made. They can then be locked into place using a 3/16" or 5 mm balldriver to prevent any further movement of the post. The hex size is also engraved on the face of the thumbscrew, thereby enabling easy identification in the lab.

The TS25H is 1/4"-20 threaded for compatibility with our imperial Ø1/2" Post Holders, while the TS6H/M is M6 threaded for compatibility with our metric post holders. Please note that we do not recommend using an L wrench to tighten the thumbscrew in place, as this may break off the screw head. Recommended max torque: 28 in·lbs.



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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