Ø1" and Ø1.5" Post Bases


Post Bases

  • Rigid One-Piece Construction for Superior Stability
  • Converts Our Large Posts into "Pedestal Style" Mounts


  • Convert Ø1" (RS-Series) and Ø1.5" (P-Series) Posts into Pedestal Style Posts
  • All Bases Provide Large Bottom Relief Cuts for Exceptional Stability
  • Clamping Forks Offer Exceptional Positional Mounting Flexibility

Ø1.5" Post Bases
The PB1 and PB2 fasten directly to a Ø1.5" P-Series Post via 1/4"-20 (M6) cap screws placed through the bottom-located counterbores in the base. The PB1 offers four top-located 1/4" (M6) counterbores located on 1" centers for compatibility with both Imperial and Metric optical tables and breadboards. The PB2 provides four 1/4" (M6) counterbored slots for additional positional freedom where alignment on an optical table does not conform to standard table mounting hole spacing.

The PB4 provides even greater positional flexibility by fastening directly to a Ø1.5" posts via the provided 1/4"-20 (M6) stud, converting a standard post into a "Pedestal Style" post. This pedestal configuration is directly compatible with the PF175 clamping fork which provides for the greatest overall positional flexibility when mounting to an optical table.

Ø1" Post Bases
The BE1 fastens directly to a Ø1" RS-Series Post via the provided 1/4"-20 (M6) stud, converting a standard Ø1" post into a Pedestal Style post. This pedestal configuration is directly compatible with our CF125 and CF175 solid stainless steel clamping forks which provide for the greatest overall positional flexibility when mounting to an optical table.


Base Adapters and Clamping Forks


  • Combine BE1 Adapter Converts Standard PH Series Post Holder into Pedestal-Style Mount
  • Clamping Fork Secures Pedestal-Style Mount to a Breadboard or Table
  • Two Sizes: CF125 (1.25" Counterbored Slot) and CF175 (1.75" Counterbored Slot)
  • Swivel Fork ±360° to Pick Up Most Convenient Mounting Hole

Pedestal Base Adapter
The BE1 fastens to the base of our standard PH Series Post Holders (as shown to the right) and RS Series Ø1" Pillar Posts to convert them into Pedestal-Style mounts. This combination provides a high degree of mounting flexibility. Note: Together, the BE1 Base Adapter and PH Series Post Holder provide nearly the same design to that of the PHxE Series Pedestal-Style Post Holder without the magnets in the base and through hole design.

Clamping Forks
Our solid stainless steel clamping forks are designed to provide exceptional clamping force when used with our pedestal-style posts and post holders. Use a 1/4"-20 (M6) cap screw and washer combination to lock down the base/fork combination. Please note that significant overtightening of clamping forks can deform the surface of an optical table, which can cause misalignment of components.


Ø1.5" Post Bases


This universal post base has a 1/4" (M6) Counterbored hole in the center that allows the base to be attached to a Ø1.5" mounting post using a 1/4"-20 (M6) caphead screw. Four 1/4" (M6) counterbored holes on 2" (50 mm) centers are provided for mounting the post base to an optical table or optical breadboard.

PB2 and PB2/M
These post bases have counterbored slots that allow for additional freedom in the placement of Ø1.5" mounting posts. The PB2 has a center-tapped 1/4"-20 hole while the PB2/M has a center-tapped M6 hole. The PB2/M has an identifying ring engraved around the tapped hole on the bottom face of the base. Use a 1/4"-20 (M6) setscrew to attach the PB2 (PB2/M) base to a Ø1.5" mounting post.


Ø1.5" Post Pedestal Base Adapter and Clamping Fork


Each PB4 (PB4/M) Pedestal Base Adapter has a threaded 1/4"-20 (M6) stud that is designed to thread onto the bottom of our P-Series Posts. For instance, the image to the right shows a P2 post with a PB4 Base. The PB4 adapter allows our PF175 clamping fork to be used to position the post assembly conveniently on your optical bench. This clamping fork creates three points of contact with the table for high stability.

Please note that significant overtightening of clamping forks can deform the surface of an optical table, which can cause misalignment of components and decrease stability of the clamping fork.


 Post Position Retainer


  • Re-Position Ø1" and Ø1.5" Posts within an Optical System
  • Re-Alignment Based on Two Contact Points
  • Third Contact Point for Realigning Square Components
  • 1.73" (43.8 mm) Long and 0.13" (3.2 mm) Thick

Thorlabs' RSPC Post Position Retainer is used to realign posts that have been removed from an optical system. It acts as a marker on the breadboard or optical table in the event that you need to remove a post from your setup. The two white dots engraved on the top surface of the outer arms of the retainer mark the two points of post contact. The RSPC was specifically designed for use with the Ø1" Pedestal Posts. The third dot, located within the V-groove, is for retaining the position of a square base or other squared-off component. For more information on using the RSPC with a square component.

Note: The RSPC Post Position Retainer can also be secured to an optical table or breadboard via the CL6 clamp. This clamp is useful in situations where the RSPC cannot be placed directly over a hole in the table. The photos below illustrate the RSPC being secured to an optical table both with an 8-32 cap screw and with the CL6 clamp.


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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