Ø1.5" Post Basics


  • Solid Stainless Steel Construction
  • Stackable Design Provides Flexibility for Rigid Structures
  • Wide Range of Accessories Available

1/4"-20 Tapped Holes On Both Ends
(M6 Taps on Metric Versions)

Ø1.5" Post Spacers

1/4" (M6) Counterbores
(4 Top, 1 Bottom)

1/4" (M6) Counterbored Slots
1/4"-20 Center Tap (M6 Tap in PB2/M)

PB4

PB1

PB2

PS10M

PS7M

PS4M

PS1M

P14

P12

P10

P8

P6

P5

P4

P3

P2

P1.5

P1

PF175B Clamping Fork Securing a Ø1.5" Post with a PB4 Base Adapter

Related Items


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Our Ø1.5" Mounting Posts, which are fabricated from nonmagnetic 303 stainless steel, offer a wide range of basic building blocks for assembling large, rigid, 3D structures. The post products detailed on this page are the most essential construction elements onto which a host of accessories can be fastened. The solid stainless steel construction of our posts, post spacers, and post bases are complimented by large-diameter relief cuts at end interface points to provide exceptional strength and rigidity.

The stackable P-Series Posts and Post Spacers can be combined to offer a wide range of achievable mounting heights, while the P-Series Bases offer versatility when fastening posts to an optical table. A 1/4"-20 (M6) tapped hole in each post end provides sufficient clamping strength to join to posts, effectively making them one longer rigid post.


Posted Comments:
joseph.gallagher  (posted 2016-09-28 08:18:23.207)
The solidworks files for all the metric posts will not load, file error. I do not have this problem with any other product I tried from the site
jlow  (posted 2016-09-28 11:19:54.0)
Response from Jeremy at Thorlabs: The SolidWorks files were created using SolidWorks 2016 and it will not open on older version of SolidWorks. To get around that, you can download and use the STEP files instead.
Thorlabs  (posted 2010-12-07 10:00:31.0)
Response from Javier at Thorlabs to Vorvick: Thank you for following up with us. We will develop a solution in order to prevent deflection of the fork under the load of the screw. Please contact us at techsupport@thorlabs.com with your contact information so that we can keep you updated.
user  (posted 2010-12-06 20:39:19.0)
A response to Adam for Vorvick. Your are correct that the fork is bowing, but this really has nothing to do with the 3-point contact as you mentioned, rather it is caused by simple deflection of the fork under the load of the screw. In this case the fork bowed so much that the mid portion made contact with the mounting surface (optical table) and thus made it not usable. I suspect that this fork is made of aluminum and that combined with small clearance will casue this problem.
apalmentieri  (posted 2010-02-02 20:07:28.0)
A response from Adam at Thorlabs to Vorvick: I would like to get more information about the clamping fork is being used. From the description, it almost sounds like you are experiencing a bowing issue which should not happen due to the three point contact that the design permits. I will email you directly to get more information.
vorvick_c  (posted 2010-02-02 00:25:33.0)
fork is too flexible - touches table where the screw is - defeats the purpose - having to redo my setup without it.
siddiqi  (posted 2009-08-22 17:05:06.0)
For all post types -- it would be extremely useful if the posts were marked (e.g. laser etching) with length, diameter, and tapped hole size/pitch on the side (and ends if possible). Spacers could be marked on their faces. A 2 inch post looks an awful lot like a 50 mm post, and a 1/4-20 tap looks a lot like an M6. Labels would ensure that the correct part is pulled out of the drawer the first time...

Ø1.5" Posts

Overhead Shelf Clamp
Click to Enlarge

 Our Ø1.5" posts can also be used to mount our Post-Mounted ScienceDesk™ shelves, brackets, and monitor mount.
Metric Post Top
Click to Enlarge

Top of Metric Ø1.5" Post.
Imperial Post Top
Click to Enlarge

Top of Imperial Ø1.5" Post.
  • Solid Nonmagnetic Stainless Steel Construction
  • Ideal for Large, Rigid, 3D Structures

These solid stainless steel Ø1.5" (Ø38 mm) P-series posts, offered in heights ranging from 1" (25 mm) to 14" (350 mm), are designed for constructing extremely rigid assemblies with demanding structural integrity requirements. The stackable design, which has 1/4"-20 (M6) tapped holes on both ends, allows the joining of multiple mounting posts to achieve an array of lengths. These posts have a thread depth between 0.375" (9.525 mm) and 0.400" (10.16 mm). Using a 3/16" (5 mm) balldriver inserted through the side clearance hole, sufficient torque can be achieved to securely tighten stacked posts. These posts also feature a large-diameter relief cut on both ends for mounting stability.

For ease in distinguishing between the imperial and metric versions, the tops and bottoms of the metric posts have a ring engraved on them, while the imperial posts have no such engraving (see images above on the right).

Post spacers are also available below to provide greater flexibility in height. Please note that if your application requires tighter tolerances than those offered by the P-series [±0.005" (±0.127 mm)] or height adjustability, we recommend using the BLP01 Adjustable Height Post.

Based on your currency / country selection, your order will ship from Newton, New Jersey  
+1 Qty Docs Part Number - Imperial Price Available
P1 Support Documentation
P1Ø1.5" Mounting Post, 1/4"-20 Taps, L = 1"
$21.54
Today
P1.5 Support Documentation
P1.5Ø1.5" Mounting Post, 1/4"-20 Taps, L = 1.5"
$24.35
Today
P2 Support Documentation
P2Ø1.5" Mounting Post, 1/4"-20 Taps, L = 2"
$28.95
Today
P3 Support Documentation
P3Ø1.5" Mounting Post, 1/4"-20 Taps, L = 3"
$36.52
Today
P4 Support Documentation
P4Ø1.5" Mounting Post, 1/4"-20 Taps, L = 4"
$42.20
Today
P5 Support Documentation
P5Ø1.5" Mounting Post, 1/4"-20 Taps, L = 5"
$48.70
Today
P6 Support Documentation
P6Ø1.5" Mounting Post, 1/4"-20 Taps, L = 6"
$54.11
Today
P8 Support Documentation
P8Ø1.5" Mounting Post, 1/4"-20 Taps, L = 8"
$59.79
Today
P10 Support Documentation
P10Ø1.5" Mounting Post, 1/4"-20 Taps, L = 10"
$75.21
Today
P12 Support Documentation
P12Ø1.5" Mounting Post, 1/4"-20 Taps, L = 12"
$87.39
Today
P14 Support Documentation
P14Ø1.5" Mounting Post, 1/4"-20 Taps, L = 14"
$97.39
Today
+1 Qty Docs Part Number - Metric Price Available
P25/M Support Documentation
P25/MØ1.5" Mounting Post, M6 Taps, L = 25 mm
$21.54
Today
P30/M Support Documentation
P30/MØ1.5" Mounting Post, M6 Taps, L = 30 mm
$24.35
Today
P50/M Support Documentation
P50/MØ1.5" Mounting Post, M6 Taps, L = 50 mm
$28.95
Today
P75/M Support Documentation
P75/MØ1.5" Mounting Post, M6 Taps, L = 75 mm
$36.52
Today
P100/M Support Documentation
P100/MØ1.5" Mounting Post, M6 Taps, L = 100 mm
$42.20
Today
P125/M Support Documentation
P125/MØ1.5" Mounting Post, M6 Taps, L = 125 mm
$48.70
Today
P150/M Support Documentation
P150/MØ1.5" Mounting Post, M6 Taps, L = 150 mm
$54.11
Today
P200/M Support Documentation
P200/MØ1.5" Mounting Post, M6 Taps, L = 200 mm
$59.79
Today
P250/M Support Documentation
P250/MØ1.5" Mounting Post, M6 Taps, L = 250 mm
$75.21
5-8 Days
P300/M Support Documentation
P300/MØ1.5" Mounting Post, M6 Taps, L = 300 mm
$87.39
Today
P350/M Support Documentation
P350/MØ1.5" Mounting Post, M6 Taps, L = 350 mm
$97.39
Today

Ø1.5" Post Spacers

  • Solid Nonmagnetic Stainless Steel Construction
  • Ideal for Achieving "In-Between" Post Lengths

These solid stainless steel Ø1.5" (Ø38 mm) post spacers are designed to achieve post heights that are between those offered by any two P-Series posts. For example, a post height of 28 mm is achieved simply by attaching a PS3M (3 mm post spacer) to a P25/M (25 mm post). The spacer provides a center-located 1/4" (M6) clearance hole for access to the P-series posts as well as a large-diameter relief cut on both spacer ends for mounting stability. Please note that for applications requiring tight height tolerances, we recommend using a BLP01 Adjustable Height Post.

Based on your currency / country selection, your order will ship from Newton, New Jersey  
+1 Qty Docs Part Number - Universal Price Available
PS1M Support Documentation
PS1MMounting Post Spacer, Height = 1 mm
$12.66
Today
PS2M Support Documentation
PS2MMounting Post Spacer, Height = 2 mm
$11.03
Today
PS3M Support Documentation
PS3MMounting Post Spacer, Height = 3 mm
$11.03
Today
PS1 Support Documentation
PS1Mounting Post Spacer, Height = 1/8"
$9.09
Today
PS4M Support Documentation
PS4MMounting Post Spacer, Height = 4 mm
$11.03
Today
PS5M Support Documentation
PS5MMounting Post Spacer, Height = 5 mm
$9.09
Today
PS6M Support Documentation
PS6MMounting Post Spacer, Height = 6 mm
$11.03
Today
PS2 Support Documentation
PS2Mounting Post Spacer, Height = 1/4"
$9.74
Today
PS7M Support Documentation
PS7MMounting Post Spacer, Height = 7 mm
$11.15
Today
PS8M Support Documentation
PS8MMounting Post Spacer, Height = 8 mm
$11.91
Today
PS9M Support Documentation
PS9MMounting Post Spacer, Height = 9 mm
$12.01
Today
PS10M Support Documentation
PS10MMounting Post Spacer, Height = 10 mm
$9.74
Today
PS3 Support Documentation
PS3Mounting Post Spacer, Height = 1/2"
$10.83
Today
PS15M Support Documentation
PS15MMounting Post Spacer, Height = 15 mm
$10.83
Today
PS4 Support Documentation
PS4Mounting Post Spacer, Height = 3/4"
$11.46
Today
PS20M Support Documentation
PS20MMounting Post Spacer, Height = 20 mm
$11.46
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Base Adapters and Clamping Fork for Ø1" Post Holders and Ø1.5" Posts

Clamping Fork with Pedestal Post
Click to Enlarge

The PF175B fork is used to secure a Ø1.5" post to an optical table with a PB4 base.
P2 Clamping Fork with PB4
A Ø1.5" post is converted to a pedestal-style post with a PB4 base adapter.
PB4R Magnetic Base
Click to Enlarge

The PB4R(/M) has a 3/16" (5 mm) hex socket and four magnets in the base.
  • PB4(/M) and PB4R(/M) Adapters Convert Ø1.5" Posts to Pedestal-Style Mounts
  • Clamping Forks Secure Pedestal-Style Mount to a Breadboard or Optical Table
    • Three Counterbored Slot Options:
      • 0.85" (21.6 mm), 1.25" (31.8 mm), or 2.12" (53.8 mm)
    • Swivel Fork 360° to Select Most Convenient Mounting Hole
    • Available Individually or in Packs of 5

Pedestal Base Adapters
The PB4(/M) and PB4R(/M) pedestal base adapters feature a 1/4"-20 (M6)-threaded stud, which fits into the bottom of our Ø1.5" posts to convert them into pedestal-style mounts. Made from solid 303 stainless steel with a 1.85" (47.0 mm) outer diameter, these adapters allow these posts to be used with our clamping forks. The PB4(/M) can be tightened onto the post or postholder using a 1/8" (3 mm) hex key or ball driver, while the PB4R(/M) has a 3/16" (5 mm) hex socket as well as four high strength magnets in the base that are sufficiently strong to securely hold the base in place without clamping to an optical table.

Clamping Forks
The PF85B, PF125B, and PF175B clamping forks are designed to provide exceptional clamping force when used with our Ø1.5" posts that have been adapted using the PB4(/M) or PB4R(/M) pedestal bases. These clamping forks can also be used with our Ø1" post holders or BLP01 adjustable-height post without any need for the PB4(/M) or PB4R(/M) bases.

Made from stainless steel, these clamping forks create three points of contact with the table for high stability. The counterbored slots for 1/4"-20 (M6) cap screws allow the most convenient mounting hole to be selected. For flexibility in the positioning of post assemblies, Thorlabs offers three sizes: the PF85B fork has a 0.85" (21.6 mm) long counterbored slot, the PF125B fork has a 1.25" (31.8 mm) long counterbored slot, and the PF175B fork has a 2.12" (53.8 mm) long counterbored slot. 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.

These clamping forks are available idividually or in packs of five.

Based on your currency / country selection, your order will ship from Newton, New Jersey  
+1 Qty Docs Part Number - Imperial Price Available
PB4 Support Documentation
PB4Ø1.85" Studded Pedestal Base Adapter, 1/4"-20 Thread
$13.74
Today
PB4R Support Documentation
PB4RNEW!Ø1.85" Magnetic Studded Pedestal Base Adapter, 1/4"-20 Thread
$25.00
Today
+1 Qty Docs Part Number - Universal Price Available
PF85B Support Documentation
PF85BNEW!Clamping Fork for Ø1.5" Pedestal Post or Post Pedestal Base Adapter, 0.85” Counterbored Slot, Universal
$12.00
Today
PF85B-P5 Support Documentation
PF85B-P5NEW!Clamping Fork for Ø1.5" Pedestal Post or Post Pedestal Base Adapter, 0.85” Counterbored Slot, Universal, 5 Pack
$55.00
Today
PF125B Support Documentation
PF125BNEW!Clamping Fork for Ø1.5" Pedestal Post or Post Pedestal Base Adapter, 1.25” Counterbored Slot, Universal
$15.00
Today
PF125B-P5 Support Documentation
PF125B-P5NEW!Clamping Fork for Ø1.5" Pedestal Post or Post Pedestal Base Adapter, 1.25” Counterbored Slot, Universal, 5 Pack
$70.00
Today
PF175B Support Documentation
PF175BClamping Fork for Ø1.5" Pedestal Post or Post Pedestal Base Adapter, 2.12” Counterbored Slot, Universal
$17.00
Today
PF175B-P5 Support Documentation
PF175B-P5Clamping Fork for Ø1.5" Pedestal Post or Post Pedestal Base Adapter, 2.12” Counterbored Slot, Universal, 5 Pack
$80.00
Today
+1 Qty Docs Part Number - Metric Price Available
PB4/M Support Documentation
PB4/MØ1.85" Studded Pedestal Base Adapter, M6 x 1.0 Thread
$13.74
Today
PB4R/M Support Documentation
PB4R/MNEW!Ø1.85" Magnetic Studded Pedestal Base Adapter, M6 x 1.0 Thread
$25.00
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Ø1.5" Post Bases

PB1
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) cap screw. Four 1/4" (M6) counterbored holes are provided at the proper spacing for compatibility with an imperial or metric optical table or optical breadboard. The base contains a mounting hole for 1" or 25 mm centers.

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.

Pedestal Base Adapter
The PB4(/M) and PB4R(/M) pedestal base adapters feature 1/4"-20 (M6)-threaded studs, which fit into the bottom of our Ø1.5" posts to convert them into pedestal-style mounts. The PB4(/M) can be tightened onto the post or postholder using a 1/8" (3 mm) hex key or ball driver, while the PB4R(/M) has a 3/16" (5 mm) hex socket. The PB4R(/M) also has four high strength magnets in the base that are sufficiently strong to securely hold the base in place without clamping to an optical table. The adapters are made from solid 303 stainless steel with a 1.85" (47.0 mm) outer diameter. They can be secured to a breadboard using the PF85B, PF125B, or PF175B clamping fork or CL8 clamp (sold separately below).

Based on your currency / country selection, your order will ship from Newton, New Jersey  
+1 Qty Docs Part Number - Imperial Price Available
PB2 Support Documentation
PB2Mounting Post Base, Ø2.40" x 0.50" Thick
$29.76
Today
PB4 Support Documentation
PB4Ø1.85" Studded Pedestal Base Adapter, 1/4"-20 Thread
$13.74
Today
PB4R Support Documentation
PB4RNEW!Ø1.85" Magnetic Studded Pedestal Base Adapter, 1/4"-20 Thread
$25.00
Today
+1 Qty Docs Part Number - Universal Price Available
PB1 Support Documentation
PB1Mounting Post Base, Ø2.48" x 0.40" Thick
$26.18
Today
+1 Qty Docs Part Number - Metric Price Available
PB2/M Support Documentation
PB2/MMetric Mounting Post Base, Ø61 mm x 12.7 mm Thick
$29.76
Today
PB4/M Support Documentation
PB4/MØ1.85" Studded Pedestal Base Adapter, M6 x 1.0 Thread
$13.74
Today
PB4R/M Support Documentation
PB4R/MNEW!Ø1.85" Magnetic Studded Pedestal Base Adapter, M6 x 1.0 Thread
$25.00
Today

Ø1.5" Pedestal Post Clamp

Post Clamp Clamping a Pedestal Post
Click to Enlarge

CL8 Clamps Securing P4 Ø1.5" Post on PB4 Pedestal
CL8 Cross Section
Click to Enlarge

CL8 Cross-Sectional View
  • Compatible with Ø1" and Ø1.5" Posts
  • Two-Point Contact with Pedestal Post Perimeter
  • Line Contact on Table for More Secure Clamping Force

Thorlabs' CL8 pedestal post clamp secures our Ø1" and Ø1.5" pedestal posts to an optical table or breadboard. Its V-shaped tip provides two-point contact with the post perimeter and its rounded edge increases the contact area along the table.

Based on your currency / country selection, your order will ship from Newton, New Jersey  
+1 Qty Docs Part Number - Universal Price Available
CL8 Support Documentation
CL8Ø1" and Ø1.5" Pedestal Post Table Clamp
$8.55
Today

Post Position Retainers

  • Mark the Position of Ø1" and Ø1.5" Posts within an Optical System
  • Realignment Based on Two Contact Points
  • Third Contact Point for Realigning Square Components
  • Swivel Head Retainer Available with 200° of Rotation

Thorlabs' Position Retainers can be used to realign posts that have been removed from an optical system. They act as markers on the breadboard or optical table in the event that you need to remove a post from your setup. The two dots near the ends of the outer arms of the retainer mark the two points of post contact. 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 our retainers with square components, click here.

The RSPC Fixed Retainer is a compact solution for use with Ø1" and Ø1.5" Pedestal Posts. The post should be independently clamped down before aligning the RSPC retainer. After the retainer is mounted in place, the post can be removed from the setup and then later placed back into the same position.

The RSPCS(/M) Swivel Retainer features a swivel head for 200° of rotational adjustment. This allows for access to additional mounting holes on the breadboard. The post should be independently locked before aligning RSPCS(/M) retainer. Partially loosen the tension adjuster screw and then mount the retainer to a breadboard tap while maintaining contact with the post. Lastly, tighten the tension adjuster screw. After this the component can be removed from the setup and then later placed back into the same position.

Post Retainer Mounted Directly to Optical Table
Click to Enlarge
View Imperial Product List
Item #QtyDescription
Imperial Product List
RSPC1Fixed Position Retainer
PB41Ø1.85" Studded Pedestal Base Adapter, 1/4"-20 Thread
PF1751Clamping Fork for Ø1.5" Pedestal Post or Post Pedestal Base Adapter, Universal
P31Ø1.5" Mounting Post, 1/4"-20 Taps, L = 3"
SH25S05011/4"-20 Stainless Steel Cap Screw, 1/2" Long, 25 Pack
W25S05011/4" Washer, M6 Compatible, Stainless Steel, 100 Pack
View Metric Product List
Item #QtyDescription
Metric Product List
RSPC1Fixed Position Retainer
PB4/M1Ø1.85" Studded Pedestal Base Adapter, M6 x 1.0 Thread
PF1751Clamping Fork for Ø1.5" Pedestal Post or Post Pedestal Base Adapter, Universal
P75/M1Ø1.5" Mounting Post, M6 Taps, L = 75 mm
SH6MS121M6 x 1.0 Stainless Steel Cap Screw, 12 mm Long, 25 Pack
W25S05011/4" Washer, M6 Compatible, Stainless Steel, 100 Pack
RSPC Position Retainer
Optical Post Positioner Secured by CL6 Clamp
Click to Enlarge
View Imperial Product List
Item #QtyDescription
Imperial Product List
RSPCS1Position Retainer with Swivel Head, 3/16" Hex Tension Adjuster
PB41Ø1.85" Studded Pedestal Base Adapter, 1/4"-20 Thread
PF1751Clamping Fork for Ø1.5" Pedestal Post or Post Pedestal Base Adapter, Universal
P31Ø1.5" Mounting Post, 1/4"-20 Taps, L = 3"
CL61Table Clamp, RLA Series Optical Rails
SH25S05011/4"-20 Stainless Steel Cap Screw, 1/2" Long, 25 Pack
W25S05011/4" Washer, M6 Compatible, Stainless Steel, 100 Pack
View Metric Product List
Item #QtyDescription
Metric Product List
RSPCS/M1Position Retainer with Swivel Head, 5 mm Hex Tension Adjuster
PB4/M1Ø1.85" Studded Pedestal Base Adapter, M6 x 1.0 Thread
PF1751Clamping Fork for Ø1.5" Pedestal Post or Post Pedestal Base Adapter, Universal
P75/M1Ø1.5" Mounting Post, M6 Taps, L = 75 mm
CL61Table Clamp, RLA Series Optical Rails
SH6MS121M6 x 1.0 Stainless Steel Cap Screw, 12 mm Long, 25 Pack
W25S05011/4" Washer, M6 Compatible, Stainless Steel, 100 Pack
RSPCS Swiveling Position Retainer
Based on your currency / country selection, your order will ship from Newton, New Jersey  
+1 Qty Docs Part Number - Imperial Price Available
RSPCS Support Documentation
RSPCSPosition Retainer with Swivel Head, 3/16" Hex Tension Adjuster
$33.60
Today
+1 Qty Docs Part Number - Universal Price Available
RSPC Support Documentation
RSPCCustomer Inspired! Fixed Position Retainer
$9.95
Today
+1 Qty Docs Part Number - Metric Price Available
RSPCS/M Support Documentation
RSPCS/MPosition Retainer with Swivel Head, 5 mm Hex Tension Adjuster
$33.60
Today