Vacuum-Compatible Ø1/2" Post System


  • Ø1/2" Post System Components for Vacuum Use
  • All Components are Shipped Double Vacuum Bagged
  • Constructed of 316, 304L, and A4 Stainless Steel and
    6061-T6 and 2024-T3 Aluminum

Ø1/2" Posts

TR3V

TR2V

TR1V

BA1V

Ø1/2" Post Holder Base

Vacuum-Compatible Ø1/2"
Post System: TR3V, PH3V, SS8S050V, and BA2V

PH2V

Ø1/2" Post Holder

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Additional Vacuum-Compatible Components

Many of our other Optomechanical Components can be special ordered for vacuum use. Contact techsupport@thorlabs.com for details.

Vacuum Post Holder Packaging
Click to Enlarge

All vacuum-compatible components are packaged inside a double vacuum bag.

Features

  • Vacuum-Compatible Versions of Popular Optomechanical Components
  • Ø1/2" Post System Includes Posts, Post Holders, Post Holder Bases, Thumbscrews, and Cap Screws
  • All Components Compatible with 10-6 Torr Environments Directly Out of the Packaging
  • Compatible with Lower Pressures with Additional User Processing
  • All Components are Shipped Double Vacuum Bagged for Cleanroom Use

This page features vacuum-compatible versions of our most popular optomechanical components. These components are fabricated from specially-selected grades of stainless steel and aluminum for vacuum and cleanroom use. As shown in the photo to the right, all components are packaged in double airtight bags for cleanroom and vacuum chamber applications. We offer cap screws, setscrews, and washers for use with these items. 

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 or stainless steel (see the Vacuum Specs tab or the Specs tables below). The material properties of the aluminum or stainless steel 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. Many of our Polaris Mirror Mounts are vacuum-compatible. We also offer Unanodized Aluminum Breadboards, which may be used in vacuum applications after undergoing cleaning and processing by the end user.

Vacuum Compatibility Specs

ItemØ1/2" PostsØ1/2" Post HoldersPost Holder BasesThumbscrewsVented Cap Screws & Washers
Vacuum
Compatibility
as Packageda
>10-6 Torr
Materials 304L Stainless Steel (Post)
316 Stainless Steel (Setscrew)
6061-T6 Aluminum (Post Holder)
2024-T3 Aluminum (Thumbscrew)
353NDPK Epoxyb
Low Vacuum Pressure Grease
6061-T6 Aluminum 2024-T3 Aluminum 316 Stainless Steel (Imperial)
A4 Stainless Steel (Metric)
Preparation and
Packaging
Chemically Cleaned and Double Vacuum Bagged
Aluminum / Stainless
Steel Outgassing
Rate at 20 °C
1.8 x 10-8 Torr-Liters/s/cm2 7.6 x 10-9 Torr-Liters/s/cm2 7.6 x 10-9 Torr-Liters/s/cm2 1.8 x 10-8 Torr-Liters/s/cm2
Additional
Vacuum
Compatibility
Information
- Grease Vapor Pressure:
10-13 Torr at 20 °C
10-5 Torr at 200 °C
Epoxy Meets Low Outgassing
Standards NASA ASTM E595
and Telcordia GR-1221
- - -
  • 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.
  • Click here to view the 353NDPK datasheet.

Insights into Best Lab Practices

Scroll down to read about a few things we consider when setting up lab equipment.

  • Washers: Using Them with Optomech
  • Bases: For Stability Orient the Side with the Undercut Down

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

 

Bases: For Stability Orient the Side with the Undercut Down

An undercut is machined into the bottom surface of bases like the BA2 (Figures 3 and 4). The undercut creates feet, which are called pads. For maximum stability, the base should be oriented with its pads in contact with the table or breadboard.

The top surface of the base does not have an undercut and is the intended mounting surface for components.

Mounting the base upside down could result in the base rocking on the table or breadboard, or the base may exhibit other mechanical instability.

The Pads are Flatter than the Top Surface
The undercut is key to the flatness of the pads. The pads are machined flat after the undercut is made.

Friction heats the pads during the processing step that provides them with a maximally flat profile. By reducing the surface area of the pads, the undercut reduces the amount of heat generated during this step.

It is beneficial to minimize the heat generated during machining. Metal expands when heated, and the uneven heating that occurs during machining can distort the dimensions of the part. If the dimensions of the part are distorted during machining, the part can be left with high spots and other undesirable features after it cools. This can cause instability and misalignment when using the part.

Precision Instruments and Devices have Pads
Another example of a component with pads is the LX10 linear stage shown in Figure 5.

LX10 with Undercut Indicated, Bottom
Click to Enlarge

Figure 5: Pads machined into Thorlabs' devices improve their stability when bolted in place. The pads are highly flat and project above the undercut region, which is highlighted red. The undercut limits the contact area with the table or breadboard.
BA2 with Undercut Indicated, Bottom
Click to Enlarge

Figure 4: This view of the bottom shows the undercut highlighted in red. By removing this material, the pads can be made maximally flat.
BA2 with Undercut Indicated, Top
Click to Enlarge

Figure 3: For optimal stability, the base should be mounted with the undercut facing the optical table or breadboard.

Date of Last Edit: Dec. 9, 2019


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Vacuum-Compatible Ø1/2" Posts

Vacuum Compatibility Specifications
Vacuum Compatibility
as Packageda
>10-6 Torr
Materials 304L Stainless Steel (Post)
316 Stainless Steel (Setscrew)
Preparation and
Packaging
Chemically Cleaned and
Double Vacuum Bagged
Stainless Steel
Outgassing Rate at 20 °C
1.8 x 10-8 Torr-Liters/s/cm2
  • 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.
  • Constructed of 304L and 316 Stainless Steel for Vacuum Applications
  • One 8-32 (M4) Tapped Hole on Top and One 1/4"-20 (M6) Tapped Hole at Base
  • Removable 8-32 (M4) Threaded Setscrew
  • Available in Lengths Ranging from 3/4" to 3" (20 mm to 75 mm)
  • We Also Offer a Complete Line of Standard Ø1/2" Posts

These nonmagnetic, vacuum-compatible stainless steel posts are precision ground to Ø1/2" (Ø12.7 mm). One end has a 1/4"-20 (M6) tapped hole, while the other end has a removable, 8-32 (M4) threaded setscrew (5/64" [2 mm] hex). A side-located Ø0.13" (Ø3.1 mm) hole is bored straight through the post; a balldriver can be inserted through the hole to provide extra leverage when tightening mounted components. This hole also serves to vent the 8-32 (M4) threaded hole. The 1/4"-20 (M6) hole in the bottom of the post is not vented, so we recommend using a vented cap screw.

Based on your currency / country selection, your order will ship from Newton, New Jersey  
+1 Qty Docs Part Number - Imperial Price Available
TR075V Support Documentation
TR075VØ1/2" Vacuum-Compatible Optical Post, 8-32 Setscrew, 1/4"-20 Tap, L = 0.75"
$11.87
Today
TR1V Support Documentation
TR1VØ1/2" Vacuum-Compatible Optical Post, 8-32 Setscrew, 1/4"-20 Tap, L = 1"
$12.54
Today
TR1.5V Support Documentation
TR1.5VØ1/2" Vacuum-Compatible Optical Post, 8-32 Setscrew, 1/4"-20 Tap, L = 1.5"
$14.81
Today
TR2V Support Documentation
TR2VØ1/2" Vacuum-Compatible Optical Post, 8-32 Setscrew, 1/4"-20 Tap, L = 2"
$15.16
Today
TR3V Support Documentation
TR3VØ1/2" Vacuum-Compatible Optical Post, 8-32 Setscrew, 1/4"-20 Tap, L = 3"
$15.75
3 weeks
+1 Qty Docs Part Number - Metric Price Available
TR20V/M Support Documentation
TR20V/MØ12.7 mm Vacuum-Compatible Optical Post, M4 Setscrew, M6 Tap, L = 20 mm
$11.87
Today
TR30V/M Support Documentation
TR30V/MØ12.7 mm Vacuum-Compatible Optical Post, M4 Setscrew, M6 Tap, L = 30 mm
$12.54
3 weeks
TR40V/M Support Documentation
TR40V/MØ12.7 mm Vacuum-Compatible Optical Post, M4 Setscrew, M6 Tap, L = 40 mm
$14.81
Today
TR50V/M Support Documentation
TR50V/MØ12.7 mm Vacuum-Compatible Optical Post, M4 Setscrew, M6 Tap, L = 50 mm
$15.16
3 weeks
TR75V/M Support Documentation
TR75V/MØ12.7 mm Vacuum-Compatible Optical Post, M4 Setscrew, M6 Tap, L = 75 mm
$15.75
Today

Vacuum-Compatible Bases

Item # BA1SV(/M) BA1V(/M) BA2V(/M)
Image
(Click to Enlarge)
BA1SV BA1V BA2V
Slots 1 2 2
Slot Type Straight Straight Straight
Slot Length 1.10" (27.9 mm) 0.81" (20.1 mm) 1.25" (31.8 mm)
Mounting Holes 1 1 3
Dimensions (W x L x H) 1" x 2.3" x 3/8"
(25 mm x 58 mm x 10 mm)
1" x 3" x 3/8"
(25 mm x 75 mm x 10 mm)
2" x 3" x 3/8"
(50 mm x 75 mm x 10 mm)
Vacuum Compatibility >10-6 Torra
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 directly out of the packaging with no additional processing. They can be used at even lower pressures with additional cleaning and processing.
  • Mount Ø1/2" Post Holders and Other Components to an Optical Table or Breadboard
  • Vacuum-Compatible Design (>10-6 Torr)
  • Double Vacuum Bagged for Cleanroom Environments
  • Same Stability and Footprint as Our Standard Mounting Bases

These vacuum-compatible bases are similar to our standard mounting bases, which allow post holders to be secured to an optical table in a variety of position. A 3/8" (10 mm) long 1/4"-20 (M6) vented cap screw (SH25S038V for imperial or SH6MS10V for metric) is recommended for attaching post holders to our mounting bases.

Based on your currency / country selection, your order will ship from Newton, New Jersey  
+1 Qty Docs Part Number - Imperial Price Available
BA1SV Support Documentation
BA1SVMounting Base, 1" x 2.3" x 3/8", Vacuum Compatible
$14.55
Lead Time
BA1V Support Documentation
BA1VMounting Base, 1" x 3" x 3/8", Vacuum Compatible
$14.55
Lead Time
BA2V Support Documentation
BA2VMounting Base, 2" x 3" x 3/8", Vacuum Compatible
$20.50
Today
+1 Qty Docs Part Number - Metric Price Available
BA1SV/M Support Documentation
BA1SV/MMounting Base, 25 mm x 58 mm x 10 mm, Vacuum Compatible
$14.55
Lead Time
BA1V/M Support Documentation
BA1V/MMounting Base, 25 mm x 75 mm x 10 mm, Vacuum Compatible
$14.55
3 weeks
BA2V/M Support Documentation
BA2V/MMounting Base, 50 mm x 75 mm x 10 mm, Vacuum Compatible
$20.50
Today

Vacuum-Compatible Thumbscrews

Specifications
Vacuum Compatibility
as Packageda
>10-6 Torr
Materials 2024-T3 Aluminum
Preparation and
Packaging
Chemically Cleaned and
Double Vacuum Bagged
Aluminum Outgassing
Rate at 20 °C
7.6 x 10-9 Torr-Liters/s/cm2
Maximum Torque 28 in·lbs (3.2 N·m)
  • 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.

The TS25HV and TS6HV/M are 1/4"-20 or M6 x 1.0-threaded for compatibility with our imperial or metric Vacuum-Compatible Ø1/2" Post Holders, respectively. Please note that we do not recommend using an L wrench hex key to tighten these thumbscrews, as this may break off the screw head. The recommended maximum torque is 28 in·lbs (3.2 N·m). We also offer standard spring-loaded thumbscrews.

TS25HV Mechanical Drawing
TS25HV Drawing
Based on your currency / country selection, your order will ship from Newton, New Jersey  
+1 Qty Docs Part Number - Imperial Price Available
TS25HV Support Documentation
TS25HV3/16" Hex-Locking Thumbscrew, 1/4"-20 Thread, Vacuum Compatible
$14.56
Today
+1 Qty Docs Part Number - Metric Price Available
TS6HV/M Support Documentation
TS6HV/M5 mm Hex-Locking Thumbscrew, M6 x 1.0 Thread, Vacuum Compatible
$14.56
Lead Time