Thread to Dowel Pin Adapters


  • Thread into 8-32, 1/4"-20, M4 x 0.7, or M6 x 1.0 Tapped Optomechanical Components
  • Dowel Pin Registers in Tapped Hole of Mounting Surface
  • Allows Free Rotation of Component About Tapped Hole

PTDA25E-P5

External 1/4"-20 Threads,
Ø0.193" Dowel Pin Fits 1/4"-20 Tapped Holes

PTDA4M-P5

External M4 x 0.7 Threads,
Ø4.83 mm Dowel Pin Fits M6 x 1.0 Tapped Holes

Application Idea

Center a mirror directly over a hole in an optical table with the KM100CP mirror mount, see the Application tab for more details.

Related Items


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Click to Enlarge

Item # PTDA8E-P5 used to temporarily position an IDA20-P5 iris mounted on an RS2.5P8E pedestal post.

Item # Thread
(External)
Dowel Pin
Imperial Thread Adapters
PTDA8E-P5 8-32 Ø0.193"a
PTDA25E-P5 1/4"-20
Metric Thread Adapters
PTDA4M-P5 M4 x 0.7 Ø4.83 mmb
PTDA6M-P5 M6 x 1.0
  • The dowel pin diameter is smaller than the internal minor diameter of 1/4"-20 tapped holes.
  • The dowel pin diameter is smaller than the internal minor diameter of M6 x 1.0 tapped holes.

Features

  • Thread into 8-32, 1/4"-20, M4 x 0.7, or M6 x 1.0 Tapped Optomechanical Components
  • Index into 1/4"-20 or M6 x 1.0 Holes of Mounting Surfaces like Stages, Optical Tables, or Breadboards
  • Provides Easy Alignment of Components to Tapped Holes with Free Rotation
  • Allows for Repeatable Insertion of Temporary Components Into the Optical Path
  • Sold in Packages of 5

Thorlabs' Thread to Dowel Pin Adapters are used to align an optomechanical component directly over a 1/4"-20 (M6 x 1.0) tapped hole, such as those on translation stages, optical tables, or breadboards. For quick and easy alignment, thread the adapter into a compatible post (for example a Ø1" pillar or Ø1" pedestal post)a, and then slot the dowel pin into a 1/4"-20 (M6 x 1.0) tapped hole on the mounting surface. The dowel pin allows free rotation about a post's axis while maintaining alignment over the hole. See the Application tab for more details.

Since these adapters index into tapped holes, temporary components like irises or other alignment tools can be quickly inserted into a beam path. We recommend securing the post or post holder to the table or breadboard with additional hardware, like a clamping fork, for permanent installation once the desired rotational position is achieved.

These adapters feature a 5/64" (2.0 mm) hex in the dowel pin for installation and removal. To aid with identification, metric adapters feature an engraved ring around the dowel pin. An O-Ring is included on the 1/4"-20 and M6 x 1.0 externally-threaded adapters to prevent movement from play between threads and to prevent the adapter from becoming over-inserted in the component.

  • These adapters require sufficiently deep threaded holes to fully seat into and therefore are not compatible with Item #s TR075, TRP057, TRP20/M, and TRP14/M which have mounting holes that are too shallow.
Centered example setupClick to Enlarge
View Imperial Product List
Item #QtyDescription
PTDA8E-P51Adapter with External 8-32 Threads to Ø0.193" Dowel Pin, 5 Pack
RS1.5P8E1Ø1" Pedestal Pillar Post, 8-32 Taps, L = 1.5"
CF125C1Clamping Fork for Ø1.25" Pedestal Bases, 1.24" Counterbored Slot, 1/4"-20 Captive Screw
ss8s02518-32 Stainless Steel Setscrew, 1/4" Long, 50 Pack
KM100CP1Kinematic Mirror Mount for Ø1" Optics with Post-Centered Front Plate, 8-32 Taps
PF10-03-m031Ø1" (25.4 mm) Unprotected Gold Mirror
View Metric Product List
Item #QtyDescription
PTDA4M-P51Adapter with External M4 Threads to Ø4.83 mm Dowel Pin, 5 Pack
RS1.5P4M1Ø25.0 mm Pedestal Pillar Post, M4 Taps, L = 38 mm
CF125C/M1Clamping Fork for Ø1.25" Pedestal Bases, 31.5 mm Counterbored Slot, M6 x 1.0 Captive Screw
SS4MS121M4 x 0.7 Stainless Steel Setscrew, 12 mm Long, 50 Pack
KM100CP/M1Kinematic Mirror Mount for Ø1" Optics with Post-Centered Front Plate, M4 Taps
PF10-03-M031Ø1" (25.4 mm) Unprotected Gold Mirror
Item # Qty Description
SWB 1 Articulated Mounting Base, 1/4"-20 Threaded Stud, Qty. 1
CF125 1 Clamping Fork, 1.24" Counterbored Slot, Universal
MB6 1 Aluminum Breadboard 6" x 6" x 1/2", 1/4"-20 Taps
LVL01 1 1.25" Circular Bullseye Level
BMF4 1 Breadboard Mounting Feet (Imperial), Set of 4
Step 4: Clamp Down to Table

Click to Enlarge

Step 3: Rotate to Desired Position

Click to Enlarge

Step 2: Insert Dowel Pin Into Tapped Hole in Optical Table
Click to Enlarge
Step 1. Fasten Adapter to Post

Application Idea

Thread to dowel pin adapters can be used to center a mirror directly over a tapped mounting hole in four steps. In the example shown here, we are centering the KM100CP mirror mount and RS1.5P8E pedestal pillar post over a 1/4"-20 tapped hole in an optical table using a PTDA8E-P5 adapter.

  1. Fasten the adapter to the pedestal post using a 5/64" (2.0 mm) hex key.
  2. Slot the dowel end directly into the 1/4"-20 hole in an optical table
  3. Attach the mirror mount to the pedestal post and rotate into position. The thread to dowel adapter keeps the post centered over the hole during rotation while maintaining a fixed height.
  4. Clamp down the pedestal post with a CF125C clamping fork to lock rotation and immobilize the setup.

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Thread to Dowel Pin Adapters

Based on your currency / country selection, your order will ship from Newton, New Jersey  
+1 Qty Docs Part Number - Imperial Price Available
PTDA8E-P5 Support Documentation
PTDA8E-P5Adapter with External 8-32 Threads to Ø0.193" Dowel Pin, 5 Pack
$26.20
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PTDA25E-P5 Support Documentation
PTDA25E-P5Adapter with External 1/4"-20 Threads to Ø0.193" Dowel Pin, 5 Pack
$26.20
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+1 Qty Docs Part Number - Metric Price Available
PTDA4M-P5 Support Documentation
PTDA4M-P5Adapter with External M4 Threads to Ø4.83 mm Dowel Pin, 5 Pack
$26.20
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PTDA6M-P5 Support Documentation
PTDA6M-P5Adapter with External M6 Threads to Ø4.83 mm Dowel Pin, 5 Pack
$26.20
Today