1/4"-100 Adjustment


1/4"-100 Adjustment

  • Adjuster Lengths between 0.5" and 2"
  • 0.01" Travel per Revolution


  • 100 TPI Fine Adjustment
  • Hex Adjusters Feature a 5/64" Hex Socket
  • Removable Adjustment Knobs Allow for Adjustment without Hex Key
  • Threaded Bushings and Lock Nuts for Fine Adjuster Integration

Thorlabs offers 1/4"-100 hex adjuster that exceed class 3 standards. Each screw is individually tested with a master gauge set that ensures the inter-changeability of our adjuster screws and threaded bushings. A variety of 1/4"-100 components are available to simplify the integration of fine adjusters in your application. The fine adjusters come lightly lubricated to ensure smooth mating into compatible components.

We also offer Polaris™ Matched Adjuster/Bushing Pairs, which offer better adjustment stability and a smoother feel for smaller adjustment changes.


1/4"-100 Hex Adjusters

* Five Lengths Available from 0.5" to 2"
* 5/64" Hex Key Compatible
* Max Load: 15 lbs (6.8 kg)

Our high precision 1/4"-100 Fine Hex Adjusters can be adjusted with a 5/64" hex key, F25USK1 removable adjustment knob (sold below), or HKTS-5/64 hex key knob . The F25US series have a maximum load of 15 lbs (6.8 kg)


1/4"-100 Threaded Bushings

* Ideal for Slip Fit
* Two Lengths Available
* Material: 510 Phosphor Bronze (Vacuum Rated for 10-6 Torr)
* Recommended Bore Diameter: 0.340" +0.001/-0.000

Our 1/4"-100 Threaded Bushings are commonly used in slip fit applications where fine adjusters are needed. Due to the tolerances of our fine adjusters, we discourage press fitting this bushings. The recommended bore diameter for our 1/4"-100 bushings is 0.340" +0.001/-0.000.


1/4"-100 Adjuster Lock Nut

* Knurled Outside Diameter for Easy Tightening
* Material: 510 Phosphor Bronze
* Vacuum Compatibility: 10-6 Torr

The LN25100 lock nut features a knurled outside diameter, which helps when tightening or loosening the nut. This lock nut is made from 510 Phosphor Bronze, which is vacuum rated for 10-6 Torr. Each nut features blind holes that allow a hex key to be used to help tighten the lock nut.


1/4"-100 Adjuster Lock Nut, Stainless Steel

  • Lock Nuts Compatible with the 1/4"-100 Adjusters Sold Above
  • Also Compatible with the Adjusters Included on our Polaris Mounts for Ø1" Optics
  • Tighten Using a 13 mm Hex Thin-Head or Cone Wrench
  • 0.08" (1.9 mm) Thick


The POLARIS-LN1 stainless steel lock nuts can be used with any 1/4"-100 adjuster for long-term stability. Lock nuts only need to be lightly tightened to a torque of approximately 4 to 8 oz-in (0.03 to 0.06 N·m). The beam can be held on target with the adjuster thumbscrew or hex key while lightly tightening the lock nut by hand or with a 13 mm thin-head wrench or cone wrench. These lock nuts are compatible with many of our Ø1" Polaris mounts, excluding the POLARIS-K1PZ Piezo-Driven Polaris, the POLARIS-K1-H, and the POLARIS-K1-2AH.


Cleanroom and Vacuum Compatibility
This lock nut is compatible with cleanroom and vacuum applications. The lock nuts are chemically cleaned using the Carpenter AAA passivation method to remove sulfur, iron, and contaminants from the surface. After passivation, they are double vacuum bagged to eliminate contamination when transported into a cleanroom.


1/4"-100 Removable Adjustment Knobs

  • Use with 1/4"-100 Hex Adjusters
  • Clearance Hole Allows Access to Hex Socket
  • Knurled Knob Increases Adjustment Sensitivity
  • Available in 2 Sizes (See Table to the Right)


These removable adjustment knobs are compatible with our 1/4"-100 adjusters, including those used in the Ø1" Polaris Kinematic Mounts. These knobs enable quick and easy tweaking of an actuator without needing a hex key.


We offer two sizes of adjustment knobs. The Ø0.58" standard size (F25USK1) is similar in size to the stainless steel knobs included with our Polaris mount, while the larger Ø0.925" size (F25USK2) provides additional angular resolution.

Item #Knob Diameter
F25USK1 0.58"
F25USK2 0.925"


5/64" and 2 mm Hex Key Adjusters

  • For Convenient Adjustment of 5/64" and 2 mm Hex-Driven Actuators
  • Red Anodized Adjustment Knob with Engraved Hex Size
  • Replaceable Hex Tip
  • Sold in Packages of 4

These 5/64" and 2 mm Hex Key Adjuster Thumbscrews allow for quick adjustment of many 5/64" (2 mm) hex-driven actuators (or standard actuators with the knobs removed). These temporary knobs can be left in the screw's hex socket between adjustments for convenience (see photo to the right). An 8-32 setscrew (5/64" hex) secures the replaceable hex bit, which can be reversed if the tip is stripped. Contact Tech Support to order replacement hex key bits.

We offer hex key thumbscrews in sizes from 0.050" to 3/16" and 2 mm to 5 mm.



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

contact us

Tel               +966 35823441
Fax               +966 35823441
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