- Adjuster Lengths Between 0.5" and 2"
- 0.01" Travel per Revolution
- Adjustment Knobs and Threaded Bushings Also Available
3/4" Long Hex Adjuster
1 1/2" Long Hex Adjuster
5/64" (2.0 mm)
Ø3/8" Barrel Adapter
Ø0.58" Removable Adjuster Knob
Ø0.925" Removable Adjuster Knob
Differential Adjuster Screw
|Selection Guide for Adjustment Screws|
|1/4"-100 Matched Adjuster/Bushing Pair|
|1/4"-170 Matched Adjuster/Bushing Pair|
|M2 x 0.20|
|M2.5 × 0.20|
|M3 × 0.20|
|M3 × 0.25|
|M4 x 0.25|
|M6 × 0.25|
|Differential Adjuster Screws|
- 100 TPI Fine Adjustment
- Hex Adjusters Feature a 5/64" (2.0 mm) Hex Socket
- Differential Adjuster with 25 µm/rev Fine Adjustment Over ≥400 µm of Travel
- Removable Adjustment Knobs Allow for Adjustment without Hex Key
- Threaded Bushings, Lock Nuts, and Locking Collar for Adjuster Integration
- Barrel Adapters for Integration with Linear Translation Stages
Thorlabs offers 1/4"-100 hex adjusters 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. Also available is a differential adjuster screw that provides 25 µm/rev of fine adjustment over ≥400 µm of travel. A variety of 1/4"-100 threaded bushings, lock nuts, locking collars and barrel adapters are available to simplify the integration of fine adjusters in your application. Each adjuster comes 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.
Integrating Fine Adjustment Screws Into Optomechanical Systems
The assembly process begins by producing the appropriately sized mating hole for the threaded bushing. The recommended bore diamaters can be found with the product information for each bushing sold below. Given the close fit between the threaded bushing and the mating adjuster screw, we caution against using a press fit to assemble these products. For our own production needs, we use a permanent anaerobic adhesive that provides excellent long-term performance. Locking bushings with nuts do not require adhesive as they are held in place by the locking nut.
We recommend using Loctite Anaerobic Adhesive product number 680 or equivalent. In order to ensure maximum strength between the bonded parts, we strongly urge the user to follow carefully the instructions provided by Loctite, which specify the amount of clearance between the threaded bushing and the mounting plate. The most common source of failure is not allowing for the proper clearance between the parts being bonded since this clearance provides for the proper volume of adhesive.
When assembling, apply a small amount of the Loctite adhesive to the threaded bushing only. Rotate the bushing as it is installed to ensure a uniform distribution of the adhesive. After insertion, remove any excess adhesive from around the part.
As shown in the figure to the right, the flange on the mating bushing is designed to support the axial load of the screw and bushing assembly.
OEM & Custom Precision Screws
Thorlabs manufactures custom and high volume OEM precision screws and bushings with various diameters, lengths, and threads. To inquire about custom or OEM precision screws, please contact Technical Support or use the "Contact Us" form to the right. A specialist will contact you within 24 hours or the next business day.
Precision Screw Capabilities
Thorlabs' in-house machine shop, located in Newton, NJ, gives us the ability to quickly produce large quantities of precision screws and bushings. We are equipped to manufacture screw diameters ranging from 2 mm to 20 mm with lengths up to 165 mm and a maximum thread pitch of 200 TPI. Our standard adjuster screw design has a hardened steel ball tip to provide a single point of contact; for other applications we are able to provide adjusters without the steel ball. Custom orders can be achieved on a case-by-case basis. For large orders of an item, Thorlabs passes on to the customer the cost savings associated with planned production of high volumes of that item. For more information on Thorlabs' discount pricing policy, click the "V" link to the right. We also offer a large variety of stock precision screws, which are available here.
Fast Turn-Around Times
Our experienced, highly skilled machinists are running our on-site Citizen Swiss Screw Machines 24 hours a day, allowing us to produce high-volume custom and OEM orders. Each machine is capable of running unattended, producing one screw every 30 to 120 seconds. This flexibility allows us to fulfill multiple orders at once without sacrificing quality.
Thorlabs inspects all of our fabricated precision screws and bushings after the initial fabrication process and right before packaging. All inspections adhere to the ANSI AQL1.5 acceptable quality level, which states that if a certain percentage, based upon the amount of product in a certain lot, does not meet specification, then the entire lot is not sold. This ensures that all customers receive the highest quality product every time and that all items will be of equal performance.
Precision Screw Production
- Five Lengths Available from 0.5" to 2"
- 5/64" (2 mm) 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" (2 mm) hex key, F25USK1 removable adjustment knob (sold below), or HKTS-5/64 hex key knob (sold below). The F25US series have a maximum load of 15 lbs (6.8 kg). The adjuster body is constructed of 303 stainless steel and comes pregreased to ensure smooth mating into compatible components. The ball tip is constructed using 440 stainless steel that is fixed onto the adjuster using epoxy.
Click to Enlarge
Coarse Thread Length and Adjuster Length (L)
Click for Details
A Cross-Section of a Differential Adjuster Screw,
Showing the Internal Components
- 1.02" (26.0 mm) Adjuster Length (L)
- Coarse Thread Length: 0.76" (19.3 mm)
- Fine Adjustment: 25 µm/rev Over ≥400 µm of Travel
- Ø0.49" (12.4 mm), 0.15" (3.8 mm) Thick Locking Ring
- On-Axis Load Capacity: 11.25 lbs (5.1 kg)
- Recommended Preload: 1 to 2 lbs (0.5 to 1 kg)
Thorlabs' DAS25U Differential Adjuster Screw comes pre-greased to ensure smooth mating into compatible components. To install the adjuster, screw the threads into the bushing by hand. Ensure that cross threading does not occur in order to avoid damage to the adjuster and bushing. Additionally, the screw includes a Ø0.49" (Ø12.4 mm), 0.15" (3.8 mm) thick locking ring with a knurled surface for improved grip. Four Ø0.09" (Ø2.3 mm) blind holes in the ring allow a hex key to be inserted to assist with tightening.
When used with a compatible component, coarse adjustment is provided by the external threads on the main screw body, labeled B on the diagram to the lower right. The screw can be actuated using the attached knob, labeled A, or the 5/64" (2 mm) hex socket. The knob can also be removed if needed due to space constraints.
The fine-adjustment mechanism provides a highly de-magnified displacement of 25 µm per revolution and can be actuated using a 1/16" hex accessible through the center of the 5/64" (2 mm) hex for coarse adjustment.
As illustrated in the diagram to the right, an intermediate actuator, labeled C, is threaded into the main body screw (B) and onto a push rod (D) that terminates with a ball tip. A pin on the push rod fits into a slot on the main body screw and prevents these two components from rotating relative to each other. As a result, when the intermediate actuator is rotated, it will be translated along the main body screw at a rate determined by the intermediate actuator's external thread pitch while the push rod is translated in the opposite direction at a rate determined by the intermediate actuator's internal thread pitch. Thus, differential movement is achieved between the intermediate actuator and the push rod.
The DAS25U differential adjuster screw has an intermediate actuator with an external thread pitch of 400 µm and an internal thread pitch of 375 µm. When the intermediate actuator is rotated clockwise, it advances in the main body by 400 µm per revolution. At the same time, the push rod, which is restricted from rotating by the main body, retreats by 375 µm per revolution, providing a total displacement of 25 µm per revolution.
- Ideal for Slip Fit
- Two Lengths Available
- Material: 510 Phosphor Bronze (Vacuum Rated for 10-6 Torr)
- Recommended Bore Diameter: 0.3395" +0.0005"/-0.0000"
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 0.3395" +0.0005"/-0.0000". To learn more about the use of fine adjustment screws and bushings in optomechanical systems, please see the Integration tab above.
- Material: 510 Phosphor Bronze (Vacuum Rated for 10-6 Torr)
- Adapts 1/4"-100 Adjusters to Ø3/8" Barrel Size
- Recommended Bore Diameter: 0.375" +0.002"/-0.000"
These 1/4"-100 threaded to Ø3/8" barrel adapters are made from 510 Phosphor Bronze (vacuum rated for 10-6 torr). They allow our 1/4"-100 adjusters to be used with linear translation stages that accept actuators with Ø3/8" (Ø9.5 mm) barrels. The photo to the right shows an adjuster screw used as a replacement for the actuator included with the translation stage. For vacuum applications, we recommend a thorough ultrasonic cleaning to remove any grease or particulates prior to use.
- 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.
- Lock Nut 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 nut can be used with any 1/4"-100 adjuster for long-term stability and features a 13 mm hex. This lock nut is compatible with Polaris mounts that have 1/4"-100 adjusters, excluding the piezo-driven mounts, mounts with low-profile adjusters (Item #s POLARIS-K1-H and POLARIS-K1-2AH), and vertically driven mounts (Item #s POLARIS-K1VS2 and POLARIS-K1VS2L). The adjuster can be held in place with an adjuster thumbscrew or hex key while lightly tightening the lock nut by hand or with a 13 mm thin-head wrench or cone wrench.
For applications that require frequent tuning of the adjusters, the lock nuts only need to be lightly tightened by hand to a torque of approximately 4 to 8 oz-in (0.03 to 0.06 N·m). For long term stability, we recommend tightening to a torque of 32 oz-in, which can be achieved by using our TW13 preset torque wrench. To avoid cross threading the lock nut, place it against the adjuster and "unscrew" the lock nut until you feel a slight drop; then thread the lock nut onto the adjuster.
Cleanroom and Vacuum Compatibility
This lock nut is compatible with cleanroom and vacuum applications. The lock nut is chemically cleaned using the Carpenter AAA passivation method to remove sulfur, iron, and contaminants from the surface. After passivation, it is double vacuum bagged to eliminate contamination when transported into a cleanroom.
- Compact Locking Collar: Ø0.33" (Ø8.4 mm), 0.08" (1.9 mm) Thick
- Use One Collar To Lock an Adjuster to a Bushing
- Use Two Collars to Create a Hard Stop on an Adjuster
- Install and Remove with the POLARIS-T2 Spanner Wrench
The POLARIS-LNS1 locking collar is a compact alternative to the lock nut sold above. This locking collar is compatible with all of the 1/4"-100 adjusters sold on this page, as well as those used in many of our mirror mounts and stages. This locking collar is compatible with Polaris mounts that have 1/4"-100 adjusters, excluding the piezo-driven mounts and mounts with low-profile adjusters (Item #s POLARIS-K1-H and POLARIS-K1-2AH). Each collar is only 0.08" (1.9 mm) thick and constructed of stainless steel. We recommend the POLARIS-T2 Spanner Wrench to install or remove these locking collars. A center through hole allows a 2 mm ball driver to pass through the spanner wrench, so that the adjuster can be held in position while the locking collar is engaged.
The locking collar can be used to lock an adjuster in a desired position or to create a hard stop at any position to prevent overdriving an adjuster. For applications that require frequent tuning of the adjusters, the locking collar only needs to be lightly tightened to a torque of approximately 4 to 8 oz-in (0.03 to 0.06 N·m). For long term stability, we recommend tightening to a torque of 32 oz-in, which can be achieved by using our TW13 preset torque wrench in combination with the POLARIS-T2 wrench. To avoid cross threading the locking collar, place it against the adjuster and "unscrew" the collar until you feel a slight drop; then thread the collar onto the adjuster.
Cleanroom and Vacuum Compatibility
This locking collar is compatible with cleanroom and vacuum applications. The locking collar is chemically cleaned using the Carpenter AAA passivation method to remove sulfur, iron, and contaminants from the surface. After passivation, it is double vacuum bagged to eliminate contamination when transported into a cleanroom.
Click to Enlarge
F25USK1 and F25USK2 Knobs Shown Attached to a POLARIS-K1 Mirror Mount
|Item #||Knob Diameter|
- 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.
Please note that these knobs are not compatible with Polaris mounts that use side-hole adjusters. The recessed bore of knob is not deep enough to allow the knob to engage the threads on the side-hole adjuster.
- 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" Hex Key Adjuster Thumbscrews allow for quick adjustment of many 5/64" and 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.