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Hex Adjusters, M3 x 0.25 Fine
These M3 x 0.25 adjuster screws are ideal for limited space applications that require fine (250 μm/rev) resolution. Each threaded component is individually tested with a master gauge set that ensures the interchangeability of our fine adjustment components. The adjuster body is constructed of 303 stainless steel and the ball tip is constructed using 440 stainless steel that is fixed onto the adjuster using epoxy. The hex adjusters feature a 1.5 mm hex socket, which provides a simple way to make fine adjustments. The fine adjuster screws come lubricated to ensure smooth mating into compatible components.
Integrating Fine Adjustment Screws Into Optomechanical Systems
The assembly process begins by producing the appropriately sized mating hole for the threaded bushing. 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.
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 2.5 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
Precision Screw Production
Our high precision M3 x 0.25 Fine Hex Adjusters can be adjusted with a 1.5 mm hex key or with our F3SSK1 removable adjustment knob. The F3SS series hex adjusters have a maximum load of 18.75 lbs (8.5 kg).
These adjuster screws are designed to be used with M3 x 0.25 threaded bushings, available below. Alternatively, for more compact applications, an M3 x 0.25 plug tap can create M3 x 0.25 tapped holes in optomechanical components.
Our high precision MAS Series M3 x 0.25 adjustment screws are a convenient drop-in alternative to our F3SS series hex adjusters. The non-slip knurled knob improves adjustment sensitivity.
The F3SSK1 and F3SSK1L Removable Adjustment Knobs thread onto our M3 x 0.25 F3SS series hex adjusters to allow adjustment without the use of a hex key. This provides quick and easy adjustments for a broad range of applications. The adjuster knobs are available in two sizes: standard (Ø7.1 mm) and large (Ø14.7 mm).
Our F3SSN1P M3 x 0.25 threaded bushing is commonly used in slip fit applications where fine adjusters are needed. Due to the tolerances of our fine adjusters, we discourage press fitting these bushings. The recommended bore diameter for our M3 x 0.25 bushings is 4.5009 mm +0.0127/-0.0000 mm. Please see the Integration tab for more information. For vacuum applications, we recommend a thorough ultrasonic cleaning to remove any grease or particulates prior to use.
Our N250L3P vacuum-compatible ultra-fine adjuster nut is internally M3 x 0.25 threaded and externally M4.5 x 0.5 threaded. These sleeves can be threaded in to M4.5 x 0.5 tapped holes to provide M3 x 0.25 fine adjustment in a variety of applications where threaded bushings are not suitable. For vacuum applications, we recommend a thorough ultrasonic cleaning to remove any grease or particulates prior to use.
The LN3M25 lock nut features a knurled outside diameter to make gripping the nut easier when loosening or tightening. The 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.