Hex Adjusters, 6-80 Fine (2023)

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


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

These Fine Hex Adjuster Screws are great for miniature mounts. Manufactured to exact tolerances to ensure a smooth feel and excellent long-term stability, Thorlabs has developed a set of specifications that meet industry class 3 standards. All of our fine hex adjuster screws are made to these extremely tight tolerances and come lubricated to ensure smooth mating into compatible components. Each screw is individually tested with a master gauge set that ensures the interchangeability of our adjuster screws and threaded sleeves.

Hex Adjusters, 6-80 Fine (2)

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.

Drilling and Tapping

While we recommend using our fine adjusters with the appropriately matched threaded bushing (sold below), it is also possible to incorporate them directly into a part or material by creating a threaded hole. For the adjusters on this page, the diameter of the pilot bore should be 0.126" ± 0.002". The corresponding imperial drill bit size is 1/8" (0.1250"). The hole can then be tapped with TAP680. For fine pitch threads, it is especially important to tightly tolerance the pilot bore because of the shallow thread depth. For more information, see our taps and drill bit kit page.

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 24hours or the next business day.

Click to Enlarge

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 20mm with lengths up to 165mm 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.

Click to Enlarge

Fast Turn-Around Times
Our experienced, highly skilled machinists are running our on-site Citizen Swiss Screw Machines 24hours 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.

High 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

Posted Comments:

Tim Cole &nbsp(posted 2021-03-29 10:21:51.17)

You should do a review on your adjustment screws in general, I've found a few instances where the solid model provided doesn't match the specs of the drawings or the listing on the website. So far I've seen mismatches in ball tip diameter, total screw length, and hex size.

YLohia &nbsp(posted 2021-04-14 04:24:37.0)

Thank you for your feedback and bringing this to our attention. We will have one of our mechanical engineers go through the relevant parts and make the necessary changes.

Keith Kessler &nbsp(posted 2019-12-04 14:06:50.86)

Hi, How do the knobs attach and get locked in place on the treaded adjuster?

llamb &nbsp(posted 2019-12-05 08:05:16.0)

Thank you for your feedback. The #6-80 thread on the F6SSK1 knob is only 0.2" deep, and the knob has a smaller Ø0.104" hole thru the full length. When threading in a fine adjuster screw, it will bottom out on the knob's smaller internal diameter to lock into place. You can also use threadlocking adhesive on the knob's internal threads if you wish to create a more permanent lock.

franco brioschi &nbsp(posted 2019-10-17 15:28:21.75)

Taking into account the thread of this screw, the only way to lock it is is by means of LN680 nut. Due their small diameter, these nuts are difficult to tighten. It would be really useful if hex locking nuts like those mounted on the POLARIS-K05T2 were available

llamb &nbsp(posted 2019-10-22 10:34:36.0)

Thank you for your feedback! While the LN680 features a knurled outer diameter for better gripping, as well as blind holes to allow a hex key to help tighten the nut, a hex nut shape can certainly provide additional ease for locking. I have added this new product idea into our internal product forum for further review.

dharvey &nbsp(posted 2014-08-26 14:59:38.157)

Hello, we are designing your adjustment screws into our products. Sometimes we cannot use the ball end tip. We need to replace it with an insulating plastic tip.Can you buy the adjustment screws without the stainless steel ball?How do you remove the stainless steel ball?

cdaly &nbsp(posted 2014-08-27 09:49:11.0)

Response from Chris at Thorlabs: The ball is glued in place, so it'd likely be very difficult to remove once in place, but we can offer a custom version without the ball if you'd like. I will contact you directly to discuss this.

bdada &nbsp(posted 2012-04-25 09:46:00.0)

Response from Buki at Thorlabs to hadmack:Thank you for using our feedback tool. The recommended bore diameter for our 6-80 bushings is 0.225" +0.001/-0.000.

hadmack &nbsp(posted 2012-04-20 17:01:22.0)

What is the recommended bore diameter for the bushings?

jens &nbsp(posted 2009-12-17 18:28:08.0)

A reply from Jens at Thorlabs: thank you for the notification. We are currently going through the complete page to make sure this is corrected.

user&nbsp(posted 2009-12-17 16:25:51.0)

Misspelling of Exceeds

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