Differential Adjuster Screw

Features

• Length of Screw: 1" (25 mm)
• Coarse Thread: 1/4"-80
• Fine Adjustment: 25 µm/rev Over ≥400 µm of Travel
• On-Axis Load Capacity: 11.25 lbs (5.1 kg)
• Recommended Preload: 1 to 2 lbs (0.5 to 1 kg)

The DAS110 is ideal as a drop-in replacement for the standard 1/4"-80 adjusters used on most Thorlabs' Kinematic Mirror Mounts and comes pregreased 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.

Coarse Adjustment
The knob A is fastened to the 1/4"-80 externally threaded Main Body B, as shown in the drawing above. This mechanism provides the coarse angular adjustment of the kinematic mount. Alternatively, knob "A" may be removed to expose a 5/64" hex socket which may also be used for coarse angular adjustment.

Fine Adjustment
The fine-adjustment (25 µm/rev) is actuated by inserting a 1/16" hex wrench through the clearance hole in the adjuster knob, or into the smaller hex socket if knob A is removed. For details on this hex mechanism, click on the mechanical drawing above for a detailed view. Each rotation of the DAS110 fine-adjustment mechanism yields a highly de-magnified displacement of just 25 µm.

The Main Body B is also internally threaded with an M3 x 0.40 thread, this thread holds the intermediate actuator C, which may be rotated by a hex wrench. The key to the design is that the intermediate actuator is both internally and externally threaded allowing a differential movement to be achieved between the intermediate actuator C and the Push Rod D, as shown in the drawing above.

The external thread of the intermediate actuator is the same M3 x 0.40 mm thread internal to the main body. When the intermediate actuator is rotated clockwise, it moves out of the main body by 400 µm per revolution. Connected to the internal thread of the intermediate actuator is the push rod; the push rod mates to the intermediate actuator via a M3 x 0.375 thread and is restricted from rotating by the main body. Now as the intermediate actuator is rotated, it advances at the rate of 400 µm/rev, but the push rod retreats at 375 µm/rev. This results in a differential motion of the push rod that is equal to the net difference of the pitch of the two threads for total displacement of 25 µm/rev.

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.

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 2.5 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.

Click to Enlarge

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.

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