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Click for POLARIS-CA1/M Holding Torque Results*
The Polaris clamping fork design has undergone extensive testing to ensure high-quality performance. See the full presentation for more details.

*It is important to note that the 1/4"-20 and M6 x 1.0 clamping torque values have been adjusted to provide the same clamping post and table forces. Also note that the maximum recommended tightening torque for an 18-8 stainless steel screw is 75.2 in-lbs for a 1/4"-20 screw and 8.8 N-m for an M6 x 1.0 screw. Higher mounting torques can cause the screw to fail.

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The arm can be mounted with either flat surface in contact with the table, allowing for compact setups.

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Side-Located 1/4"-20 (M6) Screw Actuates Clamping Bore

• 3-Point Contact Bore with Flexure Clamping Mechanism
  • Versions for Ø1" or Ø25 mm Posts for Polaris Mounts and Ø1" Monolithic Polaris Mount (See Table Below)
  • 0.60" Bore Depth Supports Height Adjustments Up to 0.25"
  • Allows Posts to be Rotated 360°
• 0.75" (19.1 mm) or 1.30" (33.0 mm) Slot for 1/4"-20 (M6) Cap Screw
• Heat-Treated, Stress-Relieved Stainless Steel Provides Large Clamping Force
• Design Supports Left- and Right-Handed Orientations (See Lower Left Image)
• High Stability Ideal for Use with Our Kinematic Polaris Mirror Mounts
• Vacuum Compatible to 10^-9 Torr at 25 °C with Proper Bake Out
• ±0.001" (±0.02 mm) Surface Flatness

The Polaris^® Clamping Arms are the ideal solution for stably mounting our Ø1" or Ø25 mm Posts for Polaris Mounts or Ø1" Monolithic Polaris Mount. Each clamping arm, which is machined from heat-treated, stress-relieved stainless steel bar stock, provides extremely high holding forces with minimal torquing of the mounting screws (see the graph to the right).

The flat, non-bridging top and bottom surfaces of each clamping arm allow it to be used with either side in contact with an optical table or other mounting surface. This feature allows the clamp to be positioned in left- or right-handed orientations and optical components to be placed in near contact to one another while minimizing the footprint (see the image to the left). On each side of the arm, a relief cut around the slot protects the ±0.001" (±0.02 mm) flat surface from any marring due to the screw and washer, allowing for more stable mounting.

The clamping arms are offered with slot lengths of 0.75" (19.1 mm) or 1.30" (33.0 mm), providing flexibility when used in applications such as tight laser cavity setups. Four of our clamping arms are designed to hold Ø1" posts, while the remaining two are designed to hold Ø25 mm posts; see the table below for details. Note the arms with a Ø1" (25.4 mm) bore are not compatible with Ø25 mm posts; the bore diameter is too large and will not contact the post when clamping.

Non-Bridging Design: Industry Standard Clamping Fork
vs. Polaris Clamping Arm

Industry standard clamping forks are designed with a bridge, as shown in Figure 1, for clamping to pedestal-style posts or post holders. This design will slightly damage the laser platform during each use by pulling up the part of the platform located under the bridge. The Polaris clamping arm, as shown in Figure 2, is designed with a flat top and bottom to eliminate this problem.

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Figure 1: A Bridge is Created When an Industry Standard Clamping Fork is Used with a Pedestal Post

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Figure 2: The Polaris Clamping Arm Eliminates the Bridge Created by an Industry Standard Clamping Fork

The flexure clamp, shown in the photo to the left, is actuated using a side-located 1/4"-20 (M6 x 1.0) cap screw and allows a post to be rotated 360° about its center. As the flexure clamp and mounting slot are secured with separate screws, the position of the fork and the rotational alignment of the post can be adjusted independently. While best performance is achieved with full post engagement, the 0.60" (15.2 mm) thick mounting bore supports up to 0.25" of post height adjustment.

The Polaris clamping fork design has undergone extensive testing to ensure high-quality performance; see the graph to the upper right. For optimal performance, we recommend tightening the flexure clamping screw of an imperial clamping arm with 15 to 25 in-lb of torque and the flexure clamping screw of a metric clamping arm with 1.75 to 3 N•m of torque. When mounting to a table or platform, we recommend using 40 to 65 in-lb of torque for an imperial clamping arm and 4.75 to 7 N•m of torque for a metric clamping arm. Please note that the values for imperial and metric clamps are not a direct conversion due to an efficiency difference between 1/4"-20 and M6 x 1.0 screws. The efficiency of M6 x 1.0 screws is about 5% less than that of 1/4"-20 screws due to differences in diameter and pitch. For best results, use the maximum recommended torques from each range. These torque values can be dialed in using a torque driver.

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Deep Base Allows Height Adjustment

• RB2 Base Allows Post Extensions to be Used as a Variable Height Mounting Structure
• Hollow Base Allows Post Extension to Pass Through for 0.5" of Height Adjustability
• Convenient Vertically Accessed Locking Screw

The RB2(/M) pillar post base mounts Ø1" (25 mm) optical posts at a variable height (shown to the right). The hollow base allows the post to pass through, allowing 0.5" of post height adjustment. Translation is locked via a top-located clamping screw.

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• Post Mount with a Ø1" (Ø25 mm) Double Bore and Flexure Clamping Mechanism
• Mounts Ø1" Posts or Ø1/2" Post Holders
• 0.325" (8.3 mm) of Height Adjustment and 360° Coarse Rotational Adjustment
• 8-32 (M4) Tapped Hole for Rotation Hard Stop with the RM1B Ø1" Post Collar

The BA2F Post Mount features a Ø1" (Ø25 mm) double bore and flexure clamping mechanism. This clamp allows for both height and rotational adjustment of either an Ø1" optical post or a Ø1/2" post holder. The clamping mechanism is actuated by a 3/8"-24 (M10 x 1.5) clamping screw with 3/16" (5 mm) hex key. A permanent steel insert* at the end of the flexing mechanism prevents damage to the clamp from overtightening.

An RM1A or RM1B Ø1" post collar can be used with Ø1" posts or Ø1/2" post holders as a hard stop for repeatable height adjustment. The base also features an 8-32 (M4) tapped hole near the double bore; when a cap screw or setscrew is inserted into this hole, the post collar can also function as a rotational stop (see photo on the top right).

Each base has two 1.25" (31.8 mm) long counterbored slots for 1/4"-20 (M6) cap screws for attachment to an optical table or breadboard.

*Since our Ø1/2" post holders are slightly smaller in diameter than our Ø1" posts, the flexure mechanism will contact the steel insert when mounting Ø1/2" post holders. This is normal and will not harm the mounting base.