Post Holder Bases
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Post Holder With Lens Mounted on BA1L Base
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The height of any component mounted on a BA2(/M) base can be increased in increments from 0.010" (0.25 mm) to 2" (50 mm) using a Mounting Base Spacer. Here a BA2 base is shown with a BA2S7 1" Mounting Spacer.
Thorlabs offers a variety of standard anodized aluminum bases to best utilize space on an optical breadboard. For close positioning of components, our BA1S(/M) base features the smallest footprint. For increased stability while maintaining a small footprint, the two-slotted BA1(/M) is a good option. For the greatest stability, consider either our BA2(/M) or BA3(/M) base, each of which is twice the width of our BA1(/M) base. The BA2(/M) features two straight slots, while the BA3(/M) has two radial slots for ±45° of manual rotation. As our longest standard base, the BA1L(/M) provides 1.44" (36.6 mm) of lateral positioning and can be secured to an optical breadboard by two screws, even when oriented at varying angles with respect to the tapped hole pattern (see photo to the right).
Please note that a 3/8" long 1/4"-20 (10 mm long M6) cap screw is recommended for attaching post holders to our standard mounting bases.
To reduce packaging waste, we offer our most popular sizes in packs of five.
These vacuum-compatible bases are constructed from 6061-T6 aluminum and are chemically cleaned and prepared for vacuum applications before packaging. They are compatible directly out of the packaging with vacuum environments down to 10-6 Torr. With additional cleaning and processing, they can be used at even lower pressures, only limited by the outgassing rate of the aluminum, which is 7.6 x 10-9 Torr-Liters/s/cm2 at 20 °C. The material properties of the 6061-T6 aluminum and the cleaning methods that are completed by the end user should be used to determine the appropriateness of these products and materials in a specific vacuum system operating at pressures under 10-6 Torr.
These bases are packaged in double airtight bags for cleanroom and vacuum chamber applications. A 3/8" (10 mm) long 1/4"-20 (M6) vented cap screw (SH25S038V or SH6MS10V, respectively) is recommended for attaching post holders to our mounting bases. We also offer additional vacuum-compatible Ø1/2" post system components.
These anodized aluminum magnetic bases are modeled after our popular standard bases but are enhanced by bottom-mounted rare earth magnets, which provide the ability to temporarily secure components during the setup process. The force from these magnets is strong enough to help prevent accidental movement of components, while still allowing for easy repositioning. The full functionality of these bases can only be achieved when using them on a magnetic table or breadboard; however, they can function as a standard base on non-magnetic surfaces as well.
Each base attaches to a post holder via cap screws that fit within a bottom-located 1/4" (M6) counterbored hole. For final attachment to an optical breadboard, each base features at least one slot for a 1/4"-20 (M6) cap screw. Once positioning is complete, these bases must be screwed down to be permanently secured to the table. The BA1SR provides one 1.10" (27.9 mm) slot and allows for the smallest footprint. For increased stability while maintaining a small footprint, the BA1R provides two 0.81" (20.1 mm) slots. Finally, for the most support, the BA2R features two 1.25" (31.8 mm) slots. In addition, the BA2R comes with four bottom-located M3 counterbored holes for 34 mm rail mounting.
The anodized aluminum BA2T2(/M) complements our popular line of standard mounting bases. It features a 1" (25.4 mm) long, counterbored slot along the center length that contains a 1/4"-20 (M6) threaded stud ideal for use with our Ø1/2" post holders. This slot provides for two-dimensional positioning of any attached optical component. To reposition a post holder on the base, loosen it by rotating it counter-clockwise, slide it into the desired position, and retighten it to the base. The base also contains two 1/4"-20 (M6) counterbored holes located on either side of the 1" long slot.
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Centrally Located Slot Allows Mounting of Components Outside of the Standard 1" Hole Pattern
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The UBP2(/M) Universal Base Plate increases the flexibility of any optical setup by providing mounting holes in virtually any orientation on an optical table or breadboard. This freedom allows users to mount various components or stages in a wide array of orientations outside of what is dictated by the standard 1" (25 mm) hole pattern. The counterbores in the plate also allow one to adapt metric components to an imperial optical table and vice versa.
The plate dimensions are 2.5" x 2.5" x 3/8" or 65 mm x 65 mm x 10 mm for the metric version. The 1.25" (31.8 mm) long counterbored slot for 1/4" (M6) cap screws is centrally located and allows 360° rotation of the plate as well as rough translation on the optical table. An array of 1/4"-20 (M6) and 8-32 (M4) tapped mounting holes are available for mounting components in various orientations, while four 4-40 tapped holes are spaced for compatibility with our 30 mm cage system. Two Counterbored holes for both 1/4" (M6) and #8 (M4) cap screws are also located on both sides of the base plate for mounting optical post assemblies.
The counterbored holes for 1/4" (M6) cap screws are located in two corners on each side of the plate and are diagonally across from one another. The counterbored holes for #8 (M4) cap screws are located on the center line perpendicular to the counterbored slot with a spacing of 2" (50 mm) on the top of the plate and 1" (25 mm) on the bottom of the plate. Please see the mechanical drawing above for more details.
Please note that these plates are not machined with relief cuts like the other plates shown on this page.
The BA2F(/M) Flexure Mounting Base features a Ø1" (Ø25 mm) double bore and flexure clamping mechanism. This clamp allows for both height and rotational adjustment of both Ø1/2" post holders and Ø1" optical posts. It 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. With a cap screw or setscrew inserted into this hole, the post collar can also function as a rotational stop (see photo on the top right).
Note: The flexure mechanism will contact the steel insert when mounting Ø1/2" post holders, since they are slightly smaller in diameter than Ø1" posts. This is normal operation and will not harm the mounting base.
Our 360° swivel base adapter fits standard Ø1/2" post holders with 1/4"-20 (M6) mounting holes and minimizes the amount of time it takes to assemble an optical system. In addition, the swivel design is ideal for applications that require a large number of components to be packed into a small area. When our Ø1/2" post holders are used with this adapter, the combination is nearly that of our very popular Universal Post Holders. This anodized aluminum adapter has the benefit of compatibility with any of our existing Ø1/2" post holders but does not offer the same height flexibility of the swiveling post holders, which allow the post to be lowered all the way to the table.
Thorlabs' RSPC Position Retainer is used to realign bases, and other squared-off components, that have been removed from an optical system. It acts as a marker on the breadboard or optical table in the event that you need to remove a component from your set-up. The three white dots engraved on the surface of the retainer mark the three points that contact your part. The two dots on the outer arms can be used independently as contacts for posts. For more information on using the anodized aluminum RSPC with a post, click here.
Note: The RSPC Position Retainer can also be secured to an optical table or breadboard via the CL6 clamp. This clamp is useful in situations where the RSPC cannot be placed directly over a hole in the table. The photos below illustrate the RSPC being secured to an optical table with both an 8-32 cap screw and the CL6 clamp.
RSPC Mounted Directly to Optical Table
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RSPC Secured by CL6 Clamp
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