Vacuum-Compatible Kinematic Mirror Mount

  • Ø1" Kinematic Mount for Vacuum Use
  • Shipped in a Single Vacuum Bag
  • Constructed from 6061-T6 Aluminum with Phosphor Bronze Bushings and 304 Stainless Steel Adjusters

Application Idea

Replace the included manual adjuster screws with PIAK10VF Vacuum-Compatible Piezoelectric Inertia Actuators.


For Ø1" Optics

Back View

Front View

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Additional Vacuum-Compatible Components

Many of our other optomechanical components can be special ordered for vacuum use. Contact for details.


  • Internally SM1-Threaded (1.035"-40) Optic Cell
  • Mount Ø1" Optics Up to 0.28" (7.1 mm) Thick Using Included SM1RRV Retaining Ring
  • ±4° of Pitch and Yaw Adjustment
    • Mount Includes 1/4"-100 Adjusters with Removeable Knobs
    • Adjusters can be Replaced with PIAK10VF Vacuum-Compatible Piezo Inertia Actuators
  • Counterbored #8 (M4) Through Holes Allow for Left-Handed or Right-Handed Orientation
  • Unanodized 6061-T6 Aluminum Body, Phosphor Bronze Bushings, and 304 Stainless Steel Adjusters
  • Compatible with >10-6 Torr Environments Directly Out of the Packaging

Thorlabs' KS1TV Kinematic Mount provides pitch-yaw adjustment for Ø1" (or Ø25 mm) optics in vacuum environments down to 10-6 Torr. This mount features SM1 (1.035-40) internal threading with a depth of 0.36" (9.1 mm), providing room to house Ø1" optics up to 0.28" (7.1 mm) thick. Optics can be secured against a retention lip with an included SM1RRV vacuum-compatible retaining ring, which has a Ø0.90" (22.9 mm) clear aperture. The retaining ring can be threaded in place using an SPW606 Spanner Wrench.

Three 304 stainless steel 1/4"-100 TPI adjusters mounted in phosphor bronze bushings translate the front plate of the mount, providing the ±4º adjustment range. The spacing between the front and back plate must be 0.120" (3.05 mm) for the adjustment range to be symmetric (i.e., ±4°). When using all three adjusters, the kinematic mount can achieve a maximum Z translation of 0.25" (6.4 mm). Each adjuster can be turned using the adjuster knob or by inserting a 5/64" (2.0 mm) hex key through the knob to the screw's socket for fine adjustment. The knobs can also be removed by placing a 5/64" (2.0 mm) hex key into the adjuster, holding it in place, and unscrewing the knob from the adjuster. This can reduce the overall footprint of the mount when space is at a premium and allow for the installation of POLARIS-LN1 locking nuts. Each adjuster can be removed and replaced with our PIAK10VF vacuum-compatible piezoelectric inertia actuators, as shown in the image above, enabling angular adjustments with a typical resolution of 0.5 µrad.

#8 (M4) counterbored mounting holes allow for post mounting in either left- or right-handed orientations. The KS1TV mount ships with two screws, one 8-32, 0.5" long (Item # SH8S050V) and one M4 x 0.7, 12 mm long (Item # SH4MS12V), for mounting to our line of vacuum-compatible Ø1/2" posts. Optical post assemblies can be fastened to unanodized aluminum breadboards, which are also vacuum compatible to 10-6 Torr when properly cleaned by the user. When building assemblies for vacuum systems, remember to use vented screws to prevent trapping air in blind threaded holes.

For applications requiring high thermal stability and low beam drift while under vacuum, Thorlabs offers Polaris® Precision Mirror Mounts and accessories.

Vacuum Compatibility Information
This vacuum-compatible mount is chemically cleaned and prepared for vacuum applications before packaging. It is compatible directly out of the packaging with vacuum environments down to 10-6 Torr. With additional cleaning and processing, it can be used at even lower pressures, only limited by the outgassing rate of the constituent parts. The 6061-T6 aluminum body of the mount has the highest outgassing rate of the materials used. The material properties of the mount and the cleaning methods completed by the end user should be used to determine the appropriateness of using this mount and its materials in a specific vacuum system.

Item # Optic Diameter Maximum Optic Thickness Optical Axis Height Angular Adjustment Number of Adjusters Type of Adjusters Adjuster
Clear Aperture Mounting
KS1TV 1" or
25.0 mm
(7.1 mm)
(25.4 mm)
±4º 3 Removeable Knoba 1/4"-100 Ø0.90"
(Ø22.9 mm)
#8 (M4) Counterbored Holes,
2 Places

Threading Specifications

The following is a general overview of screw threading. For more details regarding specifications and dimensions, please consult the Machinery's Handbook, available for purchase at many bookstores.

Features of a Thread
A thread consists of three repeating features: a crest, flank, and root (see drawing to the right). Except in special cases, threads have symmetrical sides inclined at equal angles when a vertical line is drawn through the center of a crest or root. The distance between corresponding points on adjacent threads is known as the pitch of the thread. The flank angle is defined as the angle the flank makes with a perpendicular ray drawn from the screw axis. Unless otherwise stated, threads have a flank angle of 30°, resulting in a total angle between flanks of 60°. Each feature is shown in the diagram to the right.

The major diameter is taken from the crests of a thread while the minor diameter is taken from the roots. For most screws, crests and roots do not terminate at a sharp point, so crest and root truncation values are included in the definitions of major and minor diameter. The pitch diameter is approximately halfway between the major and minor diameters.

Thread Form
A thread form is a set of rules that define the features' scale relative to one another. Common thread forms include the Unified Screw Thread Form, used in the United States of America and measured in imperial units, and the ISO Metric Screw Thread Form, used in many parts of the world and measured with the International System of Units. There are many thread forms in the Unified screw thread standard designated by either UN, which defines a flat root contour, or UNR, which defines a round root contour. These can be further described by appending more letters. For example, an extremely fine thread with a flat root contour is designated UNEF. Those forms which are not standardized by the Unified screw thread system are designated UNS.

Thread Series
Most screws are identified by their thread series. Thread series are denoted by the major diameter and density of threads. Unified threads specify density in threads per inch, while Metric threads specify the thread pitch. For example, in the Unified nomenclature, a 1/4"-20 cap screw has a 1/4" diameter barrel and the pitch is 20 threads per inch (TPI). In metric nomenclature, an M4 x 0.7 cap screw has a 4 mm barrel and the pitch is 1 thread per 0.7 mm. The term M4 x 0.7 is often shortened to just M4.

Unified Thread Class Tolerancing
Location Loose Optimal Strict
Internal 1B 2B 3B
External 1A 2A 3A
Metric Thread Tolerance Positions
Location Loose Optimal Strict
Internal - G H
External e or f g h
Metric Thread Tolerance Grades
Dimension Location Tolerance Gradesa
Minor Diameter Internal 4, 5, 6, 7, 8
Major Diameter External 4, 6, 8
Pitch Diameter Internal 4, 5, 6, 7, 8
External 3, 4, 5, 6, 7, 8, 9
  • The tolerance becomes looser as the grade increases. The underlined grades are used with normal lengths of thread engagement.

Thread Class
The tolerances and allowances on a thread series are given by a thread class. Unified thread classes are alphanumeric identifiers starting with a number from 1 through 3, where 1 is the loosest tolerance and 3 is the tightest, and either A for external threading or B for internal threading.

Metric threads have a slightly more complex tolerancing method that uses tolerancing grades, designated by a number 3 through 9; and tolerancing positions, which use letters e through h. Grades provide a measure of the tolerance itself: the smaller the number, the tighter the tolerance. Positions denote the distance of the tolerance from the pitch diameter. Uppercase positioning letters indicate internal threads while lowercase positioning letters indicate external threads.

Quoting from the Machinery's Handbook, 29th Edition, p. 1885: "To designate the tolerance class, the grade and position of the pitch diameter is shown first followed by that for the major diameter in the case of the external thread or that for the minor diameter in the case of the internal thread, thus 4g6g for an external thread and 5H6H for an internal thread. If the two grades and positions are identical, it is not necessary to repeat the symbols, thus 4g, alone, stands for 4g4g and 5H, alone, stands for 5H5H."

Thorlabs' SM Series Threads
Threading specifications for our SM threads, utilized in our lens tube and cage system components, are given below so that you can machine mating components to suit your application. Most SM series threads utilize a non-standard Unified thread form, indicated by the letters UNS, with a 30° flank angle and a thread class of 2A and 2B. The exception is our SM30 series thread, which is a Metric thread form with a 30° flank angle and a tolerance of 6H/6g. We also offer products with C-Mount and RMS threads, and the specifications for these threads are given below for reference. Please note that other manufacturers may have different tolerances for C-Mount and RMS threads. For other thread specifications that are not listed here, please contact Tech Support.

SM05 Threading: Ø1/2" Lens Tubes, 16 mm Cage Systems
External Thread, 0.535"-40.0 UNS-2A Internal Thread, 0.535"-40.0 UNS-2B
Max Major Diameter 0.5340" Min Major Diameter 0.5350"
Min Major Diameter 0.5289" Min Pitch Diameter 0.5188"
Max Pitch Diameter 0.5178" Max Pitch Diameter 0.5230"
Min Pitch Diameter 0.5146" Min Minor Diameter (and 83.3% of Thread) 0.508"
Max Minor Diameter 0.5069" Max Minor Diameter (and 64.9% of Thread) 0.514"
RMS Threading: Objective, Scan, and Tube Lenses
External Thread, 0.800"-36.0 UNS-2A Internal Thread, 0.800"-36.0 UNS-2B
Max Major Diameter 0.7989" Min Major Diameter 0.8000"
Min Major Diameter 0.7934" Min Pitch Diameter 0.7820"
Max Pitch Diameter 0.7809" Max Pitch Diameter 0.7866"
Min Pitch Diameter 0.7774" Min Minor Diameter (and 83.3% of Thread) 0.770"
Max Minor Diameter 0.7688" Max Minor Diameter (and 64.9% of Thread) 0.777"
C-Mount Threading: Machine Vision Lenses, CCD/CMOS Cameras
External Thread, 1.000"-32.0 UN-2A Internal Thread, 1.000"-32.0 UN-2B
Max Major Diameter 0.9989" Min Major Diameter 1.0000"
Min Major Diameter 0.9929" Min Pitch Diameter 0.9797"
Max Pitch Diameter 0.9786" Max Pitch Diameter 0.9846"
Min Pitch Diameter 0.9748" Min Minor Diameter (and 83.3% of Thread) 0.966"
Max Minor Diameter 0.9651" Max Minor Diameter (and 64.9% of Thread) 0.974"
SM1 Threading: Ø1" Lens Tubes, 30 mm Cage Systems
External Thread, 1.035"-40.0 UNS-2A Internal Thread, 1.035"-40.0 UNS-2B
Max Major Diameter 1.0339" Min Major Diameter 1.0350"
Min Major Diameter 1.0288" Min Pitch Diameter 1.0188"
Max Pitch Diameter 1.0177" Max Pitch Diameter 1.0234"
Min Pitch Diameter 1.0142" Min Minor Diameter (and 83.3% of Thread) 1.008"
Max Minor Diameter 1.0068" Max Minor Diameter (and 64.9% of Thread) 1.014"
SM30 Threading: Ø30 mm Lens Tubes
External Thread, M30.5 x 0.5 – 6H/6g Internal Thread, M30.5 x 0.5 – 6H/6g
Max Major Diameter 30.480 mm Min Major Diameter 30.500 mm
Min Major Diameter 30.371 mm Min Pitch Diameter 30.175 mm
Max Pitch Diameter 30.155 mm Max Pitch Diameter 30.302 mm
Min Pitch Diameter 30.059 mm Min Minor Diameter (and 83.3% of Thread) 29.959 mm
Max Minor Diameter 29.938 mm Max Minor Diameter (and 64.9% of Thread) 30.094 mm
SM1.5 Threading: Ø1.5" Lens Tubes
External Thread, 1.535"-40 UNS-2A Internal Thread, 1.535"-40 UNS-2B
Max Major Diameter 1.5339" Min Major Diameter 1.535"
Min Major Diameter 1.5288" Min Pitch Diameter 1.5188"
Max Pitch Diameter 1.5177" Max Pitch Diameter 1.5236"
Min Pitch Diameter 1.5140" Min Minor Diameter (and 83.3% of Thread) 1.508"
Max Minor Diameter 1.5068" Max Minor Diameter (and 64.9% of Thread) 1.514"
SM2 Threading: Ø2" Lens Tubes, 60 mm Cage Systems
External Thread, 2.035"-40.0 UNS-2A Internal Thread, 2.035"-40.0 UNS-2B
Max Major Diameter 2.0338" Min Major Diameter 2.0350"
Min Major Diameter 2.0287" Min Pitch Diameter 2.0188"
Max Pitch Diameter 2.0176" Max Pitch Diameter 2.0239"
Min Pitch Diameter 2.0137" Min Minor Diameter (and 83.3% of Thread) 2.008"
Max Minor Diameter 2.0067" Max Minor Diameter (and 64.9% of Thread) 2.014"
SM3 Threading: Ø3" Lens Tubes
External Thread, 3.035"-40.0 UNS-2A Internal Thread, 3.035"-40.0 UNS-2B
Max Major Diameter 3.0337" Min Major Diameter 3.0350"
Min Major Diameter 3.0286" Min Pitch Diameter 3.0188"
Max Pitch Diameter 3.0175" Max Pitch Diameter 3.0242"
Min Pitch Diameter 3.0133" Min Minor Diameter (and 83.3% of Thread) 3.008"
Max Minor Diameter 3.0066" Max Minor Diameter (and 64.9% of Thread) 3.014"
SM4 Threading: Ø4" Lens Tubes
External Thread, 4.035"-40 UNS-2A Internal Thread, 4.035"-40.0 UNS-2B
Max Major Diameter 4.0337" Min Major Diameter 4.0350"
Min Major Diameter 4.0286" Min Pitch Diameter 4.0188"
Max Pitch Diameter 4.0175" Max Pitch Diameter 4.0245"
Min Pitch Diameter 4.0131" Min Minor Diameter (and 83.3% of Thread) 4.008"
Max Minor Diameter 4.0066" Max Minor Diameter (and 64.9% of Thread) 4.014"

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Vacuum-Compatible Ø1" SM-Threaded Kinematic Mirror Mount

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KS1TV Support Documentation
KS1TVVacuum-Compatible SM1-Threaded Precision Kinematic Mirror Mount for Ø1" Optics, 3 Adjusters