Kinematic Grating Mount Adapters for Ø1" Mirror Mounts

  • Compatible with all Ø1" Mirror Mounts
  • Accommodate Gratings up to 60 mm Tall
  • Spring-Loaded Clamping Design
  • Top-Located Locking Setscrew






Application Idea

KGM40 Grating Adapter, POLARIS-K1E Kinematic Mount, and GR25-030 Grating

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Holographic Grating Mounted in a Polaris Mirror Mount Using the KGM40 Kinematic Grating Mount Adapter


  • Mount Gratings or Rectangular Mirrors in Ø1" Mirror Mounts
  • Stable 3-Point Kinematic Mounting
  • Three Models Accommodate Optics up to 60 mm Tall

This simple, versatile family of anodized aluminum grating adapters is compatible with Thorlabs' Ø1", front-loading, unthreaded mirror mounts, including the POLARIS-K1E Ultra-Stable Kinematic Mirror Mount. Rectangular optics up to 60 mm tall may be mounted in the appropriate model (see table below; please note that for optics exactly 20 mm tall the KGM40 must be used.

Gratings and rectangular mirrors can be accommodated by simply sliding the upper and lower clamps on the adapter to match the desired optic height. These clamps slide in machined grooves and are tightened into place with two M3 screws located on the back side of the mount (see photo below). The 3-point, kinematic mounting mechanism consists of two bottom lines of contact and a top flat-spring contact as shown in the photo to the right. An additional nylon-tipped, locking setscrew located on the top clamp provides added holding force.

Grating Compatibility
Item # Grating Height Grating Width Grating Thicknessa
KGM20 <20 mm 12 mm (Min) 4 - 8 mm
KGM40 20 - 40 mm 18 mm (Min) 5 - 10 mm
KGM60 40 - 60 mm 32 mm (Min) 6 - 12 mm
  • Maximum thickness values are recommended. Thicker optics may not have sufficient contact with the mount to remain stable.
Back Side of Kinematic Grating Mount Adapter
Back Side of Adapter

Posted Comments:
Dhruvkumar Desai  (posted 2022-01-18 12:59:19.247)
Hello, is there a gap when fully closed? I'm not sure which directions the specs refer to as height, width, and thickness. I'm trying to use this to clamp down on a 1 mm thick piece of metal. Is there another product better suited?
jgreschler  (posted 2022-01-19 05:13:16.0)
Thank you for reaching out to Thorlabs. These mounts are unsuitable for mounting items less than 4mm thick. I have reached out to you directly to discuss possible alternatives from our product line.
James Good  (posted 2021-03-22 11:29:25.333)
Hello, an SM1 threaded KGM mount would be a nice varient for combining with SM1 threaded mounts like the K6XS, for example. The SM1-smoothbore adaptor leaves a lof of offset. Kind regards, James Good
YLohia  (posted 2021-03-23 10:25:24.0)
Hello James, thank you for your feedback. We will consider offering such an item in the future.
doron.azoury  (posted 2013-09-10 10:22:46.397)
Hi, i couldn't find information regarding the mount material. Is it vacuum (10-7mbar) compatible? Thanks.
cdaly  (posted 2013-09-11 16:59:00.0)
Response from Chris at Thorlabs: Thank you for using our feedback tool. The material of the KGM series of grating mounts is black anodized aluminum, which is not a material which we would say is vacuum compatible. We have stripped the anodization in the past to provide a custom vacuum compatible version. I will contact you to discuss this further.
tcohen  (posted 2012-10-07 10:30:00.0)
Response from Tim at Thorlabs: Thank you for contacting us! We would recommend using the KGM40 for a substrate exactly 20mm tall.
rwhi  (posted 2012-10-05 16:37:06.0)
Hi, would you recommend the KGM20 or KGM40 for a substrate exactly 20mm tall?
jjurado  (posted 2011-03-23 15:13:00.0)
Response from Javier at Thorlabs to jahan.dawlaty: Thank you very much for your feedback! I will share your comments with our mechanics department and keep you informed of all the details regarding this product.
jahan.dawlaty  (posted 2011-03-22 17:47:30.0)
It would be nice if this product (Kinematic Grating Mount Adapters) also allowed for grating rotation. Grating rotation (along with tip and tilt) is necessary for proper alignment.
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Kinematic Grating Mount Adapters

Based on your currency / country selection, your order will ship from Newton, New Jersey  
+1 Qty Docs Part Number - Universal Price Available
KGM20 Support Documentation
KGM20Kinematic Grating Mount Adapter (Grating Height <20 mm)
KGM40 Support Documentation
KGM40Kinematic Grating Mount Adapter (Grating Height: 20-40 mm)
KGM60 Support Documentation
KGM60Kinematic Grating Mount Adapter (Grating Height: 40-60 mm)