SM-R2 Series Ø2-Inch Fixed Mounts

Product Description

• SM2 (2.035”-40) internal threads for Ø2-inch optical components or lens sleeves.
• M4 threaded mounting holes at the bottom for installing Oeabt series rods.

The SM-R2 series fixed mounts feature SM2 (2.035”-40) internal threads, designed for mounting Ø2-inch optical components or externally threaded lens sleeves. The M4 threaded holes at the bottom facilitate installation onto Ø12mm stainless steel rods for free-space applications.

Model	SM-R2	SM-R2A
Dimensions	55.9*12.7*62.5mm	55.9*12.7*62.5mm
Central Aperture	SM2 (2.035”-40) partial threads	SM2 (2.035”-40) full threads
Thread Type	M4	M4
Weight	18.3g	19.1g
Material	7075 aluminum alloy	7075 aluminum alloy

Technical Description

Optical Knowledge Point: Common Optical Thread Size Standards

This is a thread specific to Thorlabs Inc. (USA) and not a commonly used optical thread. “SM” is the code for sewing machine threads in thread notation, but this American company uses it for internal and external thread connections of optical lenses and sleeves. The thread type is UNS (Unified National Special Thread) with a tolerance class of 2A/2B. A unique feature of this thread is that regardless of the diameter, the pitch is 40 threads per inch (TPI). Specific dimensions are as follows:

Series	Type	Thread (in)	Nominal Diameter (mm)	Minor Diameter (mm)	Pitch Diameter (mm)	Major Diameter (mm)
SM05	Internal	0.535-40	13.59	12.98±0.07	13.24±0.05	＞13.59
SM05	External	0.535-40	13.59	＜12.78	13.10±0.05	13.50±0.05
SM1	Internal	1.535-40	26.29	25.68±0.07	25.95±0.05	＞26.29
SM1	External	1.535-40	26.29	＜25.48	25.79±0.05	26.19±0.06
SM2	Internal	2.535-40	51.69	51.08±0.075	51.35±0.075	＞51.69
SM2	External	2.535-40	51.69	＜50.87	51.18±0.05	51.59±0.05

Product Description

The SM-R2 series fixed mounts feature SM2 (2.035”-40) internal threads, designed for mounting Ø2-inch optical components or externally threaded lens sleeves. The mounts are available in full-thread and partial-thread versions, with included retaining rings for fixing optical components.

The SM-R2 has SM2 (2.035”-40) partial threads and can mount optical components up to 9.5mm thick. The SM-R2A has SM2 (2.035”-40) full threads and can mount optical components up to 9.0mm thick

The M4 threaded holes at the bottom facilitate installation onto Ø12mm stainless steel rods for free-space applications. We also offer the SM-R1 Ø1-inch fixed mount as an alternative.

Assembly

Application Example

Engineering Drawing Download

SM-R2A-Engineering Drawing

SM-R2-Engineering Drawing