Optical Component Threading Adapters with M25 x 0.75 Threads


  • Integrate M25 x 0.75 Threaded Components with Other Industry Standard Threads
  • Adapters Available with Either Internal or External M25 x 0.75 Threads

LSM03

SM1A12

SM1L10

M25A1

External M26 x 0.706 (36 TPI) Threads and Internal M25 x 0.75 Threads

RMSA1

External M25 x 0.75 Threads and Internal RMS Threads

M32A1

External M32 x 0.75 Threads and Internal M25 x 0.75 Threads

SM1A12 Adapter Connecting a Scan Lens to an SM1 Lens Tube

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Interactive Selection Guide

M25 x 0.75-Threaded Optical Component Adapters

This page contains all of our Optical Component Thread Adapters that feature M25 x 0.75 threading. Adapters that have both internal and external threads are available, as well as adapters with two sets of internal threads or two sets of external threads.

Our M25 x 0.75 adapters are a subset of our entire line of optical component thread adapters. To view our entire line, please see our Interactive Adapters Selection Guide.

For use with microscope objectives, we recommend our brass microscope objective threading adapters; the brass construction is harder than aluminum which reduces thread binding.

Adapters with External M25 x 0.75 and Internal Industry-Standard Threads
Item # Typical Application External Threads Internal Threads
RMSA1
info
 Integrate RMS Objective with
M25 x 0.75 Mount		 M25 x 0.75 RMS (0.800"-36)
SM1A11
info
 Integrate M25 x 0.75 Objective into
SM1 Lens Tube		 M25 x 0.75 SM1 (1.035"-40)
M32A2a
info
 Integrate M32 x 0.75 Objective with M25 x 0.75 Mount M25 x 0.75 M32 x 0.75
  • Threading types are laser engraved on these adapters.
Adapters with Internal M25 x 0.75 and External Industry-Standard Threads
Item # Typical Application External Threads Internal Threads
RMSA2
info
 Integrate Scan Lens into RMS Mount RMS (0.800"-36) M25 x 0.75
SM1A12
info
 Integrate Scan Lens into
SM1 Lens Tube		 SM1 (1.035"-40) M25 x 0.75
M25A1
info
 Integrate M25 x 0.75 Objective with M26 x 0.706 Mount M26 x 0.706
(36 TPI)		 M25 x 0.75
M32A1a
info
 Integrate M25 x 0.75 Objective with M32 x 0.75 Mount M32 x 0.75 M25 x 0.75
M32M25Sb
info
 Integrate M25 x 0.75 Objective with M32 x 0.75 Mount M32 x 0.75 M25 x 0.75
SM2A33a
info
 Integrate M25 x 0.75 Objective
into SM2 Lens Tube		 SM2 (2.035"-40) M25 x 0.75
GCMA1a info Integrate M25 x 0.75 Scan Lens
into Galvo Mirror Mounting Adapter		 SM2 (2.035"-40) M25 x 0.75
  • Threading types are laser engraved on these adapters.
  • This brass adapter has a flange to prevent overthreading the adapter or the objective into a microscope nosepiece. Brass is harder than aluminum which reduces thread binding.

Thorlabs' Threading Specifications

Thorlabs' lens tubes utilize a series of non-standard threadings. Threading specifications are given below for our SM threadings utilized in our lens tube and cage system components so that you can machine mating components to suit your application. We also offer products with C-Mount and RMS threadings, and the specifications for these threadings are also given below. Please note that other manufacturers may have different tolerances for these threads. For other thread specifications that are not listed here, please contact Tech Support.


Click to Enlarge
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, M30.5x0.5 Internal Thread, M30.5x0.5
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"

Posted Comments:
user  (posted 2019-05-28 17:37:25.987)
Dear Thorlabs Team, One reason we would like to use this M25x0.75 adapter is to mount the Olympus 20X water-dipping objective lens: https://www.thorlabs.com/thorproduct.cfm?partnumber=N20X-PFH However, the thread part of that objective lens is 5.8 mm long, while the internal M25x0.75 thread of this SM1A12 adapter is less than 5 mm long, which can affect the stability and parfocal length when we need to switch the objective on the microscope. Could Thorlabs adapt this one with a longer (i.e. deeper) internal M25x0.75 thread, so that the adapter lip can get in contact with the locating flange of the objective? Thank you very much! Best, Wenxuan
llamb  (posted 2019-05-29 10:31:54.0)
Hi Wenxuan, thank you for your feedback. This thread depth/length issue has been brought to the attention of our engineering teams, as there are varying thread lengths for our objectives with M25 x 0.75 threading that need to be accounted for. I have reached out to you directly to discuss the possibility of a custom thread adapter in the meantime.
thiel  (posted 2017-07-13 15:17:29.5)
Could I get a single adapter with diameter: M25 x 0.5 (inner) to M27 x 0.75 (outer) Could I get another single adapter with diameter: M25 x 0.75 (inner) to M27 x 0.75 (outer)
tfrisch  (posted 2017-07-28 02:18:09.0)
Hello, thank you for contacting Thorlabs. I will reach out to you with a quote.

Adapters with External M25 x 0.75 and Internal Industry-Standard Threads

Based on your currency / country selection, your order will ship from Newton, New Jersey  
+1 Qty Docs Part Number - Universal Price Available
RMSA1 Support Documentation
RMSA1Customer Inspired! Adapter with External M25 x 0.75 Threads and Internal RMS Threads
$22.59
Today
SM1A11 Support Documentation
SM1A11Adapter with External M25 x 0.75 Threads and Internal SM1 Threads
$23.53
Today
M32A2 Support Documentation
M32A2Customer Inspired! Adapter with External M25 x 0.75 Threads and Internal M32 x 0.75 Threads
$26.21
Today

Adapters with Internal M25 x 0.75 and External Industry-Standard Threads

Based on your currency / country selection, your order will ship from Newton, New Jersey  
+1 Qty Docs Part Number - Universal Price Available
RMSA2 Support Documentation
RMSA2Customer Inspired! Adapter with External RMS Threads and Internal M25 x 0.75 Threads
$26.21
Today
SM1A12 Support Documentation
SM1A12Adapter with External SM1 Threads and Internal M25 x 0.75 Threads
$23.53
Today
M25A1 Support Documentation
M25A1Adapter with External M26 x 0.706 Threads and Internal M25 x 0.75 Threads
$30.26
Today
M32A1 Support Documentation
M32A1Customer Inspired! Adapter with External M32 x 0.75 Threads and Internal M25 x 0.75 Threads
$26.21
Today
M32M25S Support Documentation
M32M25SCustomer Inspired! Brass Microscope Adapter with External M32 x 0.75 Threads and Internal M25 x 0.75 Threads
$22.84
Today
SM2A33 Support Documentation
SM2A33Adapter with External SM2 Threads and Internal M25 x 0.75 Threads
$29.69
Today
GCMA1 Support Documentation
GCMA1Adapter with External SM2 Threads and Internal M25 x 0.75 Threads, Ø35.0 mm Counterbore
$59.08
Today
Additional Optical Component Thread Adapters
  • SM05-Threaded Adapters

  • RMS-Threaded Adapters

  • M25 x 0.75-Threaded Adapters

  • C-Mount-Threaded Adapters

  • SM1-Threaded Adapters

  • M32 x 0.75-Threaded Adapters

  • SM1.5-Threaded Adapters

  • SM2-Threaded Adapters

  • M52 x 0.75-Threaded Adapters

  • SM3-Threaded Adapters