Rail Carriage for 66 mm Rails

  • Side-Locked Mounting Platform that Slides Along Rail
  • Contains Array of 1/4"-20 (M6), 8-32 (M4), and 6-32 Tapped Holes
  • Attaches to Side or End of Rail


Attached to Rail End

with Standard

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Mechanical Drawing of Imperial Version
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Mechanical Drawing of Metric Version


  • Insert and Remove Anywhere Along a Rail Side
  • Slides Along Rail Side Prior to Lockdown
  • Attachable to Rail End with M3 Cap Screws
  • Wide Assortment of 1/4"-20 (M6), 8-32 (M4), and 6-32 Tapped Holes

The XT66P2(/M) Rail Carriage consists of a closely packed array of six 1/4"-20, four 8-32, and seven 6-32 tapped holes (six M6 and eleven M4 taps in the metric version), along with a centered 1/4" (M6) counterbore. It fastens to a 66 mm rail by tightening the included side-mounted 9/64" (M3) locking screw. The swinging clamping arm provides ample clearance to lift the carriage off when the locking screw is loosened, permitting the carriage to be installed anywhere along an exposed rail side. The position of the rail carriage can be finely adjusted using Thorlabs' XT66N Rail Platform Positioner.

This rail carriage also contains four counterbored holes at the corners, positioned such that the XT66P2(/M) can fasten to the end of a standard 66 mm rail using four M3 cap screws (not included), as shown in the image at the top of the page. In this orientation, the clamping arm is free to hold another 66 mm rail at a right angle. Alternatively, optomechanics can be attached to the rail ends.

Thorlabs offers an extensive selection of accessories for 66 mm rails, including clamps and angle brackets, breadboard mounts, mounting platforms, rail carriages, rail platform positioners, rotation slide platforms, rail joiners, and lens tube adapters. Together with size adapters that incorporate 34 mm and 95 mm rails into an XT66 setup, these tools provide a complete family of rigid, versatile building blocks suited for virtually any optomechanical setup.

Posted Comments:
user  (posted 2014-12-30 14:50:56.52)
Hello, The drawing for part XT66P2 does not indicate the distance between the two sets of 1/4"-20 tapped holes and the center one. I checked the drawing of the metric version and that one has the missing dimension, although it's probably different for the imperial part as other dimensions are too.
cdaly  (posted 2014-12-31 09:46:49.0)
Response from Chris at Thorlabs: In the drawing, the vertical distance of each horizontal pair of 1/4"-20 holes from the center line is 0.75". I will try to have this added to mirror the metric version as soon as possible. Thank you for pointing it out.
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+1 Qty Docs Part Number - Imperial Price Available
XT66P2 Support Documentation
XT66P2Rail Carriage for 66 mm Rails with 6-32, 8-32, & 1/4"-20 Taps
+1 Qty Docs Part Number - Metric Price Available
XT66P2/M Support Documentation
XT66P2/MRail Carriage for 66 mm Rails with M4 & M6 Taps
Last Edited: Aug 29, 2013 Author: Dan Daranciang