Clog (twistlock D) (diagonal knurling - 2500)

(twistlock D) (diagonal knurling - 2500)

Name:Clog (twistlock D) (diagonal knurling - 2500)
Category:twist lock
Locking Type:full-auto
Unlock Style:twist
Sleeve Rotation:90° (unlocked) | >90° (maximum)
Shape:asymmetric D
Nose:notch & pin
Nose Guard:none
Rivets:domed: sharp edged
Gate Shield:none
Weight:80.5 g
Dimensions:Length: 109.50 mm
Width: 63.54 mm
Depth (basket end): 9.58 mm
Gate Opening: 20.00 mm
Strength Ratings:Major Axis: 2500
Other Markings:Impressed: CLOG 2500 U.I.A.A. WALES | ELITE DIN 7944
Collection Criteria:★ Mechanically Interesting
★ Historically Interesting or Iconic
Summary:early twistlock, possibly even the first twistlock model
Description & Commentary:

This design is one of the first autolocking carabiners.

Clog produced the first twistlock carabiners, with advertisments appearing in 1983. These ads show drawings with a sleeve design using diagonal knurling and a 90 degree throw, which suggest this style predates straight knurling and 120 degree throw. The excellent Scottish Mountaineering Heritage Collection has similar carabiners, but they have different markings (3000 kg vs 2500 kg).

The twist spring feels light in comparison to modern carabiners - not sure if this is a function of age or design. As with most modern autolockers, the hinge pin includes a lug to guide the locking mechanism. Notably, this is much larger diameter than found these days.

If you can assist with any information regarding the original twist lock designs by Clog, please Contact Me.

Clippings:Catalog & Magazine Clippings