Next Return Previous

heightec-PMI Twist D42A

Version A Version B
Version A Version B

Overview


Version A
(#268, 2140)

Front View: Closed Rear View: Closed
Front View: Closed Rear View: Closed
 
Front View: Open for Rigging Rear View: Open for Rigging
Front View: Open for Rigging Rear View: Open for Rigging

Technical Details

I acquired my heightec-PMI Twist D42A from On Rope 1 in 2009. I acquired another in 2017 as part of Bob Thrun's collection.

The heightec-PMI Twist D42A is 107 mm. tall, 71 mm. wide, 31 mm. thick, and weighs 142 g. Like most chest ascenders, this one is left-handed.

The ascender shell is a subtriangular orange anodized aluminum stamping 3.8 mm. thick. The rope channel is formed by bending the right side of the ascender into a U. The rope channel is 15.8 mm. in diameter. The main sling attachment point is located below the cam and behind the rope channel. A second attachment point is located above the cam and also behind the rope channel. The shell is bent backwards at both points to provide clearance between the attachment slings and the main rope. This accounts for the rather large thickness of this ascender. The attachment points appear to be circles distorted by the stamping and bending operation. The lower attachment point measures 17.5 by 16.5 mm. and the upper 16.6 by 13.7 mm. The left end of the shell is bent on an inclined axis to form another U. A hole drilled through both sides of the U accepts a semi-tubular rivet. The cam, cam spring, and a spacer washer are mounted on this rivet. The head of the rivet is in the front, while the roll is in the rear. The hole in the roll is nearly s deep as the shell is thick. The pivot is centered 47 mm. from the inside of the rope groove. There is a cylindrical cam stop riveted to the shell above the cam.

The cam is a plated skeletonized steel casting. The cam radius, measured from the pivot, increases from 38 to 52 mm. over an angle of 37°, giving a 26° cam angle. The cam has number of small conical teeth, all of which have their axes approximately perpendicular to the cam face. The tooth pattern is (1.2^3)^2(1.2)^2(B). The B stands for a small bar. A spring-loaded manual safety is mounted mounted on an axle riveted to the bottom center of the cam. The normal action of the spring holds the safety against the cam. The safety has a 12.8 mm. tall, 6 mm. diameter pin mounted on it for the fingers. When the cam is opened, the shell interferes with the safety, thus preventing cam opening. At full open the safety can be released and the spring will hold the tab against the back of the shell, locking the cam open.

The rear of the ascender is printed with a book-with-an-"i" icon, "D42A," "Ø8-13," "heightec-PMI," "www.heightec.com," and "1008 038."

Comments

The heightec-PMI is solidly made. All sharp edges have been removed. The attachment points are simply holes in the shell, and although rounded they should have been beveled more; even so, I would consider their small radius too sharp for directly attaching rope slings. The cam is the same as the cam on the other heightec-PMI ascenders (Pulsar D40, Compact D41A, and Rescue Compact D41A/ D44 Rope Grab/ D44A).

The cam stop is completely superfluous: the cam does not touch the cam stop, even when the ascender is off rope.

The safety is awkward to use with one hand (like the Petzl Basic). The cam and its teeth are very well made. I'm not sure what purpose the bar serves - several people have sent me emails telling me that the analogous bars on the Lucky AB-20 and VauDe AB-20 Bloquer keep the cam from closing and touching the shell (so what?), but the bar does not do touch the shell on the D42A. Perhaps it is there to keep the ascender from gripping small cord?? It certainly keeps the lower teeth from working effectively.

A major problem with the design is that the cam rubs against the cam axle channel whenever one tries to open the cam fully. This causes the cam to grate as I open or close it. I actually feel - and hear - a pronounced "click" as the cam binds and breaks free. This is definitely NOT a smooth-operating ascender.

At present, there are better chest ascenders on the market that sell for a similar price.


Version B
(#1502, 2141)

Front View: Closed Rear View: Closed
Front View: Closed Rear View: Closed
 
Front View: Open for Rigging Rear View: Open for Rigging
Front View: Open for Rigging Rear View: Open for Rigging

Technical Details

I acquired my heightec-PMI Twist D42A, Version B from On Rope 1 in 2009. I acquired another in 2017 as part of Bob Thrun's collection.

Version B is 103 mm. tall, 73 mm. wide, 38 mm. thick, and weighs 145 g. The only significant difference between Versions A and B is that Version B has a plastic safety.

The rear of the ascender is printed with a book-with-an-"i" icon, "D42A," "¤Ø8-13" (where the ¤ represents a circle with a dot inside), "heightec-PMI," "www.heightec.com," and "1108 092."

Comments

The new safety is also awkward to use; perhaps even more so than the one on Version A.