My Kong-Bonaiti ascenders were obtained from Bob & Bob in the summer of 1987. Both ascenders in the pair are left-handed. Each ascender is is 117 mm. high, 77 mm. wide, 40 mm. thick, and weighs 153 grams. 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 15.5 mm. in diameter. Two indentations in the stamping extend from the back of the ascender around the rope channel; these would serve to strengthen the rope channel against unrolling. 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 20.5 by 18 mm. and the upper 18 by 13.5 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 rolled rivet. The cam, cam spring, and a spacer washer are mounted on this rivet. The head of the rivet sits into a stamped depression on the back of the cam, while the roll is exposed on the open side. The pivot is centered 46 mm. from the inside of the rope groove.
The cam is a skeletonized casting. The cam radius, measured
from the pivot, increases from 38 to 58 mm. over an angle of 36
degrees. The cam has number of small conical teeth, all of which
have their axes approximately parallel to the upper surface of
the cam. In between the teeth rows are four oval holes which open
to the central vacancy of the cam. The holes and teeth both decrease
in size towards the toe of the ascender. The tooth/hole pattern
is (3.4)(H.3)^3(H.2.1); i.e., a row of 3 teeth, a row of 4 teeth,
three sets of a hole followed by a row of 3 teeth, a hole, a row
of two teeth, and a single tooth. A spring-loaded manual safety
bar is mounted on the bottom of the cam with a somewhat cracked
steel roll rivet. The normal action of the spring holds the safety
against the cam. When the cam is opened, the shell interferes
with the safety bar, thus preventing opening the cam. If the safety
bar is moved away from the cam (opposing the spring), it will
clear the shell and the cam will open. At full open the safety
can be released and the spring will hold the safety against the
back of the shell. This provides a means of locking the cam open.
A cylindrical knob on the safety bar assists in operating the
safety mechanism.
The back of the shell is stamped "STATIC ROPE", "Ø9 KG. 420","Ø11 KG. 500", and "KONG-BONAITI-ITALY". The front of the cam is stamped "CAM-CLEAN".
In general I feel that this is a well made ascender. All sharp edges have been removed. The cam teeth are rather well done, though not quite as well as some of my older Petzl's. The shell reinforcing is a nice touch, though of course I can't quantify its strength benefit. Similarly, I am unwilling to destroy ascenders to verify manufacturer's strength claims, but I am satisfied that this ascender is strong enough for my own personal use.
The ascender was designed as a chest ascender for the Frog System, and hence the Kong-Bonaiti is particularly applicable to this system. According to a letter I received from Kong (dated 26 Jan, 1989), they originally developed his shell shape, and it was later copied by other manufacturers. Most other applications are not so shell shape sensitive, and hence the Kong-Bonaiti could easily substitute for any other ascender in this article in almost any legitimate situation.
As with most ascenders under discussion, single handed operation of the Kong-Bonaiti is rather difficult. The better handled ascenders are much easier to operate. I find right-handed operation particularly difficult, as might be expected for a left-handed ascender. Closing an locked open ascender is much easier than opening, since the strong cam spring assists the user.
The attachment points are simply holes in the shell, and although well rounded I consider their small radius too sharp for directly attaching sling ropes. They are probably acceptably rounded for webbing, but considering the proximity of the attachment points to the main rope, I would recommend using a small maillon for most attachments in order to reduce the risk of sling abrasion.
Orienting the cam teeth parallel to the top of the ascender cam imparts a slight downwards alignment with respect to the climbing rope. This increases their grip, reduces tooth friction while raising the ascender, and provides a small self cleaning action at the same time. The holes in the cam are intended to reduce the risk of ascender slippage due to mud-caked cam teeth. This may be of some benefit under certain caving conditions,particularly with wet silty muds, but my experience is that caves that have enough mud to clog ascender teeth usually have enough mud to stop a bulldozer. I suspect that most ropes muddy enough to stop other ascenders will stop the Kong-Bonaiti too, despite the mud holes. Although I have not tried this ascender in the appropriate conditions, I suspect that the holes will not eliminate the icing problems common to other toothed cam ascenders.
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©2007, Gary D. Storrick