THE REMARKABLE RADION

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CAMP spent three years designing and tooling the Radion ice screw and the result is a product that field testers are calling the best screw they have ever used. Comparison tests with other screws praise the Radion for its impeccable driving action (it starts easier and faster than other screws and carries this performance through the entirety of the placement), ease of extraction (it does not get stuck or clogged like other screws), sensitivity in brittle ice (it puts less stress on the ice than other screws), and unique free-floating hanger pre-equipped with a Dyneema sling (a feature found only on the Radion).

Ice screws may be one of the most under appreciated pieces of gear on the climber’s rack. We think of a screw as a simple threaded device that penetrates a solid surface by turning and we think of mass production like the box of 500 we can pick up at Home Depot for $15. But even the screws in that box of 500 are under appreciated. How do product engineers determine the optimal circumference of the shaft and the angles and spacing of the threads? What blend of metal ensures adequate strength and durability? What shape should the tip be for the best possible penetration? That box of 500 screws may only cost $15, but it is filled will technological ingenuity just the same.

Now consider the technology of a $75 screw. It had better be remarkable to command that price! In truth, $75 is a bargain for a screw like the Radion whose manufacturing was only possible after three continuous years of research and development. Here, we dig deep into the technology behind the Radion. We explain why the Radion excels in the areas of driving action, ease of extraction and sensitivity in brittle ice. We also explore the benefits of the unique freefloating hanger.

An ice screw’s performance can be thought of much like an engine powering an automobile. If the engine won’t start, the car will not move. Similarly, if an ice screw does not penetrate ice, it will not establish a placement that inspires confidence and ensures safety. Now think of a race in which the cars must sit with their engines turned off until the flag drops. Each driver turns the key in the ignition and hits the gas. The faster the car starts, the better position the driver can gain from the outset. The same is true of ice screws and since ice climbing so often feels like a race (against the pump, the temps, the wind, etc.), every second counts. By its nature, ice climbing is dangerous. Ice conditions can change rapidly so it is always important to climb quickly and efficiently. The less time one spends on ice, the less likely they are to get hit by falling ice. Ice up to WI4 can feel easy and can be climbed very quickly by advanced ice climbers. In fact, many climbers can motor their way up almost an entire pitch of ice in the same amount of time it takes them to place a screw. Here at CAMP, we do not advocate solo climbing. As strong as we might become, we simply cannot anticipate every weak hold, the hidden wasp’s nest, or spontaneous falling debris common in alpine settings. As a result, responsibly placed protection is a requisite for safe climbing. Depending on the conditions of the ice, responsible spacing of screws can be as little as every fifteen feet. On a thirty meter pitch (~100 feet) this translates to six screws for progression and two for the anchor. Each screw must be placed with precision in the best ice available to ensure maximum safety. The more time it takes to place a screw, the more time you spend on the route and the more likely you are to become fatigued or get hit by ice.

The best ice screw establishes its thread with the greatest efficiency while optimizing safety. Efficiency can be defined as a combination of how easily and quickly a climber can create a solid placement with the screw. The best ice screw does not shatter the ice it is being turned into, drives straight to create a tight thread pattern in the ice and carries these properties through the entirety of the placement (i.e. the screw continues to penetrate the ice with the same efficiency from start to finish). Most ice screws do not have great starting action. They require several attempts and excessive force to establish the thread. As a result, the screw can substantially weaken the ice it is penetrating, drive at a less than optimal angle and create a less precise thread pattern with small gaps and fractures around the thread that can compromise the screw’s holding power. In field tests, reviewers consistently note that the Radion drives better than any other screws they have used. This is a result of many technological features.

First, the teeth on the Radion and the aggressive transition from the teeth to the threads have been optimized for penetrating ice. Each of the four front teeth is shaped with three different angles of milling. The slightest variation in these angles can have dramatic effects on initial penetration and the possibility of breaking fragile ice.

Second, the threads feature a reverse angle that distributes the force being applied to the ice more evenly and in the right direction. This has great advantages when dealing with a fragile and brittle material like ice. On a standard screw, the taper (angle) is often located on the leading edge of the thread. This design excels for hard, solid surfaces where the stress created by the screw is unlikely to affect the integrity of the material. But it is not an ideal design for fragile materials like ice. A tapered leading edge actually applies force in an outward direction (90 degrees to the angle of the thread) which can create stress fractures in ice. By reversing the thread, thereby leading with the flat wall of the thread, the force is applied along the same vector as the screw’s shaft and the pressure placed on the ice is more evenly distributed across the larger surface area of the thread. In other words, this design dramatically reduces the impact on the integrity of the ice around the screw. Reverse threads also make the screw easier to extract since the leading edge during extraction is the tapered angle.

Third, the Radion shaft is constructed from an optimal steel alloy using the same technology found in the barrel of a high-quality rifle. For firing a bullet, the variance in the inner circumference of the barrel must be extremely precise and the inner surface area of the barrel must be excessively smooth to ensure accuracy and safety. This presents a manufacturing conundrum. Post production buffing of the inner side walls will inevitably produce inconsistencies in the thickness of the sidewalls (it is easy to buff away a bit more material here and there). Any and all variance in the thickness of the shaft (or the sidewalls of the shaft) of a screw increases friction and decreases efficiency. With the barrel of a gun, a tight variance on the inner circumference is the main concern. With ice screws, we must also be concerned with the outer circumference. Once again, any and all variance in the thickness of the shaft or the sidewalls of the shaft increases friction and decreases efficiency. The Radion is manufactured with an acceptable variance of less than 0.03 mm. This means at any point, along the shaft of the screw, the thickness of the sidewall, the inner diameter and the outer diameter will not vary by more than 0.03 mm from the dead center of the inner circumference. Once the Radion shaft is turned and milled, CAMP uses the precise technology of CNC machining to mill the teeth. The shaft is
then heat treated for the right hardness and Nickel plated to help prevent rust.

Fourth, the Radion features a long, stiff lever constructed from nickel plated hardened steel alloy that makes each turn easier. The force required to turn the screw decreases substantially the further away the point of force applied to the lever moves from center point of the screw. We are spreading the force necessary to turn the screw over a longer distance which means every point in the turn requires less acceleration (i.e. less energy). The length of the lever, however, must consider a number of factors. First is the simple length. Longer is better as energy exertion goes, but make the lever too long and we will start being able to wobble the screw from side to side as we turn the lever. The lever will also simply get in the way (it will not rack efficiently and it will hit protrusions on the surface of the ice). Make the lever too short and the screw takes significantly more energy to turn. Ironically, this can also lead to wobble from side to side since we are unable to ensure perfect centripetal motion when we are struggling even to make a single turn. Second is the stiffness of the lever. A long lever that bends will lead to less than perfect centripetal motion meaning the force is being applied in all sorts of directions at any point along the turn. This is terribly inefficient and feels awkward. Finally, the handle or knob used to turn the lever must offer sufficient surface area and turn smoothly in order to maximize the efficiencies of the lever. A knob with little surface area is difficult to hold on to and a knob that does not turn smoothly will require the climber to start and stop the centripetal motion. Each time we are forced to restart the motion, we have to start from an acceleration of zero so it requires more energy to regain the force advantage generated by the lever before we were forced to stop turning the screw. The lever on the Radion was conceived as the optimal combination and compromise of all of these factors. The length and stiffness ensure mechanical advantage without increasing the likelihood of wobble and the knob turns smoothly to assist with more constant centripetal force.

Beyond these technological considerations of the shaft, lever, teeth and threads, the Radion also features an innovative free-floating hanger that is pre-equipped with a Dyneema sling. All other screws have a fixed hanger whose final placement is directly related to the penetration of the screw. The free-floating hanger on the Radion allows the climber to micro adjust its placement without compromising the depth of the screw’s penetration (i.e. the screw can be driven as deeply as possible). The 12 mm Dyneema sling offers multiple points for racking and allows the clipping point to be separated from the hanger. This is particularly useful when placing screws in pods where a biner clipped straight into the hanger will be forced to run over an edge and almost surely shatter the ice it is resting on in the case of a fall. And if the ice does not break, the carabiner is still being stressed along its weak axis. The choice of Dyneema is also strategic. It is hydrophobic and extremely strong. Ice climbing is often a wet activity, but climbers can rest assured that the Dyneema sling on the Radion will not absorb water or be compromised by repeated exposure to moisture (something to consider when putting together the rest of your ice rack).

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