Gstrings - The Development Process
We’ve been experimenting with ideas based on a logarithmic spiral shaped grip and a four point adjustable sling arrangement since the mid-90s. The goal has always been a versatile training product for climbers that offers as many grip positions as possible, but in a small form factor. A couple different ideas/versions were even shopped around to several well-known companies but never resulted in a commercial product for climbers. Here’s some of that process shown through photos, though not necessarily in chronological order.
      

      
      
        
    

    
Final prototype
After finalizing the adjustable four-point sling and significant testing of the last prototype above, we felt like we were close enough to what we envisioned for a marketable product that we decided to go ahead with a final pre-production version using the target material - aluminum. By moving to aluminum we were able to create the exact size and shape since there were no material constraints like there were with some of the other materials. A final modification included the elliptical crimper which can be changed from easy to hard just by its orientation. 
Two climbing friends, Brian and Alex, provided the expertise we needed to create the aluminum prototype. Brian is a mechanical engineer who took my notes and rough computer drawings and put them into SolidWorks CAD software and turned it into a virtual model. He used the virtual model for testing to make sure the Gstrings would be strong enough to endure the actual stresses that it might be subject to during use. This was followed by actual physical tests, to confirm the CAD modeling. 
Alex, a machinist and consultant in relation to all things metal, took Brian’s Sold Works specifications and input them into an EDM (Electrical Discharge Machining) to cut the actual prototype. The prototypes were cut from a 40 lb. solid block of 6061-T6 aluminum! Here are some photos from that process and the end result. The EDM machine is an incredible piece of equipment!
            
Production version
After stress tests and and several months of user feedback, we made final adjustments to the SolidWorks specs. This included thinning non-critical structural walls to reduce weight and over-all size slightly, and adding an ergonomic curve to the flat edge for more comfort while also making it more joint and tendon friendly. We then sent the specs to a extrusion manufacturer to machine a die and extrude 8’ lengths of the “G” tubing to be used in the production of the end product. Lastly, various jigs were created to make chopping, slicing, drilling, and various aspects of assembly more accurate and efficient.
       
It’s been a long but rewarding process to see this project through from a felt need, to an idea, a design, various prototypes, and finally into small scale production.
We're now in the process of applying for a patent on both spiral grips and the 4-point adjustable suspension in various forms, which have wider application than this specific product. Look for new offerings in the future!
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