Rock Prodigy Training Center and Rock Prodigy Forge hangboards are revolutionary tools for developing elite finger strength. The split board design allows you to customize it to fit your body, improving the ergonomics, making it safer to train hard, and really boost your finger strength!
To really take the most advantage of the split design, you can mount the two halves in a way that allows the spacing and rotation to be adjusted on-the-fly…an “Adjustable Mount”.
The picture below shows one way to utilize the Adjustable Mount to enhance your training. In this pic, I’m training my “Index-Middle” 2-finger pocket. If you’ve tried this, you know that your fingers never fit in the pockets quite right because the middle finger is so much longer than the index. With the adjustable mount, I’ve widened the board spacing, and rotated the boards by placing shims under the outside mounting brackets (Counter-clockwise on the right, and clockwise on the left). This vastly improves the ergonomics, reducing skin wear and flapper potential. This makes a once-awkward grip really fun to train, and my IM 2F strength has improved substantially.
In two previous articles, we’ve presented methods for creating adjustable mounts: Adjustable Mount for the RPTC and Adjustable Mount 2.0 for the Rock Prodigy Training Center. The first method uses a “French Cleat” system:
RPTC mounted with French Cleat
The second method uses fence post brackets bolted to a backing board that allows it to slip over a fixed-mounted 2×10:
Fence brackets mounted to the RPTC. These easily slide over a 2×10 beam.
The RPTC with Adjustable Mount.
Recently we developed the all-new Rock Prodigy Forge, (see this post to understand how awesome it is: The World’s Most Technologically Advanced Finger Training System – The Forge) This hangboard is super-kick-ass, but it’s a little shorter than the RPTC, so I wasn’t sure my “Adjustable Mount 2.0” would fit on it. Therefore, I had the motivation to finally try an idea I’d had for an easier Adjustable Mount, that I’ll describe now.
In a nutshell, this system is created by bending sheet metal into a U-shape, then simply epoxy-adhering them directly to the back of the board. With the right equipment, it takes about 30 minutes to create this.
Here’s the final product:
The RPTC (top) and Forge hangboards with adhesive-mounted brackets.
Here’s how to make it….
Start with the brackets. I used galvanized steel Simpson Strong Tie framing backets, and used a “bending brake” to bend them into the desired U-shape. If you can find some, try to get brackets that are already shaped to fit over a 2×4. I picked some up at home depot, the HTP37Z. These are about $2 each, and they are a pretty heavy duty gauge (16 Gauge):
This is another option, the A44 but more expensive, at $4.50:
Here’s another option. It’s pre-formed, but it’s a thinner gauge of steel (18-Gauge), and a little smaller, so it would provide less surface area for adhesion. Most importantly; I haven’t tested it:
OK, so you have your brackets. If you need to bend the brackets, measure them carefully and account for the material that will be used up in the corners for the bend radius. I suggest buying an extra bracket in case you mess up. A bending brake is the best tool, which I have access to at the Air Force Academy’s Applied Mechanics Lab:
A simple bench-top vice will work too:
Here’s the desired shape:
You need two brackets per half of the RPTC or Forge, so four total to mount a hangboard system.
THe HTP37Z bent into shape.
This step is critical! For proper adhesion, you must prepare the surface of the steel brackets. I used a sand-blaster, but sandpaper, or a Dremel tool works too…it just takes longer. Sand the surface of the steel that will adhere to the RPTC or Forge to rough it up and remove any contaminants so that the epoxy forms a good bond. This is critical because the brackets will have a thin film of oil and other debris on them. Once you have treated the surface, don’t touch it or otherwise let it get dirty. The hangboard can be lightly sanded as well, but in my experience, simply wiping it down with a paper towel and solvent is adequate.
I used West System 105 Resin and 205 Fast Hardener, shown below, but any number of commercial adhesives will work, such as Gorilla Glue, Loctite, JB Weld, etc. The surface preparation is far more important than your choice of epoxy.
If using a 2-part epoxy (which I recommend), make sure it is mixed thoroughly. Here, I’m using a paper cup and a tongue depressor that I’ve trimmed the end off of so that it is flat and can cleanly scrape the bottom of the cup. Follow the instructions for your epoxy carefully.
Now glue the brackets on…. Take care to get proper alighment. On the Forge, the top edge should be parallel to the ground, so I used a straight edge, as shown below, to line up the brackets with the top edge of the board. This ensures the board will hang parallel to the ground. Don’t fret, if you make a mistake and the brackets are uneven, you can always add shim material afterwards to level it out.
Once the brackets are in place with epoxy, they may drift a little before the epoxy sets, so tape them down with some masking tape. If your brackets have fastener holes, like mine, cover the holes with tape so epoxy doesn’t bleed through the holes. If it does, it can impede the brackets from sliding over your 2×10 (you can sand any excess epoxy off, but it’s a pain). You want to place the brackets as close to the outside edges of the board as possible to prevent unintended rotation when using the outer holds, such as the pinches.
A “blank” 2×10 mounted in my basement, ready to accept my bracket-equipped hangboards.
Finally, let the glue dry and mount your 2×10, if not done already. Here’s an earlier article describing how to do that: How’s Your Hang? Now enjoy your adjustable mount!
If you’re skeptical and discerning like me; you may be wondering…how strong is this adhesive mount anyway? Well, since I have access to the best undergraduate mechanics laboratory in the world, and the best undergraduate students, I decided to find out. I assigned a group of cadets to investigate (Cadet Mike Hyde, Cadet Nate Dickman, and Cadet Tim Welkener). They are Mechanical Engineering students at the Air Force Academy, and this testing served as their final project for their Experimental Mechanics course (lest you think I’m abusing my powers 🙂 ). Trango donated some hangboards, and the cadets replicated the mounting system, then tested them to failure. Here are a couple pics of the testing:
Mounted boards – Note they only are using one bracket per board. This setup is not for “operational use”, only for testing. The bolted-on brackets at the bottom are used to ensure a solid connection for testing the epoxy-mounted brackets at the top of the boards.
An MTS Tensile Test machine. This was used for static strength testing and fatigue testing (repeated loading and unloading). Here they are testing an un-formed bracket (the bracket is flat) to isolate the epoxy-polyurethane bond. This is the “pure shear” test.
The RPTC with bracket mounted over a 2×4 for testing.
Close up of 2×4 mount.
The cadets did a few tests:
- Pure Shear Test – here, the brackets were flat and held in the hydraulic grips of the MTS machine. This test isolates the epoxy bond. They ran a couple variations to test different surface preparations and epoxy combinations, but found little difference that would matter to us. In these tests, a single bracket held over 3,000 lbs! Consider that you will be hanging from four brackets (two per RPTC/Forge half), and the epoxy is plenty strong!
- Cyclic Fatigue Test – In this test, the goal is to determine if repeated loading and unloading weakens the bond over time. With our MTS machine, we can apply repeated loads very quickly. They performed two variations on this test: Cycle load of 0-200 lbs for 650,000 cycles and 0-400 lbs for 75,000 cycles. The bond didn’t fail in either of these tests. I perform 24 sets of hangs on 8 grips per workout, which is 144 hangs per workout, so 75,000 cycles is the equivalent of 520 hangboard workouts, or about 52 seasons of hangboarding. I think we’re good!
- Formed Bracket Test – This test is probably the most relevant to us because it test the entire system, not just the epoxy bond. Here, the bracket is bent into the proper shape and placed over a 2×4. This was another static strength test, meaning the load was not repeated, just gradually applied until failure. The system failed when the steel brackets deformed (un-curled from their U-shape) at a load of 624 lbs. Again, this is for only one bracket — you will be hanging from four brackets.
Here’s a picture of the epoxy bond after the shear test:
…And the deformed brackets:
Here’s a of quick video one of the pure shear tests.
In conclusion, I think you can hang with confidence off your new adjustable mount!