Benefits Of M6 Wakeboard Binding Inserts: Making Bindings Secure

Are you using M6 Wakeboard Binding Inserts and bolts to keep your bindings secure? The wakeboard industry has gone through a lot of changes in its development of boards and wakeboard bindings. The results have been more secure wakeboard boot / binding inserts.

The wakeboard industry has been working towards common standards which decrease the cost of manufacturing while allowing products to be interchangeable across brands. This helps wakeboarding grow. More specifically, we’ll explain the decision to move to M6 wakeboard binding inserts. The outcome is less hassle for you, the buyer.

Much like the wakeboard industry, the snowboard industry has gone through similar changes with insert and binding patterns. The skateboard industry has gone through it with skateboard trucks.  The surf industry has gone through it with fins.

What existed before the invention of wakeboard binding insert threads?

In the early days of wakeboarding, we saw wide 8 inch wide binding plates [called a chassis]. As wakeboard bindings evolved and materials, innovations, and assemblies were modified, they moved to 7 inch plates. Then again more recently, wakeboarding moved to 6 inch plates. This drastically reduced the amount of chassis material for the boot. This lightened up the weight of your binding.

In as similar vein, we’ve also seen many companies evolve with fin screws and fin hole spacing.  They’ve gone from one single fin hole. Then they moved to two fin holes spaced 1.5 inches apart. Finally settling on a 3 inch hole standard with 1.5 inches spacing between each fin hole. This makes swapping fins across boards or finding replacement fins much easier. 3 inch hole standard for fin inserts are what we use at Humanoid Wakeboards.

Early growth of wakeboard binding insert threads

The most recent change has been in regards to wakeboard binding insert threads. Since I can remember, wakeboard binding insert threads have been quarter-twenty (1/4-20) threads, which are a UTS (Unified Thread Standard) measurement popular in the US and Canada. It’s probable that this thread standard was chosen for wakeboards since wakeboarding originated in the US. Over the years,  wakeboarding has grown to be a more global board sport along with surf, skate and snowboarding. The ISO (International Organization for Standardization) metric thread popularity and availability has influenced manufacturers to change from  Standard threads to Metric threads. Let me explain why this decision is a better suited option for wakeboards.

Metric and Standard wakeboard binding insert threads

The first major reason for the binding insert update is availability. The snowboard industry is much bigger than the wakeboard industry. Snowboard manufacturers use the same board inserts on snowboards. Snowboarding moved to a metric standard years ago for the same reasons wakeboarding is doing it now. Since snow brands are a larger market, they have more manufacturers producing inserts for snowboards worldwide. This makes metric inserts more readily available and cheaper for manufacturers to purchase in the wakeboard industry. This is a major reason to switch. More availability and cross compatibility. Now onto the performance benefits.

The Performance Comparison between M6 Wakeboard Binding Insert Thread and 1/4-20 Standard Thread

Now lets talk about the performance difference between M6 Metric and 1/4-20 standard threads and why the decision to switch benefits you. We are only going to compare these two wakeboard binding insert threads since they are the main ones used in the market today. Insert depths from manufacturer to manufacturer do vary, but on average inserts are at least 10mm deep. So this gives you at least 10mm of thread engagement if your binding bolts penetrate at least 10mm into your wakeboard. Here’s where you start to see the real difference.

On a 1 inch 1/4-20 binding bolt with standard threads, the first 10mm of the bolt only yields 9 full threads.  A one inch M6 bolt with metric threads yields 12 full threads. Yes, a small difference but these 3 thread guarantee you a more secure fit. This is a ‘perfect world’ example.So I decided to consult one of our engineer friends Kevin Kimball. Here’s what he had to say…

From the engineer

Thread Failure

“I did a few quick calcs to see what the differences are for the 1/4-20 and M6 bolt thread engagement. Let me start by saying a couple things. First, threads fail progressively meaning they don’t all fail at once. When a screw fails the first thread fails first, then the next , then so on and so forth up the shaft of the screw. It just happens so quickly that it seems like they all fail at once. With that in mind, you also have to plan for the first thread or so of the screw and the first thread of the insert having flaws as part of the machining process, so we’ll need extra threads to compensate for these first weaker threads.

Minimum Thread Engagement

The typical desired minimum thread engagement depth for any screw size is usually 1.5 times the diameter of the screw. So this means a M6 metric screw with a diameter of 6mm has a minimum thread depth requirement of 9mm (6mm x 1.5). A 1/4-20 standard screw has a diameter of 6.35mm, so it has a minimum thread depth requirement of 9.525 (6.35 x 1.5). So both screw types have a similar required depth but 1/4-20 standard screw has less threads in this distance because standard threads are more course. This may be a reason so many riders are have problems with the screws getting loose. There are not enough threads on a 1/4-20 screw working to hold the screw in place.

Thread Pitch

As thread pitch moves from course to fine, the slope in the fit goes down. When making a courser 1/4-20 threaded hole, the actual % thread is about 55%-60%. That means the hole drilled in the insert is sized so that the tap only uses the outer 55-60% of the tap teeth to cut threads. Threads are not full depth and therefore, are more loose. This is done because it is difficult to make 100% threads with course pitches.

As you move to a more fine thread pitch like the M6, the % thread is more like 75% so 3/4 of each thread face is in contact between the screw and the insert. The fit of the M6 has less slope and tends to better stay in the tight condition as compared to a course thread. A fine pitch thread tends to stay in place better than a course thread since the % of change per rev is less for the fine thread.

What does this mean for M6 vs. 1/4-20 screws?

Simple. The choice of M6 bolts for the boards will provide a more secure fit of the bolts to the inserts. This will improve the bolt retention and be better for keeping the binding hardware locked down. This improved fit comes from having more threads engaged between the bolts and inserts as well as the better machining of the insert threads associated with the M6 size compared to the 1/4-20 screw.”

— Kevin Kimball
Engineer

The angle of threads in binding screws

To go along with everything mentioned above, the angle of the threads, referred to as lead, are steeper on the 1/4-20 standard screw than that of the M6 metric screw because the M6 has more threads packed into the same distance. Since M6 has a shallower [less steep] angle, it has less chance of wanting to slide along that angle and loosen. If you thought of the threads as a slide, which threads would you be able to slide down easiest, up or down? The answer is the 1/4-20 standard screw, which means they have a greater tendency to loosen when compared to the M6.

Safety First. Tighten those bolts!

Now that you understand why metric threads are better from an engineering stand point, let’s talk about how to properly tighten screws when assembling your board. First, the most important thing to remember is that you should always check your binding screws before every ride, no questions asked. Every ride. They always have the potential to loosen regardless of the type, M6 or 1/4-20.

If you ride with loose screws your bindings can skip teeth, which can twist your knee, ankle or leg in general when you land. This quick change of your stance angles can cause injuries. It’s smart to keep screw drivers in your boat or vehicle if you travel to the cable park. Most cable parks have tool tables or tools available there, but don’t count on that. Also, most of these tools available at the park are usually pretty beat up from regular use, so you are better off bringing your own screw driver. Make sure it’s the proper type of screw driver. What’s the proper type you ask?

Get the right tool for the job. Use the right screw driver for M6 binding inserts.

Most people have seen different size screw drivers, but don’t really pay attention to the actual sizing needed for the screw they are using. They just grab the nearest screwdriver and crank away. What they don’t realize is that each size screw head has an ideal corresponding screw driver size requirement to achieve proper grip.  It also stands to decrease wear on the screw head while tightening. More simply put, the proper screw driver will allow you to get your wakeboard binding screws tighter and the screw heads will last longer. Most manufacturers like us supply you with “Phillips” head screws, so the screw drivers we will be talking about are Phillips screw driver.

See the chart to the right. Our M6 binding inserts screws size sits in the 10-16 range on the chart. This requires a #3 size screw driver, which is pretty large. If you use a smaller size screw driver on our M6 screws or even on 1/4-20 wakeboard bindings screws you can quickly wear down the head.

Using the wrong tool increases wear [and don’t use a drill]

Check out the image below to view three M6 heads of the same size, the first tightened with a screw driver that was two sizes too small (#1), the second tightened with a screw driver that was one size too small (#2) and the third tightened with the proper #3 size Phillips head screw driver.

You can really see the difference in wear on the heads. More importantly, you feel the difference in how much tighter you can tighten the screw using the proper #3 size screw driver. I was able to to get almost another full 360 degree turn out of the proper combination and this means that my bindings are tighter to the board resulting in a safer assembly. And remember, drills have a tendency to cause even more damage to the screw threads along with the top shown below. A drill will also heat up from friction that causes irreplaceable permanent damage to the board insert & screw head.

The performance benefits of the right tool. More response!

So how does this all translate to your wakeboarding performance benefits? Heel lift in your bindings causes a slower board response. Heel lift is when the wakeboard binding chassis bends when making a turn. The less heel lift, the more response you get from your wakeboard & wakeboard boots.

Decreasing heel lift poses a challenge for most manufacturers since we are limited to only one central row of inserts on the board. So it’s important to max out the performance and strength of M6 inserts, screws and wakeboard bindings. Next time you grab your wakeboard to take a set, make sure you grab the proper #3 screw driver. Crank your screws down tight for a better response while keeping yourself safe.

Now you know! Having trouble knowing how to choose your M6 equipped wakeboard? Check out our shop and see what works best with your riding style — or customize one of your own! Need more help deciding? Learn more about how to buy a wakeboard, why we like Flex wakeboards, how to choose your size, or even how to edge better. Happy hunting!