The composition and microstructure of the stainless steel can also impact friction, as different grades of stainless steel may have different frictional properties.

With the components completely submerged, I generally use this time to wipe down the bottom of the board (just the board; do not wipe down the trucks or axles) and the wheels. Please note that this is a very messy job so your hands will get disgusting (also, don't wear white).

One simple way of determining the static coefficient of friction for materials is by measuring the largest angle of inclination before sliding.

Static friction is the resistance to initiate sliding—it is generally greater than that required to sustain dynamic friction. If the applied force exceeds the maximum static friction force, however, the object will start to move, and the force of friction will decrease to a lower value (dynamic friction). The maximum static friction force depends on the nature of the surfaces in contact and the normal force pressing them together.

After sliding initiates, the frictional force, Fr, typically drops to a lower resistance value, F. The coefficient of sliding friction, f, is commonly expressed as F=N f.

Results from a different FOF test configuration, comparing the sliding coefficients of friction for coated and bare stainless steels, show that the two harder grades of stainless steel (17-4 PH and 440C) had slightly lower coefficient of friction values, compared to type 316. The use of Teflon and ME-92® coating reduced friction of bare stainless steels. Remember that these numbers are only initial friction values. During actual use, the friction of bare stainless steels can increase unexpectedly due to wear and particle generation. This was demonstrated by the results of the pin-on-disk wear test results presented earlier.

Not all bearings are created equal! I tend to buy bearings based on their ability to be cleaned which is why I bias myself towards bearings like the Bones Super Swiss 6 bearings (which is what is pictured above). I have tried other sets (in fact I just bought a pair of Heady Shake Pro bearings which a friend highly recommended), but for the money and quality, I am a Super Swiss 6 rider for life.

Now, we’re going to shift our focus to reducing friction. We’ll provide an overview of the two classes of friction and explain why knowing the initial friction value is not enough to make an adequate materials selection for medical devices. We’ll also describe test methods and standards for determining friction and provide a list of design considerations for reducing friction in medical applications.

How to clean a skateboardwheels

With all of the components in the glass jar, pour just enough alcohol into the jar so that they are completely submerged. Seal the jar and give it a good shake. I typically leave the components in the jar as long as it takes me to wipe down the wheels and board (approximately five to ten minutes). As you can see from the pictures above, the alcohol does a bang up job cleaning the components.

This is pretty much self-explanatory. Basically the first step is to take the wheels off the board and disassemble them. Make sure not to lose any of the nuts, washers or spacers as those should be cleaned as well. As such, when you do take the nuts, washers and spacers off, put them into the glass jar. We'll deal with the bearings next.

How to clean skateboardwheels and bearings

With regards to "play" or "give" in how loose you ride your wheels, that's really a personal preference. Obviously too loose and the wheels will fall off, so don't do that. Personally I like just a little bit of play but not much. You can see from the photo above where I finally have my nut.

Coefficients of friction depend on both mating materials. Friction can vary greatly when one of the mating materials is changed. Reducing friction coefficients reduces the force required to operate an instrument. This translates into easier instrument operation and greater operator sensitivity.

Increasing the contact load may cause an initial increase in friction. This is different from what we’ve been taught about friction. This increase in friction is related to changes on the contact surfaces. Increasing the sliding velocity can increase the operating temperature. This usually increases friction. However, if one of the two surfaces liquefy as a result of heating, friction may decrease.

Various modifications are in use to change the surface properties of stainless steels. Coatings are sought for reducing friction, lowering wear rates, reducing galling, and providing easy release, and nonstick properties.

In addition, the presence of contaminants can lead to the formation of corrosion or other chemical reactions, which can cause surface pitting, roughness, and increased adhesion.

In a pin-on-disk test for three different material configurations, wear was practically non-existent with samples using ME-92 coating compared to bare 17-4 PH. This test not only gives wear information, however, but computerized systems can constantly monitor and plot friction values.

How to clean skateboardtrucks

To disassemble the bearings with the rubber shields, the easiest thing to do is to take either a SIM extractor tool or a few staples straightened out and push gently through the bearing in-between the balls (NOTE: you should not have to push hard. If you find that you are pushing hard, you're doing it wrong and you may damage the bearings).

In conclusion, surface conditions are critical when measuring friction. Friction is sensitive to many factors, such as atmospheric dust and humidity, oxide films, surface finish, sliding velocity, load, temperature, vibration, surface contamination, and lubrication.

When there is a lack of adequate lubrication, the two surfaces can come into direct contact with each other, and the roughness and asperities of the surfaces can interlock, causing resistance to motion.

We characterize friction as either static friction or dynamic friction (also known as kinetic or sliding friction) and express it as static and dynamic coefficients.

Stainless steel surfaces may have microscopic irregularities. This excessive surface roughness generally increases friction between unlubricated and lubricated materials. Note that the shape of the surface asperities is important; surfaces with the same average arithmetic surface finish may have very different surface profiles. The profile may be like rolling hills or a saw tooth shape. More jagged profiles increase friction by biting into the mating material.

How to clean a skateboardwith household items

Even though the initial frictional values for the three configurations were very similar, friction for the bare 17-4 PH significantly increased as the testing continued. The most consistent frictional values were obtainable when both components were coated with ME-92® — neither wear nor particle generation was detectable.

This is where my instructions tend to diverge from the instructions that come with the lubricant, and there's a very good reason for that! The cost of the lubricant is only about $5 and even if you over lubricate your components, you'll have that one little bottle for at least six months. Generally speaking, my process is as follows:

How to clean skateboardwheels without removing them

An elevated or change in temperature can cause metal surfaces to expand, which can cause them to come into closer contact with each other, leading to increased friction. In addition, variations in temperatures can cause changes in the physical and chemical properties of materials, such as increased surface roughness, reduced ductility, and increased hardness. These changes can cause the surfaces to interlock more closely. In some cases, high temperatures can also cause the lubricant to break down or evaporate, leading to direct contact.

This demonstrates that the initial friction measurement alone is not a sufficient design criterion. One must consider how friction varies with time, for moving assemblies, to obtain desirable performance in the field for reducing friction.

Friction is the resistance one encounters when sliding or attempting to slide two surfaces. Whether or not friction occurs in medical-grade stainless steel depends on a variety of interrelated factors:

In the inclined plane test, a block of one material is placed upon a flat surface, which is slowly inclined until block sliding occurs. The resultant force (R) is equal and opposite to the force (P) of the sliding body. The resultant force can be resolved into a normal component (N) and a frictional component (Fr), which resists sliding. The coefficient of static friction is given by the following equation:  f 0 = tan ao, where ao is the angle of rest or repose just before sliding.

How to clean a skateboardgrip

What I'm about to describe is not my own creation. Rather, it's a patchwork of suggestions and solutions that I received from both friends and online resources. Unfortunately, there are just too many to name specifically so for all of you who have ever created a blog, a video or a discussion on the topic of bearing maintenance prior to me publishing this, thank you! Your work inspired me to keep my hardware clean and my wheels spinning!

Lastly, with everything in place, give the wheel a solid spin and sit back to enjoy your efforts! Better yet, hop on your board and ride!

Much research had been done in the past to characterize friction between similar metals and various couples. Results vary greatly depending on test configuration and conditions. It’s therefore necessary that only frictional results collected under the same or similar circumstances be compared.

In our previous medical device design discussions, we explained methods to reduce wear in stainless steel, and how utilizing thin dense chrome protective coatings during the design phase can extend the life of your applications.

When I first started riding to work regularly I found that my board would get quite dirty, especially since I work in San Francisco (those of you who live or work here know what I mean). In order to make sure that I properly maintained my longboard I started researching online for methods and best practices. This instructable is a culmination of my findings.

If after reading this you have a different suggestion or a step that you'd tweak, I'd love to hear from you! As I mentioned when I first wrote this, I learned this process from many other sources so it can only help other readers if we share our "secret sauce" for bearing maintenance. Please do post questions and comments and I'll be happy to respond.

I also put a little bit of the lubricant on the spacer (this is why I mentioned not to clean the axles; the residual lubricant helps). I basically put the tip of the bottle at the top, squeeze slightly and rotate the bottle around the circumference of the spacer

It is helpful if the operating conditions maintain an oxide film on the sliding surfaces. Some materials perform poorly in environments that lack oxygen. Special consideration must be given to systems operating under inert gases, reducing environments, or vacuum.

As previously discussed, excessive surface roughness can increase friction between unlubricated materials. Polishing of surfaces can help reduce friction. The friction of bearings often lowers during use from a mutual polishing that takes place, assuming prior removal of wear debris.

When we talk about friction, we mean resistance to movement. Initial friction is not usually the important number; rather, will the friction remain constant throughout an instrument’s use?

For medical applications, it’s also necessary that coatings be nonreactive to the body—one of many benefits ME-92® biocompatible chromium coating provides. Let our metallurgical and materials consulting, research, and testing experts help you extend the life of your medical devices.

Many devices are useful to measure the necessary force to initiate or sustain sliding. Both sliding and rotational setups are in common use.

Grip gum

How to clean skateboardbearings

Typically I will clean my bearings once every four to six weeks, depending upon usage. I have definitely noticed a difference in speed and smoothness of my ride when the bearings are clean (I liken it to the feeling you notice when you just had your oil changed in your vehicle). Either way, a routine cleaning will help to maintain the longevity of your skateboard or longboard and allow it to perform at its best.

Pressure can also cause increased deformation and adhesion, changes in lubrication properties, and changes in the contact area between the surfaces.

There are several types of lubricants used for reducing friction. Graphite, molydisulfate, PTFE, and ME-92® coating are examples of dry lubricants. Molydisulfide performs excellently under vacuum conditions, while graphite can become abrasive under the same conditions. Various water-soluble and oil-soluble liquid lubricants are also available. The operating parameters and biocompatibility of solids and liquids must also be considered for each application.

Defined as the ratio of the sliding force to the total force pressing the two surfaces together, the coefficient of friction, f , is one of the general physical properties of a material. We describe coefficient of friction by the formula: f =F/N, where f is the coefficient of friction, F is the force to initiate sliding, and N is the total (normal) force between the two surfaces.

The presence of surface contamination may either increase or lower friction. Results of the pin-on-disk test, presented earlier, showed an eightfold increase in friction on bare 17-4 PH due to particle generation. Some films, such as body oils, can act as lubricants. Oils picked up during handling, however, can accelerate surface corrosion.

It’s important to know what type of sliding is taking place (rotational, translation, etc.) and which material is the moving member. Friction can change depending on which of the two surfaces is the sliding member. For example, Teflon sliding on titanium alloy has a static friction coefficient of 0.17, while titanium alloy sliding on Teflon has a value of 0.2300. This type of information is not usually disclosed or known. Unlubricated assemblies are especially sensitive to test configuration.

One commonly used configuration is referred to as FOF (flat surface sliding on a flat surface), which compares the unlubricated frictional coefficients of various medical materials and coatings sliding on Teflon. The chromium composition coating had the lowest frictional values of the four metallic and ceramic materials listed. These results indicate that the friction of ME-92® sliding on Teflon is comparable to Teflon sliding on Teflon. Friction increased for all the materials when Teflon became the moving specimen; coefficients of friction depend on both mating materials and which material is used for the moving component.

Now that the components have sufficiently soaked, it's time to empty the jar and dry the components off. Make sure not to lose any of the small pieces as you pour out the dirty alcohol (nothing sucks more than having to buy a new set of bearings because you lost just one or two rubber seals).

ME-92® consultants at the Armoloy Innovation Center in Dekalb, IL are available to assist clients in establishing how each factor affects a particular assembly. Furthermore, to make a proper selection, each material couple should be evaluated with the following variables in mind:

Dust, wear particles, and debris tend to increase resistance to sliding. Moreover, the size, shape, and hardness of the contaminant particles can affect the severity of the frictional effects.