I’ve recently seen a lot of people mentioning using washers as a good way to reduce friction, espeically for flywheels. However, Vex offers three different kinds of washers, and this season we also have the option of using any commercially available washer provided they are used for their intended purpose.
My question is: are there different applications where a particular type of washer would be most effective? For example, is one type of washer better at reducing friction against a bearing while another is better at reducing friction against a metal component?
I am not entirely sure if metal vs plastic surfaces makes a difference. The coefficient of friction should be the guiding answer. Heat build up over time can change material properties too.
Delrin is a nice plastic that is easily molded which is why vex uses it. But PTFE generally has a lower coefficient of friction.
Matweb is a good resource for looking up material properties you might consider as you peruse various catalogs.
PTFE is the typical go to material for low friction but can be a bit expensive. But luckily PTFE washers are not that expensive compared to sheets of it.
We have high RPM cases this year with Nothing But Net flywheels where it may get too hot of an operating range. Not entirely sure how it will play out.
While I haven’t done any accurate comparisons, I find that there is a difference in the friction of the PTFE and Steel washers, although nothing very major. I also like the fact that the PTFE washers are a bit thicker, and unlike the steel ones have a consistent thickness, which makes them easier to work with.
I haven’t tried out too many different types, but I have some nylon ones that I find are virtually the same as the PTFE ones, but nylon is a significantly cheaper material.
Edit: I just tried the two types out, and I find there isn’t any noticeable difference between PTFE and Nylon, and VEX’s white spacers are made of nylon too and they are pretty low friction.