A flange bushing will prevent two piece of hardware from grinding on each other when a rotating shaft needs to be housed yet kept in place along its length. A flange bushing has the advantage that it is both a stop for axial movement as well as the bearing surface all at once.
Finding the correct size is necessary but the choices expand rapidy, so having a good idea what size you are looking for helps. The chart above details the bore sizes ranging from a quarter inch to three inches in common sizes. These is paired with the outside diameter, flange size, length and material of that bore. The chart also details the load rating of this combination.
How to Choose the Right Flange Bushing
Down the column of bores, you can determine the size of the shaft you have and then know what is needed and which material fit the workload of the housing. This takes out the guess work and helps you decide if a nylon bushing will do the job or if you’re going to need steel or bronze.
Maintenance
This is considered a trade-off between load, heat, and frequency of maintenance. For all things industrial, bronze does well as it can carries decent loads and self-lubricates out off the pores. Steel is better at handling heavier shock and temperature but needs outside grease or oil. Nylon costs less and is lighter in the case of reasonable demand and a clean environment. PTFE resists chemical attack and high temps. Cast iron offers wear resistance and compressive strength where speed are not critical.
These options is compared head-to-head here so that you don’t go for the default (whatever’s on hand) but rather choose based off the working environment. Is the bushing removable after? Or is it there forever? This depends on what kind of fit you are using. If you need the bushing to never move at all, then you will want to have a press fit that lock the bushing into place with a tiny bit of interference.
If you need to remove the bushing frequently or just use this as a prototype, then you’ll want a slip fit that goes in by hand, but also comes back out by hand. Finally, if you don’t mind some wiggle but still need a good way to keep the bushing in place, you’d go with a clearance fit. This provide enough space for the bushing to slide around inside, but not enough to fall out.
How loose or tight should your fit be? That answer depend on each of the above options. In the fit section you can see exactly how much gap you want to allow between your bore/housing and your bushing’s outer diameter.
The same applies with lubrication. For self-lubricating materials such as PTFE or bronze, there is nothing further to do once installed. For higher speed and load applications, you can provides your own by adding lubricants through oil holes or via grease grooves. If it gets hot enough that conventional grease doesn’t work, go with graphite plugs or use a Zerk fitting if you can get at the bushing from time to time.
You should of checked this first. These products include automotive suspension, food grade machines, pivot pins, and conveyor rollers. All of them use a barrel that supports a shaft while keeping the bushing from sliding out of the housing. With the proper combination you’ll get maximum life out of the bushing that matches or exceeds the life of the machine. It doesn’t become the first thing to go.
Know your load, know your shaft size, know how much maintenance you want to do on this bushing and know what temperatures it will be exposed to. That tell you the chart numbers. Which one do you need to keep it running? Which material? What fit level? All those decisions is up to you.
