Whilst most people take no notice of copper split bearing units, they actually have plenty of applications. Mounted on a shaft, the split bearings snap together the same way a faucet tip does, creating a smooth surface as we have no rolling elements but rather an abs (a thermo-polymer) and a small film of liquid.

The cost of a split bearing is tremendously cheaper than a traditional ball bearing or sleeve bearing. For shafts that have moderate rotations and are not heavily loaded, bronze split bearings are sassy (threading on the shaft and a bronze tip inserted) and cost saving.

This specific bearing even tolerates a dirty environment better! Most dirt and debris that destroys or even damages sealed bearings gets embedded in the softer bronze split and can be flushed away with the liquid. This is the main reason as to why they are popular in mechanized agricultural and construction equipment as it becomes difficult to maintain a clean. We have many customer that have survived an insane amount of time where woven ball bearings have lasted a couple of months.

Shock loads are something else they deal with quite well. With the bronze, instead of the impact being transmitted through hard steel balls, the bronze absorbs it. This is useful in hammers, presses, or any instance where there may be sudden starts and stops.

What You’re Actually Getting

Most of what we have in stock is phosphor bronze. This is a decent general-purpose and fair bronze, with a reasonable amount of strength and use resistance. While aluminum bronze is also a part of that stock, it is more commonly used in a corrosive environment or a marine environment (the standard bronze would corrode).

When it comes to the more inexpensive units, they may use brass instead of bronze. This may work, however, they simply do not have the same length in service life. If there is an issue with cost and you are working with very light loads, this would suffice.

There are sintered bronze bushings. These are porous and contain an oil that will eventually need to be replaced. While they are also used to self-lubricate, they will still need oil eventually and they will also be better equipped to handle intermittent use than solid bronze bushings.

The Lubrication Thing

This is a requirement. Without oil, there is no bushings, and without bushings there is simply metal on metal. This means that friction, heat, and wear will all increase and eventually, it will wear everything out. Some systems have continuous oil feeds from a pump, while others will simply need to be greased. How much she gets worked, depends on what she gets.

When regular lubrication is not an option, such as when it is difficult to do or no one will do it, you should consider using sealed ball bearings. Although they are more expensive initially, they will not seize after six months of use.

Fitting Them Correctly

The distance or space between the shaft and the bush affects the proper functioning of the system. We receive calls from customers that experience bushings that are not functioning properly or that are running too hot due to insufficient distance. If the distance is too small or too tight, the system will overheat. If the distance is too large, too loose, or too little, excessive movement or play, will cause excessive and rapid wear.

The finish on the shaft is also important. A rough surface on the shaft wears the bronze material quickly. If you are machining the shafts to your own specifications, you should be aiming for a surface that is decent to moderate or better.

Bushings will wear unevenly due to a lack of alignment, just as bearings do.

When They’re Not the Best Choice

Bushings are more of a problem for higher speeds. Unlike ball bearings, bronze bushings will create more friction, which means more heat. If the speed is high enough, the heat will not be able to be dissipated quickly and there will be a lot of problems.

Plain bearings are also not appropriate for most precision applications. Best control for minimal play and tight running clearances is with ball bearings.

Also, do not use them when lubrication is difficult or unreliable. Sealed grease ball bearings can run for years without maintenance while bronze bushings cannot.

The Split Design Advantage

Overall, the split design is a big installation improvement over solid bushings. There is no need to dismantle the entire assembly or slide the bush over shaft length; just bolt the two halves around the shaft. It also makes replacement easier, and that is a notable improvement when you are dealing with worn bushings on existing equipment.

When suited for the application, they excel with moderate speeds, reasonable loads, contaminated situations, and where cost is a factor. If you keep them lubricated, they will provide reliable use for years, just don’t have the expectations for them that you would have for ball bearings.