Why is my shaft collar oval?

Shaft collars have a million uses – and yet you may never have heard of them. As wonderful as we think they are, often a slightly oval shaped collar is confused with a bad part when that is most assuredly not the case.

Shaft collar 101

Let’s start with the basics – what is a shaft collar? A shaft collar is an often essential component in machinery. They almost look like rings and are designed to fit around a shaft – typically cylindrical- to secure, position and space components on a shaft. Often manufactured using stainless steel or other strong material, they are designed with security in mind.

There are three main types of shaft collars:

Set collar

A set collar, sometimes known as set screw collars, are simple, one piece shaft collars. They look almost like a donut with a set screw so that they can be tightened onto the shaft.

Single split collar

A single split collar is a type of collar that is designed to provide a secure grip on a shaft without causing any damage. Unlike a set collar, the a single split collar is used to clamp tightly around the shaft rather than screwing to it. The set screw is placed through the walls of the collar to effectively clamp it.

Double split collar

A double split collar is made up of two pieces. Similar to the single split collar, it is designed to provide a secure grip on a shaft without causing damage. As it comes in two parts, it is easy to install and remove.

A double split collar, also known as a two-piece clamping collar, is a type of shaft collar designed to provide a secure grip on a shaft without causing damage. It consists of two halves that can be completely separated, making it easier to install and remove, especially in applications where the shaft cannot be easily accessed from the ends.

Are oval shaft collars less secure?

Shaft collars come in an incredibly wide range of sizes to fit many shafts. This is known as the Inside Dimension (ID), it allows you to select the right shaft collar to fit the diameter of your shaft.

As a set collar is a solid ring, it is perfectly round.

Similarly, with a single split collar, it is mostly a solid ring. However, a saw has been used to cut a slit into the side of the ring to allow for tightening. This means that before it is tightened, the centre of the collar is completely round.

However, a double split collar can often be confused with being oval in shape. This simply comes from the fact that when the saw has cut through the metal on both sides of the collar, it has lost a minute amount of material. This means that when it is fully tightened onto a shaft, due to the missing material, it is not completely round. In a larger shaft collar the missing width of the saw will barely be noticeable, but it may appear ovular in a smaller collar. That’s not to say that if it isn’t round it isn’t secure, it is, and will still fit the shaft that the ID was designed to fit.

So, if your double split shaft collar appears to be a little oval, there’s no need to panic, it will still fit just as well as a one piece collar would, if not better.

View our range of shaft collars here.