The most important consideration when looking at replacing conveyor rollers is making sure the roller is measured properly. Though rollers have standard measurements, they can vary from manufacturer to manufacturer.
Therefore, knowing how to properly measure your conveyor roller, as well as which measurements to take, will insure that the conveyor roller will fit properly and that your machine will run smoothly.
For standard conveyor rollers there are 3 key dimensions to have:
- The between frame – or overall cone – dimension
- The diameter of the roller
- The axle diameter and length
Tube length is not an accurate way to measure the length of a roller because it is dependent on how far the bearings extend from the tube and will change with the different bearings being used.
Ready to go? Grab these tools for proper and accurate measurement:
- Tape measure
Measuring Between Frame
Measuring Between Frame (BF) is the distance between the side frames of a conveyor and it is the preferred dimension. It is sometimes referred to as between rail, inner rail or inner frame.
Anytime you are measuring a roller, it is always best to take the measurements off of the frame since the frame is a static reference point. By doing this you do not need to know the manufacture of the roller itself.
Use the tape measure to measure the distance between the two side frames to get the BF and measure to the nearest 1/32″.
Measuring Overall Cone
There are some instances, such as a deep frame, the way the rollers are set, or if you have the roller sitting in front of you, where the OAC is a better measurement.
The Overall Cone (OAC) is the distance between the two outermost bearing extensions.
To get the OAC, place the angles against the cone of the bearings — the very outside of the bearing. Then, use the tape measure to measure between the angles. Measure to the nearest 1/32″.
Add 1/8″ to the total OAC to get the Between Frame width (BF), if it is not specified by the customer.
Some situations when this should not be done include:
- Rollers with welded axles. They do not have an OAC.
- If bearings are missing from the roller an accurate OAC cannot be measured. Make note which bearing(s) are missing.
- If one bearing is good, measure from the edge of the tube to where the bearing meets the axle (the very outside of the bearing) and add it to the other side for an approximate measurement.
Measuring Tube Outer Diameter (OD)
The calipers are the best tool for measuring tube outer diameter. With your calipers, measure to the nearest .001″. For larger tubes, place the neck of the calipers close to the axle with the forks swung at an angle out over the tube.
Measuring Axle Length
To measure axle length, place the angles against the ends of the axle and use the tape measure to measure between the angles. Measure to the nearest 1/32″.
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