ATTACHMENT SOLUTIONS FOR LIGHT AND HEAVY EQUIPMENT
GLOBAL DEMANDS, SMART SOLUTIONS
CUSTOMER SUPPORT - Technical Data
Estimating Bucket Capacity

Volume = Cross Sectional Area x Length

We all know that the volume is calculated by multiplying Width x Height x Length or Area of the end x Length. But what if the area is not a simple geometric shape, or in the case of Heavy Equipment Buckets, how do you define the shape for the volume to be calculated?

The total amount of material carried by a bucket is the amount inside the bucket plus the amount piled on top of it. This is called the Heaped or Rated Capacity. The amount of material piled on top of the bucket, (heap), is determined by the angle of repose of the material being handled. The Society for Automotive Engineers, SAE, for purposes of creating a standard for comparatively rating buckets, has defined two different angles of repose:
• Wheel Loader Buckets; 2:1
• Hydraulic Excavator Buckets; 1:1
Of course, if Actual Capacity is being calculated for a specific bucket to handle a specific material for which an actual angle of repose is known, then the actual angle of repose is substituted.

Calculating the capacity of odd shaped objects was not an easy task before the use of computers and CAD drafting came into common use. The formal method involved breaking the shape down into geometric shapes, calculating the area of each them and adding all the areas together for the total cross sectional area. Alternately, a planimeter was used to directly measure it.

Today, if sufficient information is available to duplicate the shape with a computer CAD program, the area of any shape can be accurately calculated in a few seconds. Our Field Worksheet, "Measuring Wheel Loader Buckets" is an example of the detail needed to define a shape so that an accurate capacity can be calculated. Buckets for Hydraulic Excavators require similar information but we have not yet published a field worksheet.

Below is a 6 step graphical method for estimating the Heaped or Rated capacity of buckets. It approximates the results that would be obtained by using the more formal methods CWS uses as outlined in:
• RATING BUCKETS - Wheel Loaders
• RATING BUCKETS - Hydraulic Excavators
Six Steps to Estimating Bucket Capacity