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Senior Contributor

## Angle of repose

I was trying to figure out how many beans I have in my bin.  it is piled up.  To figure the volume of grain that is piled up, one needs to know the angle of repose.  That is the angle that the grain makes if you let it pile up naturally.

Crop                  (degrees)             Tangent
Barley                   28                         0.53
Shelled corn       23                         0.42
Oats                     28                          0.53
Soybeans          25                            0.47
Sunflowers        27                         0.51
Wheat                25                          0.47

4 Replies

## Re: Angle of repose

the angle of repose depends on how dry the grain is. the drier the grain the flatter or less angle there is.

as I  recall the volume of a cone is the area of the base times 1/3 the cone height.  the angle is not a factor when calculated this way.

Senior Contributor

## Re: Angle of repose

You are right that the angle of repose depends on moisture.  The figures given were for standard moisture for each grain.  As you say, if one knows the height, the angle is not needed.  When one does not know the height of a cone and has no other reference, knowing the angle of repose allows one to calculate the height when needed.

Veteran Contributor

## Re: Angle of repose

I worked as a field reporter for the local county ASCS office back in the 80's. I was in almost every bin in the county then, plus some in neighboring counties.  The formula we used for cones was the diameter squared times .262 times the height of the cone, giving cubic feet which we then converted to bushels.  Sometimes we had to do some "mental pushing" if the grain was piled unevenly.  Sometimes the height of the cone had to be estimated.  We also used the same formula for inverted cones where grain had been drawn out of a bin, subtracting the volume instead of adding it.

One of my biggest challenges was from a farmer who moved reserve corn from a bin on one farm to a quonset on another farm.  Enroute, he took it all to town and weighed it before piling it in the quonset.  I needed to be sure he had enough grain in the quonset to cover his reserve contract.  He knew how much corn he'd weighed and put in there and wanted to see how close I came.  It took more than one trip to the quonset to get measurements.  When I was done I came within about a hundred bushels of what he said he'd put in.

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## Re: Angle of repose

@NYnotiller wrote:

the angle of repose depends on how dry the grain is. the drier the grain the flatter or less angle there is.

as I  recall the volume of a cone is the area of the base times 1/3 the cone height.  the angle is not a factor when calculated this way.