How to work out m3 of a round log.

[Celtictimber]

Hi There

 

As above which do you find is the best way / calculation of working out the cubic meterage of a round log as it is from a buyers point if view.

[WeeDee]

Hi There

 

As above which do you find is the best way / calculation of working out the cubic meterage of a round log as it is from a buyers point if view.

 

If the log's on its side;

 

3.14 X radius squared (m) X length (m) = volume (cubic metres)

 

then lose some volume because of the kerf.

[Big J]

You could do a 'hoppus metre' calculation:

 

Say you have a log 3m x 1m diameter. Mid girth is 3.142m.

 

3.142 / 4 = 0.79

0.79 x 0.79 = 0.6241

0.6241 x 3 = 1.8723 hoppus cubic metres in the log, as opposed to 2.3565 actual cubic metres (hoppus volume 79.45% of actual volume).

 

Jonathan

[wisewood]

If the log's on its side;

 

3.14 X radius squared (m) X length (m) = volume (cubic metres)

 

then lose some volume because of the kerf.

 

Can you elaborate please? My head is not working tonight.

Can you give us an example of working this out on a hypothetical log please?

[Daniël Bos]

Can you elaborate please? My head is not working tonight.

Can you give us an example of working this out on a hypothetical log please?

 

J's log above:

 

Pi x r squared gives 3.141 x .25 (.50 x .50) =0.785 which is the surface area.

Volume is surface (0.785) x length (3m) =2.355m2

[Celtictimber]

Ok I think I've got it lets just say for this I have a log 1.5m diameter x 4m long. What do you work the total m3 of that log is?

[WeeDee]

Can you elaborate please? My head is not working tonight.

Can you give us an example of working this out on a hypothetical log please?

 

You have a log 750mm in diameter (so radius is 375mm) and 2m in length.

 

Applying the formula you get;

 

3.14 X (0.375 X 0.375) X 2

 

which is the same as

 

3.14 X 0.141 X 2 = 0.885 cubic metres approx.

 

then you lose volume from the cuts.

 

I'd be interested to see how this formula compares to Jonathan's hoppus volume.

[WeeDee]

Ok I think I've got it lets just say for this I have a log 1.5m diameter x 4m long. What do you work the total m3 of that log is?

 

3.14 X (0.75 X 0.75) X 4 = 7.065 m3

[Celtictimber]

Am I right in thinking that your getting the (0.75x0.75) as that is half of 1.5m. So I take it the calculation for a 2m wide log would be (1x1) am I on the right track?

[WeeDee]

Am I right in thinking that your getting the (0.75x0.75) as that is half of 1.5m. So I take it the calculation for a 2m wide log would be (1x1) am I on the right track?

 

That's right.

 

3.14 X (half the diameter times half the diameter) X length = volume

 

Keep all units the same eg. metres.