Thread: calculating the volume of logs.

Originally Posted by weisyboy

just wondering how others calculate there log volumes.

i use
"diameter squared x .07854 x length"

i just find it easiest on my phone calculator.

You could try this (desktop) browser based calculator Lineal Metres to Cubic Meters Calculator Converter

or the mobile version, if your phone handles the web ok (ie:iPhone) Lineal Cubic Volume Cost | Metric Imperial

:

i use the same but at the middle of the log you can use the same equasion but i use .7853xD1xD2xlength (D1 being the big end and D2 being the small end) giving an overall diameter of the whole log.

3.14 x radius x radius x length. If I am working out log weight I average small diameter and large but if I'm trying to work out how much timber I will get out of the log I work on smallest diameter.

Originally Posted by weisyboy

just wondering how others calculate there log volumes.

i use
"diameter squared x .07854 x length"

i just find it easiest on my phone calculator.

I hope you ain't charging people on log volume using that formula, your decimal point is in the wrong spot

I use the same as Mark (pi times the radius squared times length)

Spot on Burnsy and West OZ Mark and once you have your cubic meters times this by 1.2 to get an approximate weight for green WA hardwoods for those who need to lift them.

I use PIxRadius squaredxdiameter. I get the average of the radius each end and average the two ends to give the radius used in the formula.
Weight-wise, I carry a spreadsheet of timber densities/properties with me, so I use species related values to calculate mass.

yer thats what i said

0.7854

using both ends is a good idea.

Calculator for most applications here:

Builders Construction Calculators - Contractors, Tradies and DIY

When I'm loading logs on the truck everything is calculated as being 1-1.2 T per cube for safety (to go with S.W.L. of crane) when the truck is loaded I do a volume of the space it takes up on the tray and multiply that by .8-1 T per cube so I am always under my load limit

online calculators are good but a bit hard when ya in teh middle of teh scrub at the end of a long day.

Originally Posted by Sigidi

I use PIxRadius squaredxdiameter. I get the average of the radius each end and average the two ends to give the radius used in the formula.
Weight-wise, I carry a spreadsheet of timber densities/properties with me, so I use species related values to calculate mass.

Do you mean PIxRadius squaredxlength, if not you must have funny fat little logs

Originally Posted by Krunchie

When I'm loading logs on the truck everything is calculated as being 1-1.2 T per cube for safety (to go with S.W.L. of crane)

Heh. As far as I'm concerned, the SWL of the crane is exceeded when it won't lift whatever it's attached to...

And the truck's overloaded when it won't take off in second on the flat...


LOL, not quite, but it's not rocket science, is it? Having loaded and carried probably 100 loads with this truck, I'm pretty well able to gauge a load by eye and I reckon most experienced operators would be the same.

As for log volume, well they're just cylinders. Anyone here should have learnt the formula for cylinder volume in grade 7 or 8. What I find most tricky is assessing the yield from logs that are slightly imperfect ctlinders. For example, if a log is slightly out of round in one section, how far do I reckon the sapwood will intrude into otherwise useful cutting lines? Do i try for a few shorter boards in case, or do I just bash it through and resaw into whatever I can get?

We cut about a cube of product a day on average, but the total log volume required to feed the mill can vary a great deal, which changes costs quite a lot. I wish I could get someone to work on a piece rate, the way funky chicken does.

Forestry has for sale log volume calulator books.
Using a log tape, the log length and centre diameter measurement are read using the tape, and these are cross referenced to provide the volume. They also provide calculations for pipe volumes.
Regards
Greg

Originally Posted by Burnsy

Do you mean PIxRadius squaredxlength, if not you must have funny fat little logs

Good pick up Mike - I must have been sniffing sawdust that day