% Wastage from milling Sawlogs

[arboriculturist]

The hoppus measure is a long way out on dimensioned softwood though. Instead of 20% wastage, it's more like 40%

 

Wow Jon! - Well you should know.

 

I vote you produce and publish 'The Big J foot guide' - who knows it may be more lucrative and easier on the body than milling!

 

Have you a view on Hardwoods? 40% wastage also?

[youcallthatbig]

when I am cutting H/W boards, c/w 2 SE the following recovery rates are as follows per species:

Ash 75-80%

Oak 60-70%,

Syc 75-80%

 

but this is cutting 1st and 2nd length timber only, beam will less, unless you cut boards on the way to arriving at your beam section, recovery might be 40% or less depending upon your choice of raw material.

[growforest]

Why try to figure it out? You won't get a scientific answer. There are too many variables, too many "depends if"s. Just change your way of thinking toward co-product and you could be selling all of it and recovering 100% if you want to. And if you have time or resources. Or charge more for what you do sell and accept the "waste".

I mill mainly for myself for timber buildings now, in softwood, and am learning to glean every last stick out of every log. Many years ago when I started work in a hardwood sawmill, we just ran oak through for gateposts and logged the slab wood. Two fairly simple operations for every eight foot length, and very profitable. The dust went to the abbatoir and now and then bark went somewhere for tanning. Rotten bark became potting compost for the tree nursery. Zero waste.

[wills-mill]

Mr Edmund Hoppus published the initial Hoppus tables. The method of published tables had been used previously, but I believe he was first to use an imperial decimal system (ie 48.75hft rather than 48 3/4 as printed). There's mention of an alternative system used by the Admiralty (which may have been more realistic), where you don't divide by 144, but (memory not serving well) possibly 128?

EDIT: no, scratch that, the Admiralty measure gives a larger figure for a given log size....

 

Hoppus ft is an entirely theoretical volume, found within perfectly cylindrical logs and the system doesn't take account for saw cuts or processing as far as I'm concerned. For true content it is probably best to measure quarter girth at the small end of the log, not midpoint.

For actual milling scales, in the States they seem to use 3 (more? anyone?). From memory and the old Wood Mizer paperwork there's Doyle, Scribner, and Decimal C. They made allowances for circular saw cutting, so any band mill should be able to cut overscale.

 

Anyhoo that's all by the by. If you can recover 60 to 70% of your initial log, you are doing well. There will then be further loss to consider- your customer may be paying for a smaller proportion, as you may well take a 14ft log to create a 12ft beam, and maybe only get a couple of gravel boards out of the slabs.

 

All the way down the line there will be minor losses due to internal defects, crosscutting, drying defects, planing..... Daily output of the saw is not the same as output of the yard

 

The quality and usable volume that you get from the log is much more down to the operator than the price of the saw

Edited November 21, 2015 by wills-mill

[arboriculturist]

Mr Edmund Hoppus published the initial Hoppus tables. The method of published tables had been used previously, but I believe he was first to use an imperial decimal system (ie 48.75hft rather than 48 3/4 as printed). There's mention of an alternative system used by the Admiralty (which may have been more realistic), where you don't divide by 144, but (memory not serving well) possibly 128?

EDIT: no, scratch that, the Admiralty measure gives a larger figure for a given log size....

 

Hoppus ft is an entirely theoretical volume, found within perfectly cylindrical logs and the system doesn't take account for saw cuts or processing as far as I'm concerned. For true content it is probably best to measure quarter girth at the small end of the log, not midpoint.

For actual milling scales, in the States they seem to use 3 (more? anyone?). From memory and the old Wood Mizer paperwork there's Doyle, Scribner, and Decimal C. They made allowances for circular saw cutting, so any band mill should be able to cut overscale.

 

Anyhoo that's all by the by. If you can recover 60 to 70% of your initial log, you are doing well. There will then be further loss to consider- your customer may be paying for a smaller proportion, as you may well take a 14ft log to create a 12ft beam, and maybe only get a couple of gravel boards out of the slabs.

 

All the way down the line there will be minor losses due to internal defects, crosscutting, drying defects, planing..... Daily output of the saw is not the same as output of the yard

 

The quality and usable volume that you get from the log is much more down to the operator than the price of the saw

 

There has been a great response to my post - so thanks for the efforts put in.

 

It is very apparent that when softwood saw logs arrive at £120 m3 + haulage retailing the sawn product at £250 - £300 a cube is a realistic figure.

 

I would endeavour as you mention, to use every part of the log, anything else would be poor stock management:thumbup1:

[wills-mill]

There has been a great response to my post - so thanks for the efforts put in.

 

It is very apparent that when softwood saw logs arrive at £120 m3 + haulage retailing the sawn product at £250 - £300 a cube is a realistic figure.

 

I would endeavour as you mention, to use every part of the log, anything else would be poor stock management:thumbup1:

 

No prob. It's tricky using the small bits, there's a real balance between saving money and blowing any profit by faffing about for ages to recover the odd kilo of timber. You soon start getting ruthless when you work out the economics of it.....

 

As with all these things, sometimes a tiddly order or product will lead to other things and great regular customers. Sometimes not

 

I do keep the tidier slabs for people to make up rustic sheddage (some went into a ranch steak restaurant recently), and if I'm buzzing into Chestnut for heavy fencing, I keep back 1 1/2in boards to knock into tree stakes.

[wills-mill]

It's also tricky to get good recovery if you've got one order for decent sized posts and nothing else on the books. There's only so many multiples of 5x5 or 6x6 in a tree.

Sometimes an order for boarding or smaller stud type material is a real benefit when milling larger sections, then you can get a steady build up of both as you work. The other thing to do is be knocking out a stock size with a few uses that can also be recut or planed in future.....

[arboriculturist]

No prob. It's tricky using the small bits, there's a real balance between saving money and blowing any profit by faffing about for ages to recover the odd kilo of timber. You soon start getting ruthless when you work out the economics of it.....

 

As with all these things, sometimes a tiddly order or product will lead to other things and great regular customers. Sometimes not

 

I do keep the tidier slabs for people to make up rustic sheddage (some went into a ranch steak restaurant recently), and if I'm buzzing into Chestnut for heavy fencing, I keep back 1 1/2in boards to knock into tree stakes.

 

That's looks like a tidy business you're operating there:001_smile: A decent floor surface is everything.

 

I agree about the economics of trying to glean every last inch and experience usually tell you when to stop.

 

One reason I published this post ' Re: % wastage from ...... is as I am considering buying a Mill I wish to fully research the economics before committing.

 

 

Thanks for posting.

[OliB]

I went thru a similar thought process, figuring out if I could make a profitable business out of sawing logs.

 

I started in early 2013 with is Logosol M8 chainsaw mill for regular use up to 500kg, with an alaskan mill for occasional heavier/loger logs.

 

I was keen to prove whether upgrading to a hydraulic mobile bandsawmill would be a risk.

 

I kept a record of top dia and length of each log (hardly a noticeable expense of time considering the slowness of manual log handling and chainsaw milling), and the amount and quality of timber produced. I worked out what this cost, and what the end product was worth, and factored in other costs to see what the profit really was.

 

I did 100 tonne of oak this way between early 2014 and mid 2015. In May I ordered a hydraulic, mobile woodmizer Lt40, which arrived at the start of september. I haven't looked back since!

 

Milling oak beams and sleepers i often get no more than about 50% to 60% out of each log into the beams specified by the order. To be safe I always count on wasting 50% when doing beams and bigger timbers. BUT, the other 50% isn't waste. I mill the rest to 1",2", 3" and sometimes even 4" slabs, which I re saw on the mill into other products. The trick is finding a market for them, but if you can it's the difference between getting by and doing a little better.

 

Then you get some logs that are no good for anything, but look ok. I had one day when the timber I milled cost more than the value of the beams produced because of various defects.

 

Making feather edge boarding "wastes" 70% of log. Again, if you have other things you can use the "waste" for, then you doing well.

 

The biggest caution I would say is finding a market at all. For main products or waste. That's one of the many reasons I started on a CSM before making a hefty financial commitment. There's no reason why you shouldn't start with a £30k machine. Just consider what market exists and what price you will need to charge per cubic meter (or whatever measurement you prefer) to get your piece of it.

 

Oli

[OliB]

It's also tricky to get good recovery if you've got one order for decent sized posts and nothing else on the books. There's only so many multiples of 5x5 or 6x6 in a tree.

Sometimes an order for boarding or smaller stud type material is a real benefit when milling larger sections, then you can get a steady build up of both as you work. The other thing to do is be knocking out a stock size with a few uses that can also be recut or planed in future.....

 

If you don't mind me asking, what do you use to point your fence posts?

 

Oli