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Doyle scale over run

Started by Fern Wood, January 25, 2020, 02:37:17 PM

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Fern Wood

Since I am new to milling I have been checking my footage from log to lumber. Sawed a 19" straight log with little taper and ended up with 27% over run. I was surprised it would be that much unless I made a mistake . Does that amount of over run sound right with the Doyle scale? Sawed with bandmill.

donbj

The Doyle scale has slabs and 5/16 saw kerf built in to it. that's where you gain with the bandmill
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Fern Wood

Converted the Doyle footage to international 1/4 scale and my lumber footage would have been 3 board feet under log footage. Tried to google an international 1/8 scale but couldn't find anything 

clearcut

The Rule of Thumb formula for 1/8" kerf International Board Foot Volume is:

     Board Feet = (0.66*D^2  - 2.12*D) *(Length/12)

    where D = diameter inches at same end, length is in feet.

The longer version of this formula, and source for this is "A Collection of Log Rules", F Freese:

     https://www.fpl.fs.fed.us/documnts/fplgtr/fplgtr01.pdf

Carbon sequestered upon request.

donbj

I'm a licensed log scaler in BC since the mid 90's. We use the metric scale here and measure and account for all firmwood in the log, including taper. It seems like a fairer system to me than doyle. Then it's up to the sawyer to utilize it how he wants.
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Fern Wood

I would think if your using international you better have some strict deductions for sweep and what not whereas Doyle is built in . For a beginner anyhow.

donbj

Quote from: Fern Wood on January 25, 2020, 04:10:43 PM
I would think if your using international you better have some strict deductions for sweep and what not whereas Doyle is built in . For a beginner anyhow.
With the BC Metric scale the log is still scaled for complete volume. We also grade the logs as well. That's where sweep,crook, knot size, checks and other things are assessed.
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Nebraska

Buy based on Doyle.  :) Add back a little for the narrow kerf to make it fair.

longtime lurker

Quote from: donbj on January 25, 2020, 04:40:12 PM

With the BC Metric scale the log is still scaled for complete volume. We also grade the logs as well. That's where sweep,crook, knot size, checks and other things are assessed.
The way we do it here we have established limits for acceptable defect - knot size, bend deflection, pipe, slope of grain etc. If it's under the limit its a log.... if not it can be taken as optional (at a reduced rate) or docked out or left in the bush. But it's sold by the cubic meter or tonne as a log based on complete volume of what you take - either compulsory or optional - and the sawyer has to deal with it regardless.
All ways work - it's just that sales on complete volume price the log cheaper per unit because the waste is paid for too rather than deducted. HA!!! to the idea of over run on a sale in cubes or tonnes - hardwood mills in this state work on being viable at 30% recovery.
The quickest way to make a million dollars with a sawmill is to start with two million.

Southside

Doyle is not really a fair way to scale smaller logs. 30" and more and your going to be a lot closer to International 1/4" volume. 
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Larry

I input log diameter and sawn yield using Doyle for several months in excel.  I found yield could exceed 50% in small 10-12" logs.  The yield would decrease as logs got bigger.  Around 30" Doyle would be close to actual yield.

I've read Doyle was invented to penalize loggers for bringing small logs to the mill.



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donbj

Quote from: longtime lurker on January 25, 2020, 06:06:09 PM
Quote from: donbj on January 25, 2020, 04:40:12 PM

With the BC Metric scale the log is still scaled for complete volume. We also grade the logs as well. That's where sweep,crook, knot size, checks and other things are assessed.
The way we do it here we have established limits for acceptable defect - knot size, bend deflection, pipe, slope of grain etc. If it's under the limit its a log.... if not it can be taken as optional (at a reduced rate) or docked out or left in the bush. But it's sold by the cubic meter or tonne as a log based on complete volume of what you take - either compulsory or optional - and the sawyer has to deal with it regardless.
All ways work - it's just that sales on complete volume price the log cheaper per unit because the waste is paid for too rather than deducted. HA!!! to the idea of over run on a sale in cubes or tonnes - hardwood mills in this state work on being viable at 30% recovery.
Sounds like a very similar system. Knot size and spacing limits, rot, collar around defects, spiral twist based on diameter etc, per grade. We have Grade 1 and 2 for sawlogs. Beyond grade 2 it goes to grade 4 where if the logger knows a bit about grades he can leave it in the slash pile with no penalty on waste assessment.
This is Interior Scaling (interior of the province) where my licence is valid. On the west coast it's a whole different ball game with a Coastal Scalers license. My hats off to those guys they have a list of grades much longer than interior scalers deal with and have to retain a ton of knowledge. They deal with the huge coastal wood that has far more uses and qualities than the smaller interior wood. Though we can get some real nice big wood still within the more remote drainages still.
I may be skinny but I'm a Husky guy

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longtime lurker

Quote from: donbj on January 25, 2020, 07:54:30 PM
Quote from: longtime lurker on January 25, 2020, 06:06:09 PM
Quote from: donbj on January 25, 2020, 04:40:12 PM

With the BC Metric scale the log is still scaled for complete volume. We also grade the logs as well. That's where sweep,crook, knot size, checks and other things are assessed.
The way we do it here we have established limits for acceptable defect - knot size, bend deflection, pipe, slope of grain etc. If it's under the limit its a log.... if not it can be taken as optional (at a reduced rate) or docked out or left in the bush. But it's sold by the cubic meter or tonne as a log based on complete volume of what you take - either compulsory or optional - and the sawyer has to deal with it regardless.
All ways work - it's just that sales on complete volume price the log cheaper per unit because the waste is paid for too rather than deducted. HA!!! to the idea of over run on a sale in cubes or tonnes - hardwood mills in this state work on being viable at 30% recovery.
Sounds like a very similar system. Knot size and spacing limits, rot, collar around defects, spiral twist based on diameter etc, per grade. We have Grade 1 and 2 for sawlogs. Beyond grade 2 it goes to grade 4 where if the logger knows a bit about grades he can leave it in the slash pile with no penalty on waste assessment.
This is Interior Scaling (interior of the province) where my licence is valid. On the west coast it's a whole different ball game with a Coastal Scalers license. My hats off to those guys they have a list of grades much longer than interior scalers deal with and have to retain a ton of knowledge. They deal with the huge coastal wood that has far more uses and qualities than the smaller interior wood. Though we can get some real nice big wood still within the more remote drainages still.
Here on a private sale grade is whatever is negotiated between buyer and seller. On a Crown (state) sale there are but two grades - compulsory and optional. And I guess a third at "that bad it's not a log". They changed to a two tier system with high defect allowances to increase utilisation of viable log... but in effect it's meant the acceptable defect level is pretty high (lower grade of log classed compulsory) so it pushed the price of logs down to compensate for the increased amount of trash going to the mills.

You can work the system a bit... leave a defective butt on a log and another head defect and it's an optional so you pay less per cube then clean it up for a compulsory log at the mill. But mostly its a gamble... I bid high on my last crown sale expecting high grade sawlogs and some veneer grade mixed in... and got stuck with one step above optional stuff that means I pretty much need to save up to saw them.

I've seen a chart and I'm pretty sure it came out of B.C. for converting cubic meters of log to MBF recovered. I can't remember the details or where I found it but I do remember that based on the logs coming out of my crown sale my magic number was 7: ie I had to saw 7 cubic meters of log (or 2961 BF of unscaled log) to get 1000 BF of wood. It was pretty much right on the money. If you ever run across that thing I'd surely like a copy/link/whatever... I found it interesting for talking with our 'merican friends.

Personally I think the great equaliser when trying to compare apples with oranges is tonnes or any other weight scale, as that factors in the density issue. My experience is that a ton of pine  and a ton of oak and a ton of ironbark all cost about the same to saw in terms of time, effort and wear on the gear. The ton of pine has more BF (or cubes)... but the cost of sawing per BF is less than the harder woods. On a weight basis it all evens out though.
The quickest way to make a million dollars with a sawmill is to start with two million.

donbj

Quote from: longtime lurker on January 25, 2020, 11:21:16 PMI've seen a chart and I'm pretty sure it came out of B.C. for converting cubic meters of log to MBF recovered. I can't remember the details or where I found it but I do remember that based on the logs coming out of my crown sale my magic number was 7: ie I had to saw 7 cubic meters of log (or 2961 BF of unscaled log) to get 1000 BF of wood. It was pretty much right on the money. If you ever run across that thing I'd surely like a copy/link/whatever... I found it interesting for talking with our 'merican friends. Personally I think the great equaliser when trying to compare apples with oranges is tonnes or any other weight scale, as that factors in the density issue. My experience is that a ton of pine  and a ton of oak and a ton of ironbark all cost about the same to saw in terms of time, effort and wear on the gear. The ton of pine has more BF (or cubes)... but the cost of sawing per BF is less than the harder woods. On a weight basis it all evens out though.
-----------------------------------  

I can't recall a chart like that, though I think your 7m3 of wood for a 1000bdft may need looking at. I don't understand the 7m3 for 1000bdft. I ran the truck scales at a local mill for many years and did the sample scaling which produced the conversion factors per stratum, m3 per tonne, the contractors and any private wood as well got paid by. I asked the production side of things a few times along the way what the production numbers were per cubic meter. They were usually between 250-270 bbdft/m3 which puts it at up to 4m3 per thousand bdft. Another local mill was around 260 bdft/m3

I have tracked the numbers with my LT40 as well on some jobs. In nice size wood where I tracked the scale, I have got up to 300 bdft per m3 at times.

The weight system can be quite fair if consistent measures are implemented when setting up the stratum plan. Variances and inconsistency can raise its head when wood from other geographic areas gets weighed into the same stratum as the local wood. I have seen spruce vary up to 15% especially when it's the bigger stuff. That can work for or against each side at times. Unless every load is hand scaled, that's how it works. There's discrepancies in all systems. If my memory is correct we had 13 or so stratums at the mill.
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longtime lurker

Quote from: donbj on January 26, 2020, 12:24:37 AM
Quote from: longtime lurker on January 25, 2020, 11:21:16 PMI've seen a chart and I'm pretty sure it came out of B.C. for converting cubic meters of log to MBF recovered. I can't remember the details or where I found it but I do remember that based on the logs coming out of my crown sale my magic number was 7: ie I had to saw 7 cubic meters of log (or 2961 BF of unscaled log) to get 1000 BF of wood. It was pretty much right on the money. If you ever run across that thing I'd surely like a copy/link/whatever... I found it interesting for talking with our 'merican friends. Personally I think the great equaliser when trying to compare apples with oranges is tonnes or any other weight scale, as that factors in the density issue. My experience is that a ton of pine  and a ton of oak and a ton of ironbark all cost about the same to saw in terms of time, effort and wear on the gear. The ton of pine has more BF (or cubes)... but the cost of sawing per BF is less than the harder woods. On a weight basis it all evens out though.
-----------------------------------  

I can't recall a chart like that, though I think your 7m3 of wood for a 1000bdft may need looking at. I don't understand the 7m3 for 1000bdft. I ran the truck scales at a local mill for many years and did the sample scaling which produced the conversion factors per stratum, m3 per tonne, the contractors and any private wood as well got paid by. I asked the production side of things a few times along the way what the production numbers were per cubic meter. They were usually between 250-270 bbdft/m3 which puts it at up to 4m3 per thousand bdft. Another local mill was around 260 bdft/m3

I have tracked the numbers with my LT40 as well on some jobs. In nice size wood where I tracked the scale, I have got up to 300 bdft per m3 at times.

The weight system can be quite fair if consistent measures are implemented when setting up the stratum plan. Variances and inconsistency can raise its head when wood from other geographic areas gets weighed into the same stratum as the local wood. I have seen spruce vary up to 15% especially when it's the bigger stuff. That can work for or against each side at times. Unless every load is hand scaled, that's how it works. There's discrepancies in all systems. If my memory is correct we had 13 or so stratums at the mill.
Nope my numbers are good - the number tossed around the industry here is 30% recovery being viable.... 10 cube of logs in to 3 cube of boards out.
For me being smaller it's more like 33% being breakeven and making money at 35. But also being smaller I do tend to get a higher recovery because the guy that drives the saws owns the sawmill and has a vested interest in maximising profitability. My crown sale is averaging about 28% recovery and is costing me money.... I'd hate to see what one of the big mills would get in those logs but I suspect maybe 20% tops. Unlike a lot of the big guys though I have sufficient volume of better quality logs to average that up, and it's just cheaper to do that than to break my supply contract with the state.

It's all priced in of course - the lower recovery rates are offset by lower log prices and higher wood prices. The joys of cutting the denser eucalypts.... spring in the little ones and pipe in the big ones..... but (subject to exchange rates) I can ship them anywhere in the world and have the strongest, most durable timber in a market and that has a value. About the only place where it doesn't rate a premium is locally because that strength and durability is considered "normal". The biggest problem we face here as an industry segment (hardwood framing) is pine. I can buy framing pine for between 1/3 to 1/2 the cost of producing boards. The pine is nowhere near as strong, and your house will fall over in 40 years rather than your grandkids living in it, and there wont be no dancing on your floors in stiletto heels... but its cheap, and most people can't see past the initial price to the whole of life costings. I'm not too worried about it - but in one way I'm glad my kids arent interested in the business.
The quickest way to make a million dollars with a sawmill is to start with two million.

stavebuyer

Your over run is what I would expect on that diameter. Doyle was designed to penalize small logs in an era when they were still cutting virgin hardwoods. It is what it is and prices are usually higher per foot to compensate. Its also the reason tie mills can be profitable on what appears to be slim margins.

moodnacreek

Quote from: stavebuyer on January 26, 2020, 02:48:40 AM
Your over run is what I would expect on that diameter. Doyle was designed to penalize small logs in an era when they were still cutting virgin hardwoods. It is what it is and prices are usually higher per foot to compensate. Its also the reason tie mills can be profitable on what appears to be slim margins.
                                                                                                        This is the answer to the doyle versus other scales. The traditional scale here is scribner but international is more used. When I started I would scale a log, int., saw it and measure the boards. To make the log scale with circle mill 1/4" kerf I had to skim and take the 1x3s that I leave in the slab today. People go on and on about log scales. I have found that log buyers will over scale a little to make themselves look good.  After all they set the price per thousand.

Ron Wenrich

When I marked timber, I would send footage totals in both Doyle and International, as well as breaking down totals in diameter classes.  Most buyers bought on the Doyle scale, as most log buyers buy on the Doyle scale, including the veneer buyers.  There was no call for Scribner in our area.  The state uses their own tables for sales, which makes it confusing in areas where state timber has an impact on log supply.

As for overrun, I could get about a 2% overrun of International sawing grade hardwoods on a circle mill.  But, we did saw blocking out of the hearts.  I didn't chase after short lumber or narrow lumber.  It was too much handing both from our side and on the other end.  We didn't have a select market, so my target on the opening face was 6".  My average loads sawing red oak sawlogs with the high grade logs taken out was over 50% F1F&btr.
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donbj

Quote from: longtime lurker on January 26, 2020, 02:15:35 AMNope my numbers are good - the number tossed around the industry here is 30% recovery being viable.... 10 cube of logs in to 3 cube of boards out. For me being smaller it's more like 33% being breakeven and making money at 35. But also being smaller I do tend to get a higher recovery because the guy that drives the saws owns the sawmill and has a vested interest in maximising profitability. My crown sale is averaging about 28% recovery and is costing me money.... I'd hate to see what one of the big mills would get in those logs but I suspect maybe 20% tops. Unlike a lot of the big guys though I have sufficient volume of better quality logs to average that up, and it's just cheaper to do that than to break my supply contract with the state.


____________________________________

That's interesting. Must be small wood
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longtime lurker

Quote from: donbj on January 26, 2020, 08:38:03 PM



____________________________________

That's interesting. Must be small wood
Yah, they're helping us transition to the plantation resource of the future. They haven't planted the trees yet up here but.... yanno they're the government it doesn't have to make sense.
The big one in my block is pipe. a 25cm diameter log can carry a 4 cm pipe and be compulsory. A 40 cm diameter can carry 19cm of pipe. A 50cm diameter can carry 28cm of pipe. A 60 can carry 34.... and by the time you get up to a 90 you can stuff a small child up the hole to look around with a flashlight. In these species the wood outside the pipe is perfectly fine.... pipe in no way affects the strength or durability of the surrounding wood. But it's pretty hard to get recovery when half the log is just a gaping hole.
The upside of learning to run a mill for profit cutting trash is that when I get good logs like my privately sourced ones I am just plain lethal... bad logs will surely teach you how to run a saw if you don't go broke first.
The quickest way to make a million dollars with a sawmill is to start with two million.

donbj

Quote from: longtime lurker on January 26, 2020, 10:09:05 PMYah, they're helping us transition to the plantation resource of the future. They haven't planted the trees yet up here but.... yanno they're the government it doesn't have to make sense. The big one in my block is pipe. a 25cm diameter log can carry a 4 cm pipe and be compulsory. A 40 cm diameter can carry 19cm of pipe. A 50cm diameter can carry 28cm of pipe. A 60 can carry 34.... and by the time you get up to a 90 you can stuff a small child up the hole to look around with a flashlight. In these species the wood outside the pipe is perfectly fine.... pipe in no way affects the strength or durability of the surrounding wood. But it's pretty hard to get recovery when half the log is just a gaping hole. The upside of learning to run a mill for profit cutting trash is that when I get good logs like my privately sourced ones I am just plain lethal... bad logs will surely teach you how to run a saw if you don't go broke first.


Ahh ok, I get you now, that certainly changes the game. Here the size of the rot/pipe in relation to the diameter can pretty quickly turn it to grade 4 especially on smaller wood. Lots(butt ends) gets trimmed off in the bush if rot is showing. The larger western red cedar can be bad for hollow and heart rot and if it grade 4's in the bush it can be left or sometimes a post and rail fellow would buy it.  
I may be skinny but I'm a Husky guy

Woodmizer LT40HDG24. John Deere 5300 4WD with Loader/Forks. Husky 262xp. Jonsered 2065, Husky 65, Husky 44, Husky 181XP, Husky 2100CD, Husky 185CD

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