Kerf loss

[nas]

I've been collecting Kerfs for years.  Have a whole barn full of them, but no market. They don't cost anything, I get them for the asking and they would be a good product to base a retail on, but, like I said, no market.

I've tried to push a few stretched points too.  All that ever got me was funny looks, so I keep them under wraps too.  Someday, mark my words, I'm going to be a rich man.  :P

My kerfs are always stuck in the log and as soon as I try to get them out they turn to dust ???

[KyTreeFarmer]

My kerfs are always stuck in the log and as soon as I try to get them out they turn to dust ???
[/quote]

Now thats funny, I don't care who you are!!
KTF

[PC-Urban-Sawyer]

... Someday, mark my words, I'm going to be a rich man.  :P

Tom,

I'd think that unmarked, perhaps even unused, words would be worth more than those that had been used and marked... :D

Herb

[ely]

not sure what the big blades have for a kerf. i have several of them but have never ran the blades thru logs.
i know at one time a couple years ago i could go over to the sawmill a circular rig, and purchase timbers of any diminsion for 25 cents a bdft. it costs me the same to buy logs from loggers.
i could not understand how they could afford to buy logs at that mill for 18 and 20 cents a bdft and sell product for 25-36 cents a bd ft.

i often thought about just buying a load of cants from them to saw on my mill. heck they already found all the metal in them for me. ;D

[coastlogger]

Around here, 52 inch and 54 inch circ blades all take 3/8 teeth. ive owned one and measured others.It must be one thin blade that takes a 1/4 inch tooth.Although I havent measured an MD lately(has anyone?) Im pretty sure the local MD mills take a 1/4 inch kerf.Guess you can get thinner blades for them too?
clgr

[Jeff]

 I was the head sawyer in commercial circle mills all of my working life prior to 2006, and never even saw a 3/8s kerf tooth let alone ran one. We ran almost exclusively 56" saws and the standard bits were 9/32s. One sharpening and they become less then a quarter inch.

[beenthere]

Couple of good articles in Sawmill & Woodlot mag this week, along the lines of this kerf discussion....Opening face, and grade sawing.  8)

[Jeff]

Your first cut, going into the log, kerf is irrelevant no matter what it is.

[Tom]

But, that last kerf.   Now, that's where it might get to be important. 

[Jeff]

That's right, its all relevant to the application and circumstance. That's what Arky, Ron and myself are trying to say. One answer is not always the answer. It always depends on the question.

[ely]

i see what the guys are saying on kerf loss though. circle mill will eat up more wood than a band mill. but i would like to have a circle mill just so i could say i have ran one before.

[Ron Wenrich]

When we first got our mill from Canada, they included a new saw with 3/8" teeth.  It had fewer teeth in it.  They said everyone in Canada used that type of blade.  I think it was one they had laying around.  I never sawed with it.

Of all the stacks that I built while sawing without a computer, I always used 1/4".  Even the computer uses 1/4".  Its always worked out right.

[Chuck White]

I know on my mill that when I use the yard-stick scale to saw with, I have to just split the difference on my last cut.
If I just put the pointer on the 1" mark, that last (bottom) board will be a little thicker.  As in 4/4 instead of 1".

[backwoods sawyer]

This Mighty Might that I have been running is using 3/8" kerk on both saws, add in the flex of the saw and a yard stick rule with jerky hydraulics and you have to allow 1/2" + or -. Now when compairing that to .110 kerf with accurate setworks and the dirence in these to machines is real clear, But as has been stated not all round saws are equel. On the other end of that equation is a thin kerf gang edger where the round saws are pulling .110 kerf. As a rule the more advanced the tecnology used in the design of the sawmill it's self, not the whole operation, the more eficiant it will be, less kerf equels less energy needed and results in higher qualty of cuts, or higher recovery rates, but idealy both. The more you pay for your logs and the more volume that you process the more relevant it all becomes.

[Meadows Miller]

Gday

On Circular Headrigs 
A 3/8th 9.1mm kerf would be on a 4 to 5  gauge saw plate and thats Heavy gauge to be using and generaly reserved for realy big saws and buck saws that need a stout body or cop abit of abuse  ;) Or idiots who dont know how to make a saw to run properly on their Mill  ;)  :D :D so they over compensate buy using a heavy saw  ;)  most mills run 7/8 gauge saw plates with 9/32 or 6.8mm kerf on the teeth on a 44" to 56" saw works well for anyone who knows what they are doing with a mill and you could go down to a slightly narrower kerf in harwoods but why bother  ;)

Regards Chris

[NWwoodsman]

(As a rule the more advanced the tecnology used in the design of the sawmill it's self, not the whole operation, the more eficiant it will be)
I'll take my 1960's technology any day of the week, things where built to last, and if they did brake you or a repair man could fix them. Know days if it brakes you throw it away and buy a new one, No more TV repairmen. Keep it simple, keep it running.

(less kerf equels less energy needed and results in higher qualty of cuts, or higher recovery rates, but idealy both.)
Yeah I'd disagree here too, Thicker blades cut more accurate and faster giving you a better product quicker. Costing you less per bft. I'll make more sawdust at the end of the but I'll also make more lumber, even without all the bells, whisltes and bright accuset lights. Used to be craftsmen learn how to do things on a manual machine, then you got to use a computer controled machine. So you understood the principles of machining.
Jason

[jim king]

As wood here in the Amazon is getting rather pricey I ask the question about kerf.  Here is what I found after a few days study.

Our 8 inch band mill looses over 50% of the lumber out of a log.

Our old  22" disc mill looses a consistant 50% of the lumber out of chainsaw cut cants.  The discount when scaling is 1" .  Meaning that if they bring in a 6" x 8"  cant we pay for 5" x 7 ".

Our little Baker resaw gains about 5% over what is scaled when we buy.  For the Baker we buy the wood in cants 7 feet long and when scaling reduce the size 1/2 inch.  The only problem is that we can only get about 1000 bf a day of 1".  But with the value of rough cut green 1" flooring lumber now at $1.60 and our wood costs US $0.40 delivered in cants to the mill, the little Baker makes more money than the big band mills or the disc mill.  For the cants used in the Baker we only discount 1/2" to the seller.

[sigidi]

Jim I'm surprised at the recovery rate from a bandmill, from the point of view the band mill is always hammered as a big winner in kerf over a sawblade, but the figures you are giving are way below the figure I run on my Lucas.

Recently had a little competition here in Aus and achieved almost 70% recovery in a race situation over two days of competition, I always work on recovering more than traditional hardwood mills, but was very pleased I got such a nice amount. Very interesting a band mill runs at a lower recovery when kerf thickness is harped on so much...

[paul case]

i dont understand whatt your saying jim.
who is scaling your logs? what scale? is that recovery of grade or what?
   the doyle scale  and my band mill always work out to where i get 110% or more than scale of boards or cants. guess i need a little more  info on what you are calling recovery.  pc

[jim king]

Here are a few more details about how we work here.  Most of the marketable woods in the 30 inch dia range have about 4 inches of white sapwood and up to 12 inches of bad heart.
Sawing on the big head rig is difficult to get an efficient yield in addition to the kerf being a problem.   Our buyers only buy FAS , no sapwood.  We scale Doyle coming in for tax reporting and the chain of custody.  When the product is finished we scale by the cubic meter for invoicing.
The loss between the waste wood for the kiln and the export wood for export is discounted as a loss on the income tax.
Our headrigs  without question have a ¼ inch plus kery and the 22" disc mill looses a consistant 50% form rectangular chainsaw cut cants.  The small resaw gaining with only a ½ inch discount I cannot explain yet.
For working in the tropics the most profitable way is chainsaw cants brought in and resawn.  Our longest product for flooring for the Chinese market is 6 ½ feet long down to 2 feet long.

[Ron Wenrich]

Is that last shot your operation?  I was under the impression that all the wood brought in was by chainsaw cant.  But, I see some mighty hefty logs and a big band headrig. 

I can see where a band resaw is better than your other headrig.  I wonder if it wouldn't make sense to square up one side on the disc saw before sending it to the resaw.  That would give you one square side.

[ARKANSAWYER]

 Well part of the problem is you are not compairing walnut to white oak.  You are using two different measures for two different yelds.
  The chain saw cants you are getting from the forest are already free of sap and heart wood.  You are just buying wood that you can sell.  The loss is saw kerf and drying shrinkage along with final machining of product.  A frame saw or a narrow kerf gangsaw would split them up most quick.  The Baker resaw is a better deal as it is a bit narrower kerf.  But with it you are losing money by production loss.  Your cant size might be a problem as well.  If you are buying 6x8x7' cants are you producing 6 inch wide flooring?  If not what is the final product size?
Case in point.  I have a guy who builds cedar furniture.  For years he bought 1x6x8' boards to build the stuff he made and he would come in and buy a $100 dollar bills worth each time.  One day he was griping about all the waste he had.  Seems he rips the boards to 2 1/2" wide and planes down to 3/4 and the shortest board he uses is 18".  Seems he has alot of 3/4x3/4 strips and alot of 14" long boards that he could do nothing with.  So I looked at his pattern and started making the boards 5 1/4" wide and 9' 4" long.  This was great! as he had less waste but he was mad because he was getting less boards for the same $100.00.  Even though he could build just as much furniture or more for the money he was getting less boards.  So now he is back to buying 1x6x8' boards and griping about the waste.
  In the logs you are processing you are not losing the wood due to kerf.  In a 30" 8 ft log you have 338 bdft but are throwing out  50 bdft of sapwood and about 60 bdft of heart wood.  So that means you discount over 30% away before you ever saw into the log.  The chainsaw cants have already left that in the forest.  The 8" head saw should just be making cants any way and feeding a gangrip.  So if a 30 inch log comes in you should only be paying 228 bdft for it or pay less money per bdft and buy at 338 bdft.  You should be able to process 50 mbdft a day with any kind of a good set up.
  Can you steam the wood to make the sapwood look like the heart wood like we do cherry and walnut?   

[jim king]

Yes those photos are of our operation here.  We are switching to 100 % cants asap  and buying more thin kerf machines , as we have no waste and a fixed cost for raw material with cants the profit margin is fixed and we are happy at the end of the day.   
With the forestry laws pushed on these small countries it is almost impossible to produce legal wood in any other form.
Plus using a skidder in the biggest swamp in the world is not any ones idea of a good day.

I want to get to 40 cubic meters a day  (one container) of finished product and I will be quite happy.

[Ron Wenrich]

Would your recovery rates be any higher if the cants were made more accurate?  That shouldn't be hard to do, and it isn't high tech or costly.

[jim king]

Ron:

I have no loss on the chainsaw cants.  These guys can cut very well.  My problem is the big rigs which I hope to get rid of asap.