dimension lumber

[Magicman]

I really don't remember how many "whole houses" have been built with my WM lumber.  One was completed in December.  The carpenters commented about how true the lumber was.  They may flip it a couple of times trying to find the "crown" side.

It's accuracy was determined by my cheat sheet,  my turning cants when  signs of stress were observed, and the WM SimpleSetworks.  I never actually measured any board.

[ErikC]

 Thanks Jeff.

[Chuck White]

I agree with Jeff, and if I can keep it within 1/16" tolerance, that's close enough.

[dnalley]

Trying to hold rough sawn lumber to 1/64 inch in my opinion is just flat out amazingly STUPID! plus or minus within a 16th is perfectly tolerable for rough sawn lumber. Sure, its great to be right zeroed in, but falling in the center for average is all you ever need to do. I would have lost my job well before I reached 100 million board feet if it wasn't.

Talking about 1/64 tolerance here as a standard is simply an unfair thing to do for those coming here to seek out information, because it's really baloney to use as a blanket statement.  The only possible reason to hold rough sawn to that standard if it is going to be used for a specific FINISHED product demanding that tolerance. Then its no longer a rough sawn product, its a finished product.

Rough sawn is not a description of the board texture, its a description meaning, it is roughly the size of what it will be when finished.

To me this purty much sums up this whole debate about rough sawn lumber!  Having worked many years as a toolmaker, it would surprise me if most people could even feel the difference in .015" on a sawn board.  In any case if you cull those boards that don't measure within this tolerance, my guess is that your cull pile will far exceed your good pile.  Just trying to be realistic here :.

[ARKANSAWYER]

 







  I use hangers and connectors in pole barns all the time.  Some times in the frames like above we put the perlins between the rafters and they go on hangers.  Often there are wall inside and they just take off from the girts and we use hangers there to help hold them. 

  When sawing lumber if we are with in 1/8 of an inch all is well.  Most I would say falls in 1/16 to 1/8th.  But then we do less then 1mmbdft a year.  I have very few rejects and sometimes the cant just moves or things go wrong. (Yep it happens to the best sometimes.)  Most pole barns are not held to very tight specs and most new high dollar homes are not that square or plumb.  And if my Accuset 2 would round to the nearest 1/8th I would be happy.

[red oaks lumber]

thankyou jeff

[moonhill]

ARKANSAWYER, if you don't mind me asking, what holds the structure you pictured together from side to side?  A recient photo of a barn with the roof in a flatish state due to snow loads makes me ask the question. 

BTW, I was not yelling.   

Tim

[Dave Shepard]

I am not saying anyone has to hold their tolerances to anything other than what will work for them. I merely replied to the comment that sawing lumber to fit a joist hanger right off the mill is not doable. I attribute the accuracy of the lumber I saw to the setworks on the mill, and paying attention to the cant. For those who think I should not be sawing lumber as accurately as I do, what do I do to make it worse? Run a dull band? Never flip a cant? Push the feed speed until the engine almost stops? As I said, the worst lumber I could make would be to push really hard in knotty white pine, and even that saws well with a sharp band. I don't putt-putt along, but I don't hurt the machine, either.

[Jeff]

I don't think that's what anyone is saying at all. If you have a system to hold to such a consistency that's awesome.  I think a little bragging and boasting is even in order when you can do that. Heck, I could hold even closer then a 1/16 on the circle mill if I worked at it, probably closer to 1/32, but I know that was just me being anal and not at all nessesary for the application.

HOWEVER

My feelings are that we should never insinuate on the forum (and I'm not saying you are Dave, not at all)  that a tolerance like 1/64 is the norm or even logically achievable for the vast majority of sawmills and sawyers.  Why?  One big reason is because the Forestry Forum's information comes up so often in internet searches. Its not something we want to have new sawyers that come here to believe, and its certainly not something you want a potential customer to think, because they are both in for a disappointment. I can just envision some unsatisfiable sawing customer thinking that the saw job they just had done was not anywhere near as accurate as they thought it should be, and then start researching how accurate it could be, and end up here and find figures that support their unsatisfiable position.

[rpg52]

I've built three "pole" buildings, a barn and two sheds.  All three had metal connectors in them.  The barn had a second floor for hay storage - joist hangers nailed to beams bolted between the poles, and the floor joists topped with plywood.  The 2x10 rafters had metal straps connecting them over the peak before the roofing was applied.

The two sheds have either hurricane ties or metal strapping (it now comes in ~25' rolls) that I clipped off about 1' pieces.  They were nailed on top of the 2x6 rafters, then down to the beam to make sure a big wind didn't carry the roof away.  None of this was inspected by any authority - I've seen what a gust of wind can do to a roof, and it is cheap insurance if you ask me.
Ray

[beenthere]

Regards tolerances that are norm for the industry or norm for machine centers within high-production mills, there is money to be made by keeping the size tolerances to a bare minimum.

Sawmill studies in quality control are set up to continually monitor machine centers to determine when bearings are going bad, when sawblades are getting dull, or when something is failing to do the job. I think an earlier post referred to such monitoring within a mill.

The tighter the tolerance, the tighter the target size can be at each machine center breaking down the log into 'sticks'. All this means is more of the wood from the log going into the final product and not going out the planer blower into a chip van. Chips are not worth as much as solid lumber.

Some companies run some pretty tight ships, and wring every bit out of their wood possible.

So norm for the goose may not be norm for the gander...or somethin like that.  ;D

[Shotgun]

So norm for the goose may not be norm for the gander...or somethin like that.  ;D

I think I resemble that remark.                                                             :D

Norm

[backwoods sawyer]

Regards tolerances that are norm for the industry or norm for machine centers within high-production mills, there is money to be made by keeping the size tolerances to a bare minimum.

Sawmill studies in quality control are set up to continually monitor machine centers to determine when bearings are going bad, when sawblades are getting dull, or when something is failing to do the job. I think an earlier post referred to such monitoring within a mill.

The tighter the tolerance, the tighter the target size can be at each machine center breaking down the log into 'sticks'. All this means is more of the wood from the log going into the final product and not going out the planer blower into a chip van. Chips are not worth as much as solid lumber.

Some companies run some pretty tight ships, and wring every bit out of their wood possible.

So norm for the goose may not be norm for the gander...or somethin like that.  ;D

Well put, Beenthere.
Sometimes I am not as elegant of a writer as some, and my point is missed in the confusion of the debate that follows. When I was referring to the industry standard, I was referring to mills that have an annual out put of 400+ million bft a year. After all they are setting the standards for the industry.
I believe the point that I was trying to make here is that quality control is important no matter the size of your operation. Measuring a log that you just milled will not only tell you how accurate you are from cut to cut, but also alert you to other issues as well. If 1/16", or 1/8" or even 1/4" is your mills target for accuracy and you find that you are consistently out of speck then you should be alerted to the possibility that there may be an issue with your mill. Taking the time to make checks to know how accurate you mill is cutting to me should be as automatic as checking the oil, fueling the mill and lubing it. Not checking the mill for accuracy from time to time is like running with blinders on and hoping for the best.

[moonhill]

Trying to hold rough sawn lumber to 1/64 inch in my opinion is just flat out amazingly STUPID!

This is an interesting comment comming from an administrator.  Glad to see it addressed.

Tim

[Norm]

So norm for the goose may not be norm for the gander...or somethin like that.  ;D

Well it's one thing to be introspective with lumber but let's keep the name calling to a minimum. :D

[Magicman]

The dryness of the log is a huge consideration.  Lumber cut from a "bug killed" log will shrink less than a "fresh cut" log.   Shrinkage will determine the final dimension of the lumber.  I have found that generally oversizing 1/16" on bug kill, and 1/8" on fresh will result in "building quality" consistency.

Store bought lumber was sawed oversize, kiln dried, and then the planner mill determined it's final size.

[ARKANSAWYER]

  The barns get bottom cords, like 2x8 bands for the walls and ends of the buildings. 

  The industry standards may be a bit tight but for the most part they do not wring out much more lumber.  Case in point.  If I saw grade at 1 1/16 and keep my machine in top form and watch my blades I can always meet the standard of my wholesaler.  Now I only have to make 19 cuts in a log to make another board to make all that effort pay off.  Problem is 90% of the logs I saw will not make that 19 cut requirement.  The last time I bought studs at the store I could see the saw marks in the lumber and they were a bit below 1 1/2 and of poor quality.  These are things that keep me in business.  But some where is the fine line between production and quality of product and this is where you need to find and stay.  If you are looking to stay in the 1/64th range then you do in fact have very high standards but you may starve to death with them.  When all you do is saw and your income depends on your ability to produce good lumber in amounts that can pay all the bills then you may find your standard in the 1/8th range.  And this is why I own a plainer and a LOGOSOL PH260.

[Jeff]

When I was referring to the industry standard, I was referring to mills that have an annual out put of 400+ million bft a year. After all they are setting the standards for the industry.

But not the industry of the overwhelming majority of people that use the Forestry Forum.

I do believe you should always strive to be the best you can be and the best you can do, but only to the point that is does not becomes detrimental to the overall picture. We had a discussion one time where it was suggested you never, ever, never throw a grade board away if you can take it, because the BF value was so much more then the bf value of the center railroad tie as an example, even if it sacrifices the ability to get the tie. 

Tripping over dollars to pick up pennies is a good saying for that. Which leads me to a story...

The owner of the mill I worked for used to spend a lot of money going places and doing things. One spring he decided to fly out to Colorado where his daughter lived to visit and play some golf. Mostly to play Golf. He was a golf nut and part of the mill property contained a driving range that I help build. Anyhow, just after landing at the airport, he was walking through the terminal and saw a penny laying on the floor. Well, he could never leave a penny lie. So he rushed over to it, and just as he was bent over and was reaching to pick it up, he somehow got tangled in his carry on strap, lost his balance and fell forward with his hand and fingers extended.  He ended up in the emergency room there with two broken fingers. Of course he never got to play golf.

We got our selves into trouble upon his arrival home.  We had learned what happened, so we shut the water off to his office toilet, flushed it and let it drain and dry, then super glued a penny to the bottom of the bowl.  He didnt find that any funnier then he did when we had filled the same toilet to the top the previous year with range balls.

[backwoods sawyer]

The dryness of the log is a huge consideration. 

I know that big production mills and small portable mills do things different. For example, most of the small mills do not carry a large inventory of logs, therefore we mill some green and some dry depending on what is available. The large mills in this area still high deck there logs and sprinkle them, this helps them to have consistent runs where the dryness of the logs will be close to equal for a week or two, depending on the deck. You can always tell when they break into a new deck because the dryness if the logs will fluctuate briefly during the change over. Not only dose this give them consistency in sawing but also in drying. When you have 48 units per track and you load a double track kiln, this becomes even more evident. 56 hours in the kiln makes a big difference in the bottom line compared to 72 hrs for a green load. Running short kiln times can give you significant kiln degrade by cooking the top layers of the wood.
If we take a close look at the big production mills and keep an open mind, we can come away with changes that can benefit each of our operations whether you are running a 1940's mill or a 2010 mill. Jeff you have worked a bigger mill, I do not know the vintage of the mill that you worked for, or the product produced, but you have seen first hand how production mills are both similar and different from the small portable mills.