Do you center the pith when you cut? Be honest :)

[OffGrid973]

Interested to see who takes the time to make the best lumber possible, as this is not a fun process on the manual mills. I was reading Marty's thread on quarter sawing and got inspired to ask.

[John S]

Yes, unless the customer tells me that he/she does not care.  That is after explaining it to them.

[Magicman]

"Always center the pith" to me is a much misused or misunderstood term.  So much depends upon where the pith is and which face that you intend to open.  I have seen logs with the pith on one edge on one log end and on the opposite edge on the opposite end.  Now whatcha gonna center?

Now back to sawing.  Probably 90%+ of my sawing is SYP for framing lumber which is much different from sawing hardwood for grade lumber.  Take this log as an example:


 
It is a very good and a very average SYP log that will become framing lumber.  You can't tell by the picture but the hump is on the left side and will be the last face that I open.  Also notice that the pith is centered top to bottom.  Had I rotated the log 90°and centered the pit, what would have become of the off center portion of the log that then would have been on the bottom?

Yes, in this instance I centered the pith to produce my targeted cut list and following this sequence I always do so, but the pith was not centered for the second and last face opening.

[Jeff]

If you are sawing grade lumber in hardwoods, you are throwing away money if you are centering the pith.

[Chuck White]

No!   We don't get very many "PERFECT" logs where the pith is in the center of the log!

To center the pith in these logs would create a large slab pile!  ;)

[rjwoelk]

I start off by getting it centred to a degree but usually its off to a side by the time i am done. But that is for cants. I find it wonders alot in Birch. and Hemlock is usually off to one side like MMs pine.

[DPatton]

As just about everyone has said it depends on the log and what your trying to get out of it. For most of the sawing I been doing lately (flat sawn boards) I don't worry about getting perfectly centered but rather focus on getting what I need out of the log. Now if I was sawing beams or producing quarter sawn material then centering the pith becomes more important and I center the pith according.

[longtime lurker]

EXACTLY what our fearless leader said. The only time I cut pith centered is when I want boxed heart beams. Other than that shes all 4 way taper, be it backsawn or quarter cut makes no difference.

[PAmizerman]

A vast majority of what I saw is 1" hemlock boards. I don't worry about centering the pith. The only time I "center
The pith is on slabs and beams. Well maybe I do. I center the pith on the face I can see. So if I want 1x10's I'll go up 5 inches from the pith to get my target width but I don't worry about where the pith is on the opposite end of the log or where it lands as I pattern down.

Centering is kinda a loose term it is actually just getting it the same equadiatstance from the blade. Most of us that have been around sawing for a while understand that but just wanted to clarify for any new guys. 

So which button do I check? :D

[JB Griffin]

Myself and all other real sawyers in my area take half the taper out of the log. Don't care where the heart is. 

I will add that we are tie mills that saw grade too.

[DPatton]

cwimer973,

To be honest I didn't vote in the poll because of how it is currently worded. In my mind I don't feel the question is valid as it lacks clarification of what type of product is being sawn. I suggest you modify the question to ask who centers the pith while sawing a certain type of cut, such as live edge slabs or timber frame beams or board and batten siding or quarter sawn boards, etc. etc. etc....hope this make sense.

[Magicman]

(I had to leave at 6:00 in order to get my 14 mile bicycle ride in before night/dark.)

Now as has been eluded to, your target cut list will determine how the log is set up for the initial face opening.  My picture above, illustrates that the pith will almost always be centered and my goal is to have that pith centered in my (center) cant for saw through.  If it is off from end to end, then I have to make a decision based on experience.

The "rules" for sawing framing lumber is much different than for sawing hardwood grade lumber.  Bow is generally acceptable with framing lumber because structural lumber can be "straightened" whereas using a crooked board may present a challenge. 

No one wants bowed grade lumber and crook can be edged straight.

Your initial face opening will determine whether your lumber will bow, crook, or twist.  I do not see sawing as a "one size fits all".

[PAmizerman]

cwimer973,

To be honest I didn't vote in the poll because of how it is currently worded. In my mind I don't feel the question is valid as it lacks clarification of what type of product is being sawn. I suggest you modify the question to ask who centers the pith while sawing a certain type of cut, such as live edge slabs or timber frame beams or board and batten siding or quarter sawn boards, etc. etc. etc....hope this make sense.

I did not vote either because my answer is yes, no, sometimes and it depends.

[Ljohnsaw]

I voted yes because I'm sawing softwoods (pine & cedar) making beams and posts.  I do generate a LOT of side lumber as well.  If I get down to just sawing 1x I can see just flat sawing (I think that's what its called), parallel to the bark to get the most/longest boards.

[Percy]

What is this "pith" you speak of??  :D :D

[Brad_bb]

Always.  I cut beams mostly so I want to symmetrically box the heart.  Sometimes the log is not straight, is wonky, or the pith wanders.  In that case do the best you can, and sometimes to get the size you want out of it, you may have to allow it to be offset a little on one end.  I try to leave at least 1/2 inch so if it moves in the first couple months, I can plane it straight.

[PA_Walnut]

Kinda depends what it is and what I am cutting. Mostly yes, however.

[SawyerTed]

Yes I "try" to center the pith.  Do I always get it right - no.  Do the logs cooperate - sometimes.  Often, in the logs I saw, the pith is centered on one end and off center on the other.  It is much easier to center the pith in the hardwoods I get than in the softwoods.

[Magicman]

You must know and remember where the pith is/was in the squared cant before sawing through.  That is why I say; establish your target before opening a face.

If the above pictured log is sawed through from the 3 or 9 o'clock faces the lumber will tend to bow which would be OK for general purpose and framing lumber. 

If from the 12 or 6 o'clock faces the lumber will tend to crook which should edge out after drying. 

If it is sawed through from either of the other 4 quarters it will tend to twist so you are on your own.

[mike_belben]

Click the quote to see the log MM is referencing.  

Can you tell all that just from the end grain?  

[Magicman]

 

 

Sure, all of the log is the same age but notice that the growth rings are wider spaced on the left side of the pith and narrowly spaced on the right side.  Because a board sawed through from 12 or 6 o'clock will contain a portion of these uneven growth rings the board will crook.

Now looking at the growth rings on the 6 & 12 o'clock sides of the pith we see that they are very evenly spaced.  Boards sawed from the 3 or 9 o'clock faces will have even growth rings and will not tend to crook but because these boards have passed the plane of the pith twice, they will tend to bow.

[mike_belben]

Welp, that was a pretty potent lesson.  Thank you sir. 

[Brad_bb]

MM, I assume by crook you mean crown?

[Magicman]

I suppose that you could call it that.  I prefer to use terms and definitions that are established  and yes, a crooked board would have a crown but I would not call it a crown board.

Wikipedia:  Wood warping - Wikipedia

[OffGrid973]

Thank you team for the responses, ok figured it wasn't an easy Answer.

For those who couldn't answer (like being difficult  ) I put you down as yes since you already thought about it to much to select NO.

So far I have learned that it's important and next time I have a crook I can investigate growth rings on both sides.  Of course Brad I would PM you a pic of my crown

Good topic, if any other pith'y topics are sparked please include them.

[DPatton]

Thank you team for the responses, ok figured it wasn't an easy Answer.

For those who couldn't answer (like being difficult ) I put you down as yes since you already thought about it to much to select NO.

:D :D :D Guilty as charged, wife says I'm difficult too.

[Bandmill Bandit]

I generally center the pith by eye balling it,  BUT when accuracy is a must, I take the time to do it by measuring.

[Ianab]

I generally center the pith by eye balling it 

Same here. With the Swingblade your sawing is slightly different, but I generally adjust the bunks to approximately level the pith, and keep some 1 and 2" offcuts around just for purpose. 
But sometimes you might not want that.  A log with a "Good" side, and an "Ugly" side, you might be better to saw it parallel to the bark on the good side, and if the rest is all knots and bug holes, it gets chucked in the firewood pile. 
So it's better to say that you adjust the level of the log for best results. Usually that's "level", but taper sawing to follow the bark, not the pith, is also a "thing". It means more of your waste wood is left in a wedge shaped piece around the pith, and not in fat short slabs. The outer wood can be clear, straight grain and valuable, while the pith area might be knotty / cracked / rotten.  Better to throw that pith wood on the firewood pile, and keep a couple of better outside boards instead.

[Brad_bb]

MM, in stick construction I have always heard it referred to as crown.  As in crown out etc.

[Magicman]

Sure Brad, when hanging rafters I always put the crown of a crooked rafter up.  Same with crooked joists turning the crown up, but that does not change their definition to a crown rafter or a crown joist.  They are both crooked which gives them a crown.

[Brad_bb]

Well then I just want you to know " I am not a crook"

[Magicman]

I was just looking for your crown.  

[rjwoelk]

MM your humours logic is killing me. :D

[moodnacreek]

Take a nice, clear 1x12 say 12' long and make 2 1x6 from it. Often you will get 2 rockers because the 'heart was not centered even thou the heart is not in that board.  It is the same as sawing to close to the heart on 1 side of the log while making boards and then the cant springs. This is always true in hardwood and often softwood.

[Sixacresand]

I center the pith as near as possible and keep pith in the center of middle boards or beams.  Success depends on log quality.

[longtime lurker]

Okay so Im trying to clarify something here.

I might have killed a few logs for framing in my time but pine is a four letter word to me, and what i mostly cut is inclined to make boomerangs at the best of times anyways so maybe im losing something in translation or its because of the huge differences in the species we saw.

To me centering the pith has little to do with bow in a board. I look at Lynn's picture and yup... I agree with his analysis of how I would expect that log to move so far as spring (crook) is concerned, and I'd align it in the same way so far as the relationship of log to deck. But then Im going to line the log up to cut parallel with the bark.

So I cut parallel to the bark on my first face, and every time I roll it I realign my log using the headblocks (or toe board dependent on the mill setup) so the lumber comes off parallel with the new face. On Lynn's log backsawing that would mean leveling with the toe board to take a couple slices off the top face, a 180° degree roll and another level with the bark to take a couple slices off the opposite face, with then maybe another level with the toeboard to cut a shim to bring my central portion of the log back to something resembling heart centered... but when I roll to start removing material from that middle portion of the log I'm going to bring my saw in parallel with the bark again, then flip and come in from the other side parallel with the bark on the last face.

At the end given a log 10' long with a 1" taper I'd be wanting to see a square thats maybe 4x4 on one end and 5 x 5 on the other which contains all my pith material and any related heart decay. My aim is to recover as much wood as I can with a consistent cross section relative to the cambium layer, as in my experience that is the most stable alignment as it dries. And it puts my recovery of higher grade material up, as instead of my waste coming from high grade wood just under the bark it comes from low grade core material.


Mahoe Sawmills Supermill 2013 - YouTube

This movie Of a Mahoe operating would show a similar overall cut pattern to what I'd use from around the 2.35 minute mark. My technology may be different but the result is the same. Given that Mahoe  I'd come in from the top parallel to bark to around that point in the log, then do a shim cut relative to the heart for vertical taper, cut my middle third out, then another shim cut to bring taper back in line with the bottom of the log. And I'd pretty much do what hes doing there for left/right taper on each deck of coards that it made sense to do so on. (not worth the bother at the very top of bottom)

So is pine different? Or is it a translation thing, or a response to equipment capabilities, or is there some other reason? Always something new to learn and I gotta ask to do it...

thanks

[mike_belben]

Be sure to pause at 2:48 

;)

[Magicman]

SYP is very different and usually very cooperative when sawing framing lumber.  Just don't throw an 18 year old Plantation Pine log on the sawmill and expect it not to teach you a lesson.

[YellowHammer]

I always center the pith when YHRRQS to within an eighth of an inch with a tape measure.  A quarter inch is max acceptable, unless the log is a dog.  

Otherwie, I'm parrallel sawing the best faces, get the best boards first, which is absolutely critical for us, watch for spring or slip, and rotate the cant to target slip which causes curved edges (crook) but no bow.  Take boards being carful about grain balance, sapwood ratio, heartwood ratio and at some point, the pith gets centered as a general secondary effect to get the highest quality boards.  Much like if you eat corn on the cob, at some point, a cob is all that's left.

Reading stress from the log shape before the first cut, i.e. horns, swell, flare, etc is also critical.    

[mike_belben]

What are spring and slip?  What do they indicate?

[Busysawyer]

Spring would be the kerf opening up, either the ends or the middle lifting. Slip is when the board slips sideways on the cant. Slip is what I'm looking for, a crook can be edged straight but a bowed piece of grade lumber is junk.

[YellowHammer]

Exactly right.  It take careful watching but is critically important, especially since when a board is dried the effect is multiplied.  Rotating the cant 90° from spring which is some cases means the grade board is DOA off the mill will result in slip which means the board will retain its original value, except be narrower when edged.  Its the difference between a dead board and a high grade, flat as a pancake, board.  

One of the reasons we really shy away from buying green "really great wood" from other mills is that a large percentage of their boards are sawn without paying attention to this because they don't have to sell the dried product or eat the cost of a nice faced but otherwise poorly sawn board. 
 

[alan gage]

Deleted post - redundant

[mike_belben]

Man.   Lot to know. 

[Busysawyer]

Where it got a little tricky for me was grade sawing for wholesale.  Always opening on the best face of the log parallel to the bark as I was taught by the guys here.  I pull the first jacket board off and it lifts and bananas.  I know if I pull another its probably going to do the same thing but I also know its probably going to make select and better and pay me the same. Do I flip 90 and give them boards with better shape but a lower grade and get paid less? For me being a new guy trying to build a reputation with the buyers I flipped 90 and tried to give them a flatter board and took a chance on grade.  Now that I am milling for myself it's a easy choice.  I've really been trying to imagine what kind of stress a log has before opening it up. When cutting live edge slabs once the first cut is made you are pretty much committed.  For example, I bought this beautiful walnut tree from a homeowner awhile ago. The tree was about 26in diameter straight and clear for 18ft but it was growing on an angle. When I felled that tree I knew it was going to have a lot of stress and I knew it was going to be slabbed. When it came time to cut it I guessed what way it was going to bend. I guessed wrong and ended up with some really nice banana bowed slabs I sold at a discounted price. 

[Peter Drouin]

Having a board with spring will flatten when stuck. A slip or crook board will go back to a crook after a while. Even after you cut it to straighten it.
I don't make crook lumber. If one goes that way it goes into the chipper. ;D :D :D

[YellowHammer]

Different wood different target use.  A bowed hardwood board is of no value to a furniture maker and they will not buy it.  They will eyeball sight down the board and if it has bow, it goes back on the rack.  Before long, every board on the rack has been high graded, the only ones left are bowed, and the customer comes up to ask "Don't you have any straight ones??"  In order to make it sellable, it must be run on a jointer or facer, thinned down so the dimension has been reduced, and sometimes will not flatten at 3/4" so its dead.  Bowed boards result in table tops that aren't flat, furniture that won't edge join correctly, and other assembly issues.  A bowed board also indicates possible drying issues, uneven moisture content, or case hardening, all intolerable to high grade furniture makers.    

Boards with crook are edged on a straight line rip saw, jointer, or table saw, and will make flat glue up panels, and will not re crook because their edges are constrained by the other boards in their glue up or frame.  

As a side note, some straight line rips saws, especially ones with double feed chains, are adjusted where one chain runs a slightly different speed, so will intentionally put a slight amount of crook (called a "Hollow Cut") in boards to make a better and tighter glue joints when clamped.

Straight Line Rip Saw Features - Diehl Machines

Everybody must do what is right for their market.  Either way, reading stress and accounting for it in the log is of utmost importance.

[teakwood]

Everybody must do what is right for their market.  Either way, reading stress and accounting for it in the log is of utmost importance.

Very true, but on some type of woods it's just impossible to not get some bowed boards. I do harvest, saw, dry my own lumber and also make furniture's out of them, and i have never thrown away any board.  If a 8' long board isn't straight yes you can not use it for a table or top, but you can get rid of the bow and still get the measurements it was intended to by cutting it in half length. If you make a furniture you also need 4' 3' even 1.5' long boards, for the sides or slides. you can use it all! 

[Peter Drouin]

Very true Yellowhammer,  the market up here for the Pine and Hemlock in the building of houses and barns are worlds apart from what you do. 
I can put a bowed 2x4x16' on sticking and it drys straight. Hemlock is nice that way.


When I put a log on the mill I eyeball out to 16'. after that, out to 45' I use a tape, take ½ the tapper out, start with a 4" to 6" face,  Cutting W Pine and Hemlock.   

All the hardwood here is cut into grade and tree stakes, Long beams, trailer decking. or anything you want. :D :D

[PAmizerman]

I'm in the same boat as Peter.
I very rarely saw hardwood for grade.
In hemlock bow is better than crook

[Magicman]

I could almost say that I never saw hardwood for grade.  My customers are mostly landowners and farmers.  They want lumber for bridges, barn siding, and whatever other needs that may arise.  Logs are mostly salvaged from storm blowdowns, etc. and many times there is not a particular need for lumber at the time of sawing. 

[longtime lurker]

  In order to make it sellable, it must be run on a jointer or facer, thinned down so the dimension has been reduced, and sometimes will not flatten at 3/4" so its dead. 

Neah - its not dead, just being marketed wrong. Put them aside and when you've got enough run them through a moulder to finish at 9/16" or 1/2" with a VJ or shiplap or some other wall panelling profile. Bow doesnt matter because its that thin it will flex to where its nailed... and it will sell and be profitable. 
It aint dead here till you can see daylight through it, and dad will tell you thats a light feature :D

[crowhill]

MM, I assume by crook you mean crown?

Doesn't the crown come from the crook and those are ones used for floor joists or rafters, with the crown up😉

Should have read all comments before making comments, but that's what happens when you don't follow thru, you get twisted..

[YellowHammer]

We don't have a molder, I've thought about getting one, but I'm tired of buying machines. :D  If I could get one cheap.....

Siding, paneling, flooring are sold in this area for No1 and No2 common prices which is tremendously below my high grade prices.

[scsmith42]

Lots of great feedback in this thread.  In my instance,

1 - quartersawn lumber is ALWAYS pith centered in both planes.  We shoot for 1/8" accuracy.

2 - Full width slabs are ALWAYS pith centered in one plane (although sometimes we have to estimate where the pith is on logs that have forks on one end.  Accuracy between 1/8" - 1/4" depending upon the log.

3 - Timberframe beams, posts, etc are ALWAYS pith centered in both planes, typically within 1/4".  If we're milling FOH lumber, then we also will pith center the log.

4.  Grade lumber IS NOT pith centered.  Typically we will open the best face, square it up and then move faces as needed in order to yield the highest grade lumber.  Occasionally we will through cut until grade falls off - using the edger to square up the sides instead of squaring the cant.

5.  Framing lumber - well it depends.  If there is not much taper to the log then we will "eyeball" a pith center when squaring up the cant.  If there is a lot of taper in the log than we may center the pith in one direction only and mill the lumber so that the narrow part of the boards is parallel to the pith.  The objective here is to minimize slope of grain relative to the load bearing direction of the lumber.

6.  Barn wood - whatever nets the best yield.  We do not always center pith when milling barn siding but sometimes will center pith in one plane in order to minimize crook in the boards.

[JustinW_NZ]

Scsmith42 - I will just tick your list and go YES!

We quater saw a lot of tricky hardwoods and need to get rid of sap wood and pith so having things aligned is needed to not waste wood post sawmill.

Most softwood is generally eyeball levelish  

Cheers
Justin

[petefrom bearswamp]

as Gary Cooper once said "nope"

[OffGrid973]

So I honestly centered the pith today and happy with the results.  I will continue to do this for nice Hardwoods without branch sections as it gives a more consistent looking product.

Got a little wide at one point so had to chainsaw a bit, those black streaks shouldn't stay long on first sanding.



 

 

 

 

 

 

[kelLOGg]

I cut mostly 1" and 2" boards. If I don't center the pith part of my lumber will contain the pith and part will not. Doesn't that contribute to lumber crooking, bowing or twisting? I know the pith is not always straight and can wander but I thought it was always prudent to try to contain it in as few boards as possible. How can you do that without centering? What am I missing here? I understand when sawing parallel to the bark that there is no need to center the pith because the lumber will not contain the pith; it is part of the waste.
Bob