iDRY Vacuum Kilns

Sponsors:

How to size my lumber

Started by welderskelter, April 11, 2021, 04:53:58 PM

Previous topic - Next topic

0 Members and 1 Guest are viewing this topic.

welderskelter

 Ok...... Hear is my deli ma I have been sawing all my dimension lumber  to nearest inch or correct size. Meaning 2 by 4 and 1 by 4. Now it just seems as I would be able to get more lumber if sawed smaller. 1and a half and  3/4 in. You know the planed lumber size. What do yall do when you want to do this ? Is there a different scale for cutting the smaller 2x4s and 1x4s, and do you guys figure the .042 for the width of the blade or just forget it. This lumber will be for my  projects.  Just curious. Right now I just have an aluminum yardstick from Menards for my measuring stick. Thank you.

KenMac

I'm sure others with more experience and ability to explain will chime in soon, but since I'm here I'll give it a try. Fact is you can saw whatever width and thickness that suits your need for your own use. If selling lumber I always check with the customer to confirm, in writing if possible, their exact preference. As far as your scale there are scales available from Cook's Saw Mfg. as well as most other saw manufacturers that make sawing from a scale much simpler. For example, Cook's 4/4 scale drops 1 1/8 inch to meet NHLA guidelines and requirements. I'm not sure about others, but I'm sure they are similar. In any case you must allow for kerf which is generally considered to be 1/8" even though it might not be exactly that much. 1/8" simplifies math greatly. I hope this helps and doesn't confuse you more. 
Cook's AC3667t, Cat Claw sharpener, Dual tooth setter, and Band Roller, Kubota B26 TLB, Takeuchi TB260C

WV Sawmiller

   Lumber sizes should be based on final expected use. Dimensional lumber (1.5"X3.5" for a finished 2X4) started as a full size  board then was dried and planed to the smaller, final sizes. I normally saw full sizes too but can saw any size to match what the customer wants. If he wants to match store bought dimensional lumber I'll saw it 1-5/8" X 3-5/8" or whatever he wants. I use 1/8" as my kerf sizes, saw the cant to the final board size then on the final cut I start at the appropriate mark off the attached cheat sheet below so I end on a finished board and save myself a cut off each cant.

   BTW - I mostly saw for others using their logs so I confirm with them the size they want and saw accordingly. Often the customer is my offbearer and on the first finished board I'll hand him my tape and ask "Is that what you want" and get his blessing or change accordingly. Very rarely do they change their mind once they see it.
Howard Green
WM LT35HDG25(2015) , 2011 4WD F150 Ford Lariat PU, Kawasaki 650 ATV, Stihl 440 Chainsaw, homemade logging arch (w/custom built rear log dolly), JD 750 w/4' wide Bushhog brand FEL

Dad always said "You can shear a sheep a bunch of times but you can only skin him once

Don P

I think I uploaded the "official" green lumber size chart into my gallery awhile back.

Here it is;


 

welderskelter

Thank you WV. I think your cheat sheet is what I am looking for. Will save a lot of figuring.  Thank you again.

WV Sawmiller

   I keep a printed copy in a gallon ziploc bag under magnets on the inner lid of my control panel on my mill so it is handy to refer to when I need to do so. 
Howard Green
WM LT35HDG25(2015) , 2011 4WD F150 Ford Lariat PU, Kawasaki 650 ATV, Stihl 440 Chainsaw, homemade logging arch (w/custom built rear log dolly), JD 750 w/4' wide Bushhog brand FEL

Dad always said "You can shear a sheep a bunch of times but you can only skin him once

welderskelter

Thanks to you I do too. Thanks again

jovol

Sawmill Cut Intervals - Google Sheets

I made that cheat sheet for myself when I didn't have setworks. Sheet 2 is the one I printed out and taped to the underside of the control cover.

Accuset 2 is basically cheating, so much brain space opened up to focus on other things  :D
2017 LT50 wide, stihl ms362 & ms660, echo cs7310, Logrite fetching arch, 2000 New Holland LS180, Ford 6.0, kubota L48, kubota KH-70, Ford F800 8.3

samandothers

OK, so help me out here on the worksheets.  I know that you want to produce what you or the customer wants. What I think I am seeing above maybe 2 sheets with to help account for blade thickness when cutting (WV's and joval's) and one sheet to help account for shrinkage (DonP's). 

WV's - appears to be if you want a board of a certain thickness add an 1/8" to account for the saw kerf, example 1" board add 1/8" to allow for the saw kerf so to get 2 boards you'd need 2 1/8" of thickness to start.  Thus this sheet helps when sizing your cant to produce the 1" green boards.

Don's posting appears to be what to cut green wood at to allow drying shrinkage to obtain a certain dimension of wood.  

jovol's appears to be similar to WV's but allows a 1/16 inch for blade kerf.

Though I currently follow the process WV uses, if you wanted to be more 'accurate' would not the process/sheet one uses need to account for the blade kerf and shrinkage? 

WV Sawmiller

Sam,

   Yes it would if you knew the exact shrinkage rates for each species of wood you were cutting and the conditions under which it is dried. I bet any shrinkage rates listed anywhere are averages and actual results may vary from log to log and by different processes. I.e. Is shrinkage in lumber air dried to a certain moisture content exactly the same as that same lumber kiln dried to the same MC? Does vacuum drying produce the same shrinkage rate as heat drying or air drying? That is what planing dried lumber is for - to get every board to a predetermined final size.

   My process leaves the customer with a predetermined size of wood at the time I cut it. If he wants to allow more for shrinkage he just tells me how much more to oversize and I'll cut it that size. I put that shrinkage burden on the customer not on me the sawyer. Once I cut and leave the lumber anything else that happens is the customer's responsibility as I can't control it. Remember - we are talking about trying to cut green lumber to match a size of lumber that was cut green, dried then planed to a precise thickness.

   I do the same with metal in the log and if I hit it the customer pays for the blade. I don't metal detect then if I miss a nail or spike absorb the cost. I certainly don't want to absorb more risk and responsibility for things beyond my control.
Howard Green
WM LT35HDG25(2015) , 2011 4WD F150 Ford Lariat PU, Kawasaki 650 ATV, Stihl 440 Chainsaw, homemade logging arch (w/custom built rear log dolly), JD 750 w/4' wide Bushhog brand FEL

Dad always said "You can shear a sheep a bunch of times but you can only skin him once

Magicman

samandothers, don't expect a "one-size-fits-all" perfect sawing pattern.  Your blade thickness & set matters, species matters, whether quarter, rift, or flat sawn matters, the age of the tree/log (how much juvenal wood) matters, heartwood vs sapwood matters, how long since the tree was alive (age of log) matters, and then your sawing accuracy matters.

Any one of the above "laundry list" can affect shrinkage and sometime you are sawing a combination of two or more within the same log.  Establish your sawing dimensions that fall within established parameters and stay consistent.
Knothole Sawmill, LLC     '98 Wood-Mizer LT40SuperHydraulic   WM Million BF Club Member   WM Pro Sawyer Network

It's Weird being the Same Age as Old People

Never allow your "need" to make money to exceed your "desire" to provide quality service.....The Magicman

alan gage

I use the 6/4 scale from Cooks which gives me a 1 5/8" thick board off the mill.

I usually cut wide and edge to target width after drying.

Alan

Timberking B-16, a few chainsaws from small to large, and a Bobcat 873 Skidloader.

Bigly

one way to go if you want to make a log go a bit further and don't want to have to think very hard or consult your cheat sheet much is to saw to 7/8".   Once you get to your 4th face in the cant go to the nearest inch + 7/8 (say 9-7/8" for example), then just drop an inch each cut, which, allowing 1/8" for the blade gets you a 7/8" board every time, so 9-7/8, 8-7/8, 7-7/8, etc all the way down to 0-7/8."

When I cut for myself I saw 2x to 1-1/2 because it's handy if you want to use joist hangers.  I used to saw to 2" but got sick of planing or chiseling out the ends for the hangers.  Actually, now that I've got a computer I cut to 1-9/16 so it shrinks to 1-1/2" but that's not really necessary.  I cut them to a full 4 or 6 or whatever and usually use them like that but if I want to get fussy I'll let them dry/shrink/warp, then put them back on the mill and edge them to 3-1/2, 5-1/2 etc.

happy cutting!

samandothers

I understand the need to pick a dimension to use beyond your desired finished dimension to account for blade kerf.  I was just thinking it should be an amount beyond blade kerf to allow for shrinkage.  Seems related to the idea 4/4 is different for hardwood versus soft wood.  I too cut oversized and then dress to usable dimension.  

Thanks for the responses and the bit of deviation from the OP's query.  

WV Sawmiller

Sam,

   I think it was the MM who mentioned in a post a while back one good feature in us sawyers cutting dimensional lumber to match factory sizes is the difference is not normally going to be enough to be noticeable or affect the end use. When nailing framing I doubt 1/8" or so would even be noticeable to most of us.  ;)
Howard Green
WM LT35HDG25(2015) , 2011 4WD F150 Ford Lariat PU, Kawasaki 650 ATV, Stihl 440 Chainsaw, homemade logging arch (w/custom built rear log dolly), JD 750 w/4' wide Bushhog brand FEL

Dad always said "You can shear a sheep a bunch of times but you can only skin him once

Magicman

I normally saw 1/16th" over so if the piece shrinks 1/8th" it would only be 1/16th" smaller than factory dimension which is negligible.  I have seen factory lumber vary more than that. 

The real key is being consistent and sawing your lumber the same size.
Knothole Sawmill, LLC     '98 Wood-Mizer LT40SuperHydraulic   WM Million BF Club Member   WM Pro Sawyer Network

It's Weird being the Same Age as Old People

Never allow your "need" to make money to exceed your "desire" to provide quality service.....The Magicman

Joe Hillmann

Totally depends on intended use. I use most/all of my lumber rough sawn so I don't worry about leaving room to plane it.  I do a lot of milling by cutting it at the inch mark and the final material ends up being 1 kerf less.  But I also do some milling where I take the kerf into consideration and mill it so the final board is the actually inch thickness.  I have also over sawn material to compensate for the kerf and drying shrinkage.

With a band mill that cuts straight you can get more 2x4's out of a log by milling them to be 1 1/2 x 3 1/2.  But I tend to cut them at 2x4 and loose the saw kerf so I end up with 1 7/8 x 3 7/8 or so.

Larry

Quote from: WV Sawmiller on April 12, 2021, 02:26:38 PM

  Yes it would if you knew the exact shrinkage rates for each species of wood you were cutting and the conditions under which it is dried. I bet any shrinkage rates listed anywhere are averages and actual results may vary from log to log and by different processes.
Shrinkulator

Note shrinkage is almost double for tangential.

Folks have different viewpoints about how much size difference is acceptable in framing lumber.
Larry, making useful and beautiful things out of the most environmental friendly material on the planet.

We need to insure our customers understand the importance of our craft.

Thank You Sponsors!