The Forestry Forum is sponsored in part by:

iDRY Vacuum Kilns


Forestry Forum
Sponsored by:


TimberKing Sawmills



Toll Free 1-800-582-0470

LogRite Tools



Norwood Industries Inc.




Your source for Portable Sawmills, Edgers, Resaws, Sharpeners, Setters, Bandsaw Blades and Sawmill Parts

EZ Boardwalk Sawmills. More Saw For Less Money!

STIHLDealers.com sponsored by Northeast STIHL


Woodland Sawmills

Peterson Swingmills

 KASCO SharpTech WoodMaxx Blades

Turbosawmill

Sawmill Exchange

Michigan Firewood, your BRUTE FORCE Authorized Dealer

FARMA


Baker Products

ECHO-Bearcat

iDRY Wood Lumber Vacuum Drying for everyon

Nyle Kiln Dry Systems




Author Topic: Lumber Tollerance  (Read 951 times)

0 Members and 1 Guest are viewing this topic.

Offline whittle1

  • member
  • *
  • Posts: 35
  • Age: 65
  • Location: Malvern, AR
  • Gender: Male
  • I'm new!
    • Share Post
Lumber Tollerance
« on: June 03, 2019, 09:49:43 AM »
What is considered acceptable tolerance when cutting lumber on an LT40 mill without accuset. I'm looking for +or - from board to board and also any taper over a 12' length. I know even in a high end production mill, I'm talking mills that produce 500k to 700k rough bdft a day has variations in size.
 Thanks Wayne


Offline Magicman

  • Senior Member x2
  • *****
  • Posts: 38211
  • Age: 76
  • Location: Brookhaven, MS
  • Gender: Male
  • A "Traveling Man"
    • Share Post
    • Knothole Sawmill
Re: Lumber Tollerance
« Reply #1 on: June 03, 2019, 09:58:43 AM »
When I am sawing any significant variation from the mark will be from the log/cant moving, not from me nor the sawmill.  My job is to read the log and try as best possible to open, orient, and turn while sawing.
Knothole Sawmill, LLC     '98 Wood-Mizer LT40SuperHydraulic   WM Million BF Club Member   WM Pro Sawyer Network

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

Offline luap

  • Full Member x2
  • ***
  • Posts: 195
  • Location: western Upper Penninsula
  • Gender: Male
  • Not as good as I once was
    • Share Post
Re: Lumber Tollerance
« Reply #2 on: June 03, 2019, 07:20:02 PM »
When I have purchased lumber from a large commercial mill as you describe every piece was within  + 1/4 -0, thickness and width. From your own mill dimensional tolerance could be dictated by end use and or are you selling to the public. Regardless of the  brand, model mill how fussy are you or is that just good enough? 

Offline gdaddy01

  • Full Member
  • **
  • Posts: 51
  • Age: 63
  • Location: altha fl.
  • Gender: Male
  • I'm new!
    • Share Post
Re: Lumber Tollerance
« Reply #3 on: June 04, 2019, 09:36:01 PM »
I am putting up some store bought 2x8's that are 7 inches wide . lots of 2x4's that are 3 1/4 to 3 3/8's seems to be getting worse , I know that was not your question , but I think we try to do better than that . I feel like the ones I read about on here do .

Offline Cartwright

  • member
  • *
  • Posts: 37
  • Location: Roxboro nc
  • Gender: Male
    • Share Post
Re: Lumber Tollerance
« Reply #4 on: June 04, 2019, 10:12:21 PM »
Any variation in thickness greater than 1/4" shall be classed as mis cut. 
Wood-Mizer LT50HDD47-RA
Eg 200 twin blade edger 25hp gas
Volvo L30 compact  wheel loader
Ford CL65 skid steer
'09 F250 Super Duty Powerstroke  deleted and tuned
Stihl ms391, 390, 029

Offline crowhill

  • Full Member x2
  • ***
  • Posts: 204
  • Age: 71
  • Location: SE VERMONT
  • Gender: Male
    • Share Post
Re: Lumber Tollerance
« Reply #5 on: June 07, 2019, 07:22:33 AM »
What surprises me with EWP is the variance after it has dried. Seems some boards can shrink a 1/4, others not so much. I have a small camp I built 55 years ago with EWP that had air dried 2 years. As I put the sheathing on I used a pry bar to keep the boards really tight before nailing and now there places where the spacing is over a 1/4 between them but not all boards have shrunk. 
TimberKing B-20, Kubota M-4900 w/FEL with tooth bar, hyd thumb and forks, Farmi winch, 4 chain saws.

Offline etroup10

  • Full Member x2
  • ***
  • Posts: 198
  • Age: 27
  • Location: Richfield, PA
  • Gender: Male
  • NHLA 187th class
    • Share Post
Re: Lumber Tollerance
« Reply #6 on: June 07, 2019, 11:03:52 PM »
Depends on the thickness of your lumber, for 4/4 and 5/4 +1/4" is acceptable. There are higher tolerances for thicker lumber. There is no tolerance for thin lumber.  If you are talking tolerances for width, 90% of your lumber should be full width and up to 10% can be up to 1/4" shy in width. This is all for green lumber. When it comes to dry lumber you are allowed 1/4" shy in width on all lumber and up to 1/2" shy in width for 10% of it. This is according to the NHLA grading rules. if you are selling retail, i would say to keep your widths full width just for the customers sake. 
NHLA 187th class, lumber inspector. EZ Boardwalk 40 with homemade hydraulics; Gafner Hydraloader; custom built edger, Massey Ferguson 50E, American Sawmill 20" Pony Planer; Husqvarna 55 Rancher

Offline DMcCoy

  • Senior Member
  • ****
  • Posts: 672
  • Location: NW OR
  • Gender: Male
    • Share Post
Re: Lumber Tollerance
« Reply #7 on: June 08, 2019, 07:08:39 AM »
I bought @100 16' 2x6 PT a couple of years ago.  Varied from 6 3/8" to 6 5/8" with a couple of pieces worse than that. I was surprised and this is after it was planed(wow!)

This might get a bit wordy - forgive me, I do get to the point eventually. My mill is homemade -4 post horz. bandmill. I don't have any counter balance(springs or weights) to help hold the saw head up, and I used UHMW wear strips to keep the saw head tight to the vertical posts.  I used the UHMW because I wanted the band to remain parallel to the bunks. I wanted that weight to keep the saw head lifting chains tight, and remove any slop that might be created by the UHMW rubbing the post. I still have one spot that it gets a little sticky on the way down, around the 9" mark, so I drop below that and then come back up to the mark, the idea is to have the lift chains tight and not have it fall as it cuts from vibration.  When my mill is adjusted properly and the blade is sharp(outside corner of the teeth sharp) I'm less than 1/16" between boards.

Imo it is worth the time and money to get your saw cutting consistent what ever that takes.  It will more than make up for it at the planer.  Look for and eliminate slop methodically.  Once I get my mill tuned up it is always dull band that mess me up.  Banging heavy logs during a flip usually ends up in a tune up I have found.  If the log is extra large I will take it off the mill, flip it and set it back.  My 2 cents fwiw.   

Offline WDH

  • Forester
  • Administrator
  • *****
  • Posts: 28924
  • Age: 65
  • Location: Perry, GA
  • Gender: Male
  • April 1998 - August 2008
    • Share Post
    • hamsleyhardwood.com
Re: Lumber Tollerance
« Reply #8 on: June 08, 2019, 07:17:54 AM »
If you plane a lot of lumber, you become intolerant of tolerance. 
Woodmizer LT40HDD35, John Deere 2155, Kubota M5640SU, Nyle L53 Dehumidification Kiln, and a passion for all things with leafs, twigs, and bark.  hamsleyhardwood.com

Offline Don P

  • Senior Member x2
  • *****
  • Posts: 5714
  • Location: Southwestern VA
  • Gender: Male
    • Share Post
    • Calculator Index
Re: Lumber Tollerance
« Reply #9 on: June 08, 2019, 08:23:04 AM »
What surprises me with EWP is the variance after it has dried. Seems some boards can shrink a 1/4, others not so much. I have a small camp I built 55 years ago with EWP that had air dried 2 years. As I put the sheathing on I used a pry bar to keep the boards really tight before nailing and now there places where the spacing is over a 1/4 between them but not all boards have shrunk.

I bought @100 16' 2x6 PT a couple of years ago.  Varied from 6 3/8" to 6 5/8" with a couple of pieces worse than that. I was surprised and this is after it was planed(wow!)
These two are related. The part of the shrinkage table we all gloss over is "average" shrinkage values. Every board is an individual and on top of that it is probably not exactly radial or tangential grain, so from green to dry each board shrinks differently. Lump the shrinkage from 100 boards together and divide by 100 and there is the average.
PT lumber is usually made from dried, milled lumber that is then rewetted by the treating process. Unless it is KDAT, kiln dried after treatment, what you get at the lumber yard is basically green lumber so it has swelled differently for each board around that average. It will dry back to something close to the milled dimension but it won't be exactly on tolerance.
My mill is not very accurate and probably will never be. It will improve but will never be as tight as a band much less a swing blade. I worked in a shop years ago where our molder could not tolerate more than about 1/8" variation in infeed thickness. I got in the habit of looking over the stack and if the wood came from a woodpecker mill it went through the planer first. When I bought my mill the next piece of equipment I bought was a planer. When I make a thick or tapered board it gets set over to go through the planer. I try not to send miscuts further downstream. A few hours spent correcting miscuts will send you back to tightening up the mill.
A laborer works with his hands
A craftsman uses his brain and his hands
An artist uses his brain, his hands, and his heart

Offline moodnacreek

  • Senior Member x2
  • *****
  • Posts: 1280
  • Location: Orange County NY
  • Gender: Male
  • Sawin by the notches
    • Share Post
Re: Lumber Tollerance
« Reply #10 on: June 08, 2019, 08:24:41 AM »
What surprises me with EWP is the variance after it has dried. Seems some boards can shrink a 1/4, others not so much. I have a small camp I built 55 years ago with EWP that had air dried 2 years. As I put the sheathing on I used a pry bar to keep the boards really tight before nailing and now there places where the spacing is over a 1/4 between them but not all boards have shrunk.    That is because it is dryer where installed than where stickered.


Share via delicious Share via digg Share via facebook Share via linkedin Share via pinterest Share via reddit Share via stumble Share via tumblr Share via twitter

xx
wannabe lumber miller/Husq 353/lumber jigs/log arches and spruce

Started by jimbarry on Sawmills and Milling

13 Replies
1441 Views
Last post August 23, 2013, 06:39:18 AM
by jimbarry
xx
Dimensional lumber / Green Lumber building forum?

Started by grweldon on Technical Support Topics

10 Replies
1986 Views
Last post December 03, 2012, 02:59:57 PM
by mad murdock
xx
Cutting beams and lumber with a Haddon lumber maker.

Started by richhiway on Sawmills and Milling

17 Replies
9747 Views
Last post April 29, 2014, 05:02:35 PM
by richhiway
xx
Vintage lumber yard, built to air dry lumber

Started by low_48 on Drying and Processing

0 Replies
692 Views
Last post May 08, 2016, 11:30:07 PM
by low_48
 


Powered by EzPortal