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Do you make shim cuts to increase the amount of grade lumber?

Started by etroup10, July 17, 2015, 11:42:31 AM

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etroup10

When cutting rr ties or other cants, do you make shim cuts on your final two sides to get the most grade lumber?

Whenever I saw a log I cut my first two sides with a 6" face then take off boards down to where the grade drops off. On the other two sides I will count boards back from my final cut for the cant to determine where I open up the log. This method has worked out pretty well for me but then I stopped by a big mill that cuts around 10000 bdft a day. Instead of setting up their final two sides, they will just try to cut a 6" face, take boards till grade drops off, then make a shim cut to reach their final cant dimension. It just doesn't seem efficient to me. Sometimes the shim can be anywhere from 1/8" to 3/4". To me it seems the extra time to cut the shim wouldn't be worth the little bit of extra grade lumber gained, and there is no guarantee for additional grade lumber. I was also thinking it may be different since they have a larger kerf and therefor more grade lumber would be turned into sawdust.

Just wanted to see what everyone on here thought and how they did things.
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

Ljohnsaw

Sorry, no input but a question.  I've seen this mentioned before and don't quite get it.  What do you mean by "when the grade drops off".  To me, it would seem that the quality of the wood just get better the deeper you go.  I'm assuming you are taking one tie from the center and producing other lumber from the sides, but don't quite get the grade thing.

Thanks for your patience on a rookie.
John Sawicky

Just North-East of Sacramento...

SkyTrak 9038, Ford 545D FEL, Davis Little Monster backhoe, Case 16+4 Trencher, Home Built 42" capacity/36" cut Bandmill up to 54' long - using it all to build a timber frame cabin.

Magicman

The commercial mill may be sacrificing quality on a few boards to reach their quantity numbers.  That may be more efficient for them.  You, on the other hand, can take a few minutes more on a cant and squeeze out all of the higher quality lumber.

Your minute may only affect your time.  Their minute probably affects several paid laborers time.
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

etroup10

@ljohnsaw, When your sawing a log, the clearest boards(fewest knots) will come from the outside of the log. The grade of a boards is primarily dependent on the amount of knots and their location. So for instance you have a log that shows no knots on the outside. You would first take off your slab and there is a good chance you have a clear face(no knots). So then you cut a board, this will be your highest grade board because it is knot free wood. As you keep cutting boards it is more and more likely to hit a knot which lowers the grade of the board which is what we mean by "grade dropping off". A knot is where a limb used to be. Since trees grow on the outside, they grow around the limb creating knots inside the tree. If a limb dies and falls off or gets knocked off by some other force, the main trunk will continue to grow around where the limb was and after time you can't tell there was a limb there. So when you saw, you will get clear lumber to where that limb stopped growing. The amount of knots you get in a log and how deep they are is dependent on a lot of things, like location of the log in the main stem(higher up essentially means more knots and butt logs usually have less and deeper knots which means more clear lumber), the type of tree and the environment in which it grew(more open=more knots, competition with other trees=less knots)
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

Glenn1

Etroup10,  That is a great explanation and I appreciate the time taken to write it.
Vacutherm IDry, Nyle 53 Kiln, New Holland Skid Steer, Kaufman Gooseneck Trailer, Whitney 32A Planer

Jim_Rogers

I believe that when a hardwood tree branch is in the shade, of other trees or of other branches of its own, they die. and after they die they sometimes fall off. I believe this is called "shade off". As mentioned the older the tree the smaller the knot if they fell off early in the tree's life. And closer to the center of the tree.

With softwoods like pine, the branch sometimes doesn't fall off and you get black knots from the branch after it has died. Sometimes that black knot will "heal over" and not show on the trunk of the tree. Depending on lots of circumstances of where it grew.

With white pine, in my area the boards can go from nice clear boards, to boards with black knots, to boards with red knots when the branch was alive.
If a knot has a portion of the ring around it that is red, not black then it is considered a red knot. A black knot can and most times is considered a "hole" as it will, most likely, fall out during machining.

So the quality can go from great to bad to better as you get deeper into the log. You need to "read" the log and see what's happening as you get closer to the younger wood in the middle.

Jim Rogers
Whatever you do, have fun doing it!
Woodmizer 1994 LT30HDG24 with 6' Bed Extension

Ron Wenrich

I cut millions of feet of hardwood grade.  A lot depends on the log.  Some logs it's worthwhile to take the shim cut, some it's not.  You get to know how to read logs after a couple of million bf.  If you're on butt cuts, your grade isn't going to drop off that quick.  When it does, you have to figure if the back side of that clear face is going to be a 1 or 2 Com.  If it's a 1 Com, you make money as F1F, if it's a 2 Com or lower you lose.   

If you're cutting 2nd cut logs, you'll run into spots where you are at a 1 Com face.  What are the odds you go to a 2 Com back?  You're playing with risk/reward here.  Is it worth the risk of pulling a board that results in a back that is too low of quality?

I added shims to my stack count if my initial cut would yield too large of a slab.  If the slab yielded a wider face, I figured I made out in the grade in most counts by having that wider face and gaining the volume in better grade then going and taking a slight shim cut. 

I used a computerized setworks and had my stacks built in for the when I hit a certain face.  I pretty much knew what my cant was going to be, and I built my stack.  When you hit your first set, the log is brought into position.  You can see pretty much how deep the slab will be with a laser or shadow light.  If it is too light, then you can either hit a set or take a shim.  But, I always made sure there was going to make my cant at least ½" heavy where I ended.  That way my shim cut wouldn't be brushing the cant.  If you brush against the log, you'll push your saw and not saw any wood.  When I built the stack in my head, I sawed the same way.

The other times that I would cut shims is when I turned back to a face.  That was usually done on big logs.  When you turn back, you will have tensions in the log that may give you a badly sawn board.  It may have a thick end or something to that effect.  I always took a shim cut to square up the face.  That isn't always cost effective because now your back side is ½" closer to the defect you were trying to avoid.

One thing I normally did was try not to saw too much 2 Com.  There may be some exceptions, but I always found that throwing 2 Com into cants or ties was cost effective, and gave me much better grade loads to my customers.  I never lacked for customers during good times or bad. 


Never under estimate the power of stupid people in large groups.

beenthere

Jim
Helpful explanation, but "shade off" is a term I'd never heard of before. New one to add to the "list".
south central Wisconsin
It may be that my sole purpose in life is simply to serve as a warning to others

woodmills1

My trim cuts are geared more to what product I need out of the logs I have.  First,  I have enough lumber, both soft and hard on stickers for my on going customers.  So, say I get an order for 2x10x16 oak trailer deck, another quality 4/4 board will take a year or 2 to sell so trim cuts are ok to give me 10 inch faces I can get paid for this week.   My dream is always to have 2 jobs working, one for 2 inch and one for 4/4 so I can use more of each log.   Ideal would be 2 random width jobs at 2 different thickness.
James Mills,Lovely wife,collect old tools,vacuuming fool,36 bdft/hr,oak paper cutter,ebonic yooper rapper nauga seller, Blue Ox? its not fast, 2 cat family, LT70,edger, 375 bd ft/hr, we like Bob,free heat,no oil 12 years,big splitter, baked stuffed lobster, still cuttin the logs dere IAM

Nomad

     I'll make a trim cut sometimes.  For example, if I need a 6" opening face and misjudge, getting a 5" face instead.  I'll cut a ¼" to get me where I want to be.  Sure beats throwing away a whole board the customer can't use.  However, I've never tried doing that cutting for grade.
Buying a hammer doesn't make you a carpenter
WoodMizer LT50HDD51-WR
Lucas DSM23-19

mesquite buckeye

Manage 80 acre tree farm in central Missouri and Mesquite timber and about a gozillion saguaros in Arizona.

Oddman

Any sawyers out there willing to shed some more light on this subject?? Very interesting to a new sawyer like myself.

RobS

I cringe everytime I see a youtube video with someone taking a 5" thick slab on the first cut of the log.  I would always aim for getting as small of slab as possible, while still  ending up with an even number of boards by the time I reached the blocking of the log center.  Two main reasons are 1 less pass on the head rig, and usually better boards  further from center.  

(Sel, FAS, F1F, 1com, Blocking, 2com, 1com, FAS, Sel)

A clear 4" x 6' board can be a Select and get close to FAS price per bft.  So it is take  2bft at $1 a ft, or make 10cents in chips.

If I were to fill 2 chip trailers a day, my boss would have canned me.  We sawed 18-24,000bft of grade hardwood a day.  2 loads of lumber, 1 load blocking, 1 load chips, 1 load sawdust.  (roughly).
John Deere 5310 w/ FEL forks, Husky clone 372xp, Husky 455, 240, woodshop and forge.

120th class 1996 NHLA inspection school.

moodnacreek

Sawing 'knotty pine' , there is no grade so the 3rd and 4orth slabs are taken so the width or last board thickness is set and a shim cut would be a mistake correction and result in a lost board. When sawing for grade or some special cant the sawyer will do anything to get the desired lumber and the more tricks he knows the better.

nativewolf

great insight, thanks to @oddman for restarting.  Really enjoyed @Ron Wenrich comments, as always.
Liking Walnut

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