Cupping in Select boards

[Rick Akl]

I just received my first rough sawn lumber shipment of 8/4 hard maple. Some of the boards had a pronounced cup and some of the others had a slight crook. I have been searching online as to the permissible levels of these defects that can be included in the Select grade but have had no luck finding details. Does anyone have any suggestions?

[Jim Terrill]

Good question, I've never heard of grading based on cupping/bend/twist, only appearance.

[Howard Acheson]

Go here for grading info:

http://www.nhla.com/illustrated_guide/IllustratedGradingGuide.pdf?userid=

I also suggest you contact your supplier.

[Frank Drew]

Rick,

I rarely bought rough cut lumber that was dead flat and straight in all directions; that's a lot of the reason to buy rough cut, so that you'll have some material to trim to get your flat, straight piece. As an added bonus, rough cut is often a bit thicker than the stated dimension.

But if it the boards are too far off you should follow Howard's suggestion and call the supplier.

[Robert Reece]

Hi Rick-

I generally don't care what the wood looks like as long as I end up with full size once the wood is dressed. I always cut the pieces into roughly the size I need them before machining. This gives you the best possible chance to get the thickness you need.

That said, I would contact the supplier and just ask for their opinion of the situation.

I'd be a lot more concerned about the cupping then the crook. Many boards I get have some kind of crook or twist, but I rarely get anything with much cupping. That to me indicates some kind of moisture issue. Have you checked the moisture content?

[Frank Drew]

Your intended use will also determine whether or not the cupping is a problem -- if you're going to rip your 8/4 boards into 2x2 leg stock, then the cupping most likely won't be an issue at all.

[Rick Akl]

I'm going hold my tongue. I went back out to my warehouse to assess the wood again. Overall the batch is very good. The crook doesn't really bother me and the cupping is either better than I remembered it or it straightened out a little bit. I don't have a moisture meter as I have been stuck deciding between a pinned j2000 and some model of pinless meter.

There is some fine checking down the center of the board for 4-5 feet of a 10 foot board. I hope it will plane out.

The wood is for my workbench project so I may have to cut down and glue up the marginal pieces.

Thank you all for chiming in.

[Aaron Wingert]

Agreed Rick, sounds like a moisture (or drying) issue. The grade of the lumber is established at the mill at the time of production in most cases, long before it is air or kiln dried. Therefore, the nicest piece of lumber in the world can go straight to heck when it gets taken out of the pile and has a chance to do some moving. It is incumbant on the retailer to cull out boards that no longer meet the criteria for the quality of material the consumer expects when he spends big money on select grade materials. Having been in the lumber business, I'll tell you that all lumber dealers have to cull a certain percentage of even their best material periodically. It happens. You wouldn't be out of line in mentioning it to them to see if you can get a replacement, unless the board was in great shape when you bought it. What happens to it after it is out of their control is something they shouldn't be responsible for.

[william Burton]

The term used is rough sawn. The word rough is in there for a reason.

[Jim Terrill]

The term used is rough sawn. The word rough is in there for a reason.

I'm sorry, but if I get a board that has serious cupping or a bow or such, shrugging it off as rough sawn is not going to happen. Rough sawn refers to the finish, not the straightness of the wood.

[Chip Lindley]

Unless you specified dead-straight-flat, hand-picked lumber in your order to the supplier, you were at his mercy to select the boards to ship to you. Buying rough lumber sight unseen is kinda *iffy* at best. The most vocal and finicky buyer gets the best service. No doubt the supplier would accept returns, but you will probably pay the freight.

Select grade refers to boards with a certain amount of clear area on the best side of the board's surface. It has nothing to do with cup, bow or twist.

[Rick Akl]

Just found this passage in the NHLA Rule Card:

"When grading rough sawn lumber, defects such as checks, stain, and warp are not considered if they will surface out at standard surfaced thickness (S2S)."

and from the rule book in the FAS section, which is referred to from the Selects section:


"61. Warp and cup shall not be admitted if sufficient to prevent the
entire board from surfacing two sides to standard thickness in
accordance with the rules for lumber surfaced two sides, except
that slightly cupped or warped pieces 12" and wider are admitted
if they can be ripped to produce two pieces each of which would
grade FAS and then not contain warp and cup which would
prevent the ripped pieces from surfacing two sides to standard
thickness in accordance with the rules for lumber surfaced two
sides. The exception as to pieces 12" and wider shall not apply
to contracts for lumber in special widths 10" and wider."


SO...

If the defects are so severe that it would require excessive thinning of the board then it would not cut the mustard.

[Chip Lindley]

Rick, Thanks! That's new information for me. It sounds like your wood is within *Select* specifications after you joint and plane it. I buy *country* lumber that has been sawed and stored in barns, etc. I seldom buy anything better than No.1 Common for cabinet work from mills.

Another thought: the seller had no control over moisture, heat or cold that may have affected your wood after it left his premises on the truck.

[Brian Tymchak]

Agreed Rick, sounds like a moisture (or drying) issue.

My first thought as well. If it is severely cupped, etc., I would also consider that the wood may be case-hardened and will wig out on you when you rip it.

Brian

[Rick Akl]

I quit dilly dallying and ordered a j-2000 that was on sale for $208. Come Friday we'll see how uniform it is.

[Howard Acheson]

>>>>> and the cupping is either better than I remembered it or it straightened out a little bit.

Remember, the wood was shipped to you. It was obviously in some other somewhat different environment where it had acclimated. During shipping, it was again obviously in a different environment and wood will move when it finds itself in a new place.

Stack and sticker your wood for a few weeks and it will probably flatten out.

[Peter Quinn]

Hard maple is not the most stable of species. I have never seen 8/4 that wasn't cupped, and rarely is it very flat over its length after drying. I have turned a 2000BF pack of lumber looking for a few passage door stiles, something I could flatten over 80"-96" of length, and still come up empty or short. Unless they sent you some real twisted bananas, its probably standard fare. If you are making something that needs to be very flat over a great length and at a specific width, like door stiles for instance, and you are ordering by mail, you must be very specific of your needs and develop a strong relationship with the supplier picking the lumber.

Lumber grading relies a lot on the judgement of others, where as wood working relies primarily on the judgement of the individual working the wood. This is why I prefer to purchase wood in person if at all possible, as the general grade can be way too vague for certain projects.