I’m an amateur wood worker looking for some advice on a desk design I have in mind. I want a work surface size of 60″x34″ and I am dreaming of using some exotic hardwood like wenge, mahogany, or perhaps bubinga. I want a strong and stable feel so I’m looking mostly at 8/4.
The key feature (or perhaps pitfall as I’ve learned) is that I want to make the top out of one solid piece. I realize the cost will be great and want to do as much research as possible to achieve success.
I’ve visited several lumber yards, Rockler store, Woodcraft Store etc and I’ve found some nice wood that would look nice. One gentleman overheard my plan today and quickly advised against the 1-piece design. According to him, even a 8/4 board will cup and warp over time; even in a stable climate controlled environment. He advised no amount of reinforcement or engineering would keep the wood from warping and eventually I would be working on a curved top desk. He advised gluing up and butt joining several 2-3 inch wide pieces.
I’m not anxious to do that since I don’t own a jointer or planer. However; I would be willing to invest in that equipment if my one piece plan is definitely doomed to failure. Also I really love the color/texture of wenge and can’t find any 1 piece planks that size so joining would be my only option.
What do you guys think?
Replies
"Quarter-sawn" boards, where the grain direction is perpendicular to the width of the board, are not likely to cup, but are almost impossible to find in many species. Boards "cup" towards the side that was closest to the bark or outer edge of the log from which they were cut, but some species have a greater tendency to cup (with moisture changes) than other species. There have been articles in FWW and other woodworking magazines on wood stability that you might look for. You might also look for books on wood and lumber that might have a chart listing the relative (tangential?) stability of various species. Many finishes slow the movement of moisture so finishing all surfaces of a table top often will reduce the amount of movement from season to season by reducing the moisture change, but will almost never completely eliminate movement.
If a wide board is ripped into several narrower pieces and then glued together, you will find some people fervently believing that the grain direction should be alternated between boards, and others equally convinced it doesn't matter if the grain is alternated or not. I'm not going there.
Whatever you do, it still is necessary to allow for expansion and contraction across the width, which is a separate issue from cupping. It's always frustrating for me that wide boards/slabs won't behave the way I would like them to. Good luck.
gte33f,
Well I have about ten 22 inch wide boards which should be pretty cup shaped according to myth.. they' re flat as a pancake..
Do have one 23 inch wide board that managed to cup but I solved that problem by placing weights on it and letting it stay that way for a couple of years, it's pretty flat now. By next year it should be flat enough to use on the bar I planned for it..
About a decade ago there were some 48 inch wide planks laid down on a floor and last I saw they were still flat..
If you look many old antique tables and desks were made with a single piece of wood and they haven't cupped in a couple of hundred years..
Not all wood will cup! Sometimes if it does cup you can flatten it and sometimes no matter what you do even glueing narrow strips of wood together things will still cup..
In my personal experience (and I've used these woods that you're talking about) - both wenge and mahogany are good candidates for 1-piece tops that will stay flat. If they are dry and flat, they will likely stay that way. Bubinga is a bit more capricious. Maybe this is just a question of suppliers. But I'd be wary of the bubinga. Padauk is also a great wood for wide stable slabs.
Go for it.
David Ring
http://www.touchwood.co.il/?id=1&lang=e
There is a current thread about this same subject, it is titled " widest boards recommended for glue up" or something like that. A lot of different opinions, check it out. I am not sure if you could find Wenge in that size, but it would be absolutely beautiful. I would hate to think of the cost of such a board.
My first thought was that there is more chance of you being machine -gunned by Jane Fonda than of you getting a piece Wenge of those dimensions, not to mention one free of defects.
The next thought was that certainly there are slabs of that size to be had in various timbers, so the trick is to find a board that was properly sawn initially, stacked and dried.Properly sawn = straight and without including center pith etc.Then it would need to be free of undesirable defects like cracks, shakes, loose knots , foreign bodies,and the like.
The next thought was that having found the board, it would need to be straight enough to enable you to clean it up nice and flat to dimension.
I then thought of what support this top will get from the design construction. If it is to be attached to a suitable framework, with allowance for cross grain seasonal movement, it should not cup or crack-so your "friend" at the timber yard was dishing out mis-information.Also the finish and the final resting place may influence matters i.e if it is be in your castle right next to twenty four hour roaring fires it could crack .
If it were me I would prefer to make up a top from say three selectd prime boards, but I do not know what design style you have in mind,but suspect it may be unconventional since you want a desk top so thick.Maybe it can double as a bench top? (;)
Can you post a picture of the design you have in mind?
Check out http://www.hearnehardwoods.com . They are located in Oxford,Pa. Last time I was over there they had 10/4 and 12/4 slabs of bubinga that were 40 to 50 inches wide by about 12 feet long. This was some beautiful lumber! They usually have a great selection of wide planks in many species in stock. You might also give Rick Hearne a call (888-814-0007) he's the owner and is agreat guy to deal with. I' sure he'll have a good laugh about cupping of wide planks. Good luck. Steve
I use full width boards whenever possible and don't worry a bit about it. As long as you attach the top in some way that it can move but remain flat, there won't be any problem. My rule is to always pick a board that came through the drying process and remained relatively flat; this means that it was inherently stable and is highly unlikely to warp once installed.
I broke that rule once, for a mahogany sideboard top. The lumber store had a nicely figured piece of 6/4 mahogany 27" wide that was cupped about 3/8" in the center. This was unusual since mahogany is very stable and remains flat. I bought it, and the old timer at the counter said it would crack, I knew right then it wouldn't because he was never right about anything. The sideboard, the last time I saw it, despite being placed near a forced hot air register, is just as flat as the day I finished it over 7 years ago and has not cracked.
On a side note, I did expect the sides to crack, because they were about 23" deep and restrained by the legs, but they haven't. I've made 3 other sideboards, and at least one of them has had the side crack, but this is just the nature of game, when building historically accurate reproductions.
Rob Millard
http://www.americanfederalperiod.com
DonStephan,Thanks for your points - could you expand on your point about "expansion and contraction across the width"? No pun intended. I belive my giant mortise and tenon design should do this. I'm going to post a link to my drawing in a second.frenchy,I was happy to hear someone else likes the 1-piece. Perhaps I have some old fashioned taste. Anyway it was good to hear about your success with the 22 and 48 inch planks. What species were those? I have received so many funny looks and scoffs at my 1-piece idea. Truthfully it just motivates me to prove them wrong - your feedback was validating so I appreciate it.David Ring,I enjoyed hearing about your experience with Wenge, Mahogony, Bubinga and Paduak. After a suggestion from this list last night, I went out and purchased a few wood encyclopedia type books to start learning more about each woods mechanical characteristics. I'll surely investigate bubinga before I think more about that awesome piece I found at the yard.miller,I would be very intersted in the thread you mentioned. I looked and looked for it last night but to no avail. Tried searching, and going through line by line a bunch of the different threads. Can you point me a little more in the right direction? Thanks a bunch. Also - I only dream of a 1-piece wenge that wide. I don't think they exist and have resigned to joining them if I go with that wood.philip,Can I get Pam Anderson to gun me down instead? Jane is kinda old for me. Like I said to miller, I don't anticipate finding a 1 piece wenge. Just like that species the best. I'll be sure to highly scrutinize whatever lumber I go with. I appreciate your notes on that topic. I'm not sure exactly how I will surface the top to flat. I have a nice beltsander that I could run over it but I'm worried about inconsistencies. Perhaps I'll just hand sand it for a weekend. Never used a scraper before but I'm reading a lot about them. Perhaps that is an option at some point in the process. I've saved off a jpg of the design I drew up in autocad. You can download it from my website here:
http://www.jimdoeden.com/2007/2/4/desk_web.jpg
Or if you have autocad:
http://www.jimdoeden.com/2007/2/4/desk.dwgIf I find a large enough 1-piece, I was going to make the legs out of the same material as the top. One heavy and bomb-shelter like bench/table/desk. Its definitely over-engineered to fit my taste for massive things. Anway; I was thinking of a giant mortise-tennon that I feel like I could do with my router. I was going to take 1/2" off of the end of the legs to create the male end. Then create a 1-1/2" mortise in the bottom of the table to create the female end. Thought of running a piece or two of 2x4 along the back to control the lateral movement and keep the side-to-side stress off the tenons. If you can take a look at the drawing I'd appreciate your feedback. I'm just in the early stages of designing this thing so if there are better ways I'll incorporate that.Shopdoc,Thanks for the reference to hearne. I'm in Atlanta, so it would be a weekend trip to go see their inventory. I will not rule that out though b/c I love PA during the seasonal changes.RMillard,I talked about my design in a reply to philip. See if you think it would allow for enough movement. I'm open to suggestions. And btw - congrats on your success with the mahog table. I'd love to see that.
gte33f
The 23 inch wide were white oak, the others were black walnut.
If you go thru the archieves of fine home building the 48 inch wide balck walnut was on a back cover.. (sorry my old mags are stored away and not accessable)
OK It took a little work, but I found it. Go to advanced search, and at the bottom you can enter in a message #. The first message posted was 34182.1 . There is a lot of discussion about wide boards.
gte333f
I looked but did not see any references to finishing in this thread...there may very well be but sometimes my eyes/mind betray me.
Whatever wood you decide to use, finish it on both faces and all the edges each time you apply a finish coat. If you sand the surface between coats, sand the underside between coats - no shortcuts. It will improve your chances of stability. Make sure the end grain is well sealed.
It you notice cracking/splitting, lock the split by installing butterflies (bow ties) from the underside. Do not fill any surface splits with veneers because they will function like a wedge over time and help the splitting to continue, Use coloured waxes to hide the cracks a bit. That way the wood will still be able to move it it needs to. JL
If you have a board 36" long, 12" wide, and 2" thick, it will not move very much in the length (36") or thickness (2") but may move on average 1/8" per foot in width (12"). Think of a frame and panel door, either ####cabinet door or a door in a house. Occasionally one will see a door that did not allow enough for seasonal movement of the panel. I've never seen seasonal movement push apart the two sides of the groove housing the panel (thickness movement), and I don't think I've ever seen seasonal movement push the top or bottom rail off the door (length movement). I keep a cabinet door I made from beech that during higher moisture pushes one style away from the top rail (width movement) to remind me that wood moves.Your table top initial design is 60" long and 34" wide. Assume you have a rectangular apron supporting the top, that is inset 4" all around, so it is 52" long and 26" wide. Your top likely will not move appreciably in length (60") but on average may move 1/8" per foot times 34/12 feet, or about 3/8" in width. If you secure this top to an apron and don't allow for expansion and contraction in width (and usually in length as good practice) the apron will be significantly stressed.
Since the legs and the top all have grain running in the same directions (I assume the grain runs up and down the legs and along the length of the top) they hould all change width together so that no particular stresses would be created that way. The whole desk would be changing width over the seasons perhaps 3/8's of an inch between winter and summer. Nothing will be restraining any twist in the top, but if you avoid boards that have shown any tendency to twist in the lumber yard you should be OK.
My computer would not open the drawings, or at least I could not figure out how to get the computer to open the drawings.
You can see the sideboard in the following link. It is the one in center. The photo was taken before I had a digital camera,so it is of pretty poor quality.
Rob Millard
http://americanfederalperiod.com/sideboards.htm
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