How did George Nakashima do it?
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Crazyraceguy
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Years ago, in the old shop, I made a "proof" gauge. This was to show one of the guys I worked with, that expansion/contraction was real. It was a simple piece of Red Oak, that I glued up to be 12" wide, but only 2" long. Then I glued and pinned one end of it to another piece that was 2" wide and 12" long. Then I trimmed the assembly to be perfectly flush on the un-connected end. This gives you are cross-grain sample.
At that point, we wait. Depending on the time of year and weather conditions, something will happen.
This varies, of course, by species, and the way the "wide" piece was cut from the tree. Some move more than others.
You could go crazy and speed things along, by spraying some water on it or even dunking it to be really in a hurry.
At that point, we wait. Depending on the time of year and weather conditions, something will happen.
This varies, of course, by species, and the way the "wide" piece was cut from the tree. Some move more than others.
You could go crazy and speed things along, by spraying some water on it or even dunking it to be really in a hurry.
smorgasbord
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smorgasbord
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jeffinsgf said:
Yeah, growing up with Nakashima furniture certainly was one of the major reasons I became a (hobbyist) woodworker.
[member=77266]smorgasbord[/member] Wow. That's stunning. And your dining room ain't too shabby either!
One of my friends kept telling me that she grew up around Nakashima's furniture (her family was quite well-to-do) but since I was unfamiliar, it didn't really register other than "cool." Then after seeing this thread I looked up his work and it's remarkable. New Hope is only a couple hours from me so I'd like to have a visit when they open up tours again later this year.
One of my friends kept telling me that she grew up around Nakashima's furniture (her family was quite well-to-do) but since I was unfamiliar, it didn't really register other than "cool." Then after seeing this thread I looked up his work and it's remarkable. New Hope is only a couple hours from me so I'd like to have a visit when they open up tours again later this year.
smorgasbord
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onocoffee said:
I just checked - the table cost $600 in 1973.
As I've mentioned before, wood movement depends on many things.
But I wouldn't overanalyze how did Nakashima do it. He just screwed it together hoping for the best. I doubt he gave it a second thought. Luckily it didn't split. And if it did split everyone would be raving how that crack gives the piece a character and that was intentional and genius
.
Great artists aren't always meticulous engineers.
But I wouldn't overanalyze how did Nakashima do it. He just screwed it together hoping for the best. I doubt he gave it a second thought. Luckily it didn't split. And if it did split everyone would be raving how that crack gives the piece a character and that was intentional and genius
.Great artists aren't always meticulous engineers.
This whole discussion is a perfect example in the wood world of having the principles on one hand and on the other the practical side. I don't see any reason why both aren't true from a first principles perspective and yet the conditions and particular nature of each piece is going to set in motion slightly different outcomes etc. Yes, wood movement happens but does it happen uniformly, well, no not exactly.
In this case, I really don't see why the gap between the two boards wouldn't be sufficient and the screws on the underside really don't conflict with each of those boards swelling and shrinking over time. And like someone else I think mentioned the screws in this case would only have to allow for very little movement if kept in a mostly conditioned space and even in a less conditioned environment I still would be surprised to see this design not handling the movement well. There's really nothing about the structure of the table where the top could directly bust the understructure. Or apply much stress as the top is free to expand and contract. In fact, those two boards doing there thing slowly over time would put very little stress on how those pieces on the underside are supporting the top and attaching to it.
Not over thinking something is often the hardest problem to solve!
In this case, I really don't see why the gap between the two boards wouldn't be sufficient and the screws on the underside really don't conflict with each of those boards swelling and shrinking over time. And like someone else I think mentioned the screws in this case would only have to allow for very little movement if kept in a mostly conditioned space and even in a less conditioned environment I still would be surprised to see this design not handling the movement well. There's really nothing about the structure of the table where the top could directly bust the understructure. Or apply much stress as the top is free to expand and contract. In fact, those two boards doing there thing slowly over time would put very little stress on how those pieces on the underside are supporting the top and attaching to it.
Not over thinking something is often the hardest problem to solve!
smorgasbord
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mcooley said:
Look at the photos again:
• There are screws going through the cross-member into the two top pieces just a couple inches from the gap. That effectively fixed the gap, except for as much as 4" of wood might move.
• There are 3 more screws in each board, such that the outside ones are 14.5" from the inside ones.
This 14.5" of cross-grain construction in each top piece is what's in contention here. Typically one would expect between ⅛" and ¼" of width change across 12". If that's accommodated by the screws, then after 50 years one would expect those screws to be loose, and there's absolutely no indication of that.
mcooley said:
This is true as Svar pointed out: "wood movement depends on many things.."
The only problem is that Nakashima or any maker wouldn't know under what humidity conditions their furniture pieces were going to be subject to after their sales. So the only way to prevent any potential wood movement concerns was to assume that they would happen and plan for them during the design/construction phase. Nakashima, as shown in the extract, was very clear about that.
Of course, a less knowledgeable woodworker might not be aware of the potential fault, or someone who cuts corners might fail to heed his advice.
smorgasbord
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So I ran across a wood movement calculator on Katz-Moses's site:https://kmtools.com/pages/wood-movement-calculator
The problem is that assumes your furniture will reside in where you build it. That may be fine for some, but young families might move, I've given some baby furniture items to family in other parts of the country. And certainly a professional would want his/her furniture to stand up no matter where it goes.
When I ran the numbers for 30" wide flatsawn cherry in NorCal, I get just under 5/32" of total movement seasonally. Less for quartersawn. And even less for indoor use with smaller humidity extremes.
Now, if my piece ends up in Bishop, CA, it could move a total of 7/16".
Or in Juneau Alaska, ⅜"
But if the piece might live in Juneau for a couple years and then end up in Yuma, the calculator won't help - I need to go to the formula and table of numbers, which Katz-Moses provides here:https://kmtools.com/blogs/news/planning-for-wood-movement
Co-efficient for Cherry (flatsawn) is 0.00248
Humidity max for Juneau is 18.1
Humidity min for Bishop is 3.6
The formula then is:
30 * 0.00248 * (18.1-3.6) = 1.08" or 1 & 5/64" !!!!
But, as the site says, these are outdoor humidity changes. I suspect indoor humidity varies less, but will vary based on location due to how much heat is needed in winter, etc. So, it's still a puzzle to me.
On the good side, however, modern wood finishes will slow down the exchange of moisture from the piece to/from the atmosphere, so for single locations the humidity extremes in the wood itself will be dampened/reduced. That's great if your piece lives where you build it, but if you move, watch out?
The problem is that assumes your furniture will reside in where you build it. That may be fine for some, but young families might move, I've given some baby furniture items to family in other parts of the country. And certainly a professional would want his/her furniture to stand up no matter where it goes.
When I ran the numbers for 30" wide flatsawn cherry in NorCal, I get just under 5/32" of total movement seasonally. Less for quartersawn. And even less for indoor use with smaller humidity extremes.
Now, if my piece ends up in Bishop, CA, it could move a total of 7/16".
Or in Juneau Alaska, ⅜"
But if the piece might live in Juneau for a couple years and then end up in Yuma, the calculator won't help - I need to go to the formula and table of numbers, which Katz-Moses provides here:https://kmtools.com/blogs/news/planning-for-wood-movement
Co-efficient for Cherry (flatsawn) is 0.00248
Humidity max for Juneau is 18.1
Humidity min for Bishop is 3.6
The formula then is:
30 * 0.00248 * (18.1-3.6) = 1.08" or 1 & 5/64" !!!!
But, as the site says, these are outdoor humidity changes. I suspect indoor humidity varies less, but will vary based on location due to how much heat is needed in winter, etc. So, it's still a puzzle to me.
On the good side, however, modern wood finishes will slow down the exchange of moisture from the piece to/from the atmosphere, so for single locations the humidity extremes in the wood itself will be dampened/reduced. That's great if your piece lives where you build it, but if you move, watch out?
