# Cracking chairs...



## Aurora North (Aug 13, 2015)

Hey guys,

So a buddy of mine and his partner just got their first job making a bunch of chairs for some restaurant along with matching tables. He and his partner fabricated the legs out of steel along with the spine. They decided to use white pine for the seats and the actual back rest (I would have done otherwise, but it's their show).

Anyway, I spoke to him today and he was distraught over the fact that all of their seats are cracking at the top of the radius. The shape is literally a rectangle that has a radius front edge. 12" wide to the peak of the radius and 14" (edit: long), made out of 4/4.

They have a 5 x 6" square plate that is welded to a pipe that goes down into a coupling so that it can swivel.

Any ideas as to why the seats would be cracking? Is the material just too soft/thin? He was saying they were cracking in the middle or close to it when they were just tapping them on the ground before even having them installed on the chair bases.

I'm worried for him that they're going to deliver something half ass and end up getting sued when these things start failing immediately or within a short time. Just trying to help him out. If you experienced guys have any insight I can forward to them I and they would seriously appreciate it.


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## Kevin (Aug 13, 2015)

Aurora North said:


> ... Anyway, I spoke to him today and he was distraught over the fact that all of their seats are cracking at the top of the radius. The shape is literally a rectangle that has a radius front edge. 12" wide to the peak of the radius and 14" wide, made out of 4/4.
> 
> They have a 5 x 6" square plate that is welded to a pipe that goes down into a coupling so that it can swivel.
> 
> Any ideas as to why the seats would be cracking?...



I am probably not the only man on this forum who cannot possibly picture what you described. I suck at it. If you post a picture I'm sure we could offer some good theories at least. Ask him to send you some from different angles then post them.

Reactions: Agree 6


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## Aurora North (Aug 13, 2015)

Will do. Just shot him a text. And sorry about the lack of pictures. Really appreciate the help though guys. I just don't want to see these guys fail on their first job. 

And I'm probably going to be going in with them on renting a shop so I have room to do my own stuff and they can kick me work here and there. But they seem to be more on the metalworking side and I'm completely on the woodworking side. When they said pine for restaurant chairs I jolted a bit considering the abuse that type of furniture receives. I did recommend that they might think about going with at least an ash or white oak. And the fact that these would be dead flat without any sort of scoop is kinda... eh... iffy. In my mind it's going to make for one uncomfortable chair after 15 minutes let alone 1 to 1 1/2 hours of dinner and conversation. But I'm no chair maker so perhaps I don't know what I'm talking about.


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## CWS (Aug 14, 2015)

I have a couple thoughts. One would be what % moisture in the seat blanks and two would be have they allowed for wood movement since they are on a metal frame.
Curt

Reactions: Agree 2


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## tocws2002 (Aug 14, 2015)

CWS said:


> I have a couple thoughts. One would be what % moisture in the seat blanks and two would be have they allowed for wood movement since they are on a metal frame.
> Curt



This was my thought also, based on the description of the chair it sounds like the wood was not fastened to allow for movement and/or the wood was higher in moisture content. 



Aurora North said:


> He was saying they were cracking in the middle or close to it when they were just tapping them on the ground before even having them installed on the chair bases



However, this statement has me wondering....if they were cracking before being installed, it really sounds like a moisture issue (or, if the seat is glued up, an issue with the glue and/or joining technique used).

Would also like to see a picture, as my opinion may change.

-jason


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## lonewolf (Aug 14, 2015)

with out really grasping the design i question the allowances for movement. but i can say 4/4 white pine is a bad choice.often when you see pine in furniture its really thick.


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## TimR (Aug 14, 2015)

Aurora North said:


> They have a 5 x 6" square plate that is welded to a pipe that goes down into a coupling so that it can swivel.
> ...He was saying they were cracking in the middle or close to it when they were just tapping them on the ground before even having them installed on the chair bases.


I'm sure we'll have a better idea when a pic or two is added, but in the absence of any butt loading, and cracking (couldn't make this kinda wordplay up) I'm wondering if they wood or metal screwed directly into the 4/4 without drilling pilot holes. "tapping" on ground before installed and cracking sounds like a lot of stress was in the wood, either drying stress or perhaps mechanical.
From the standpoint of allowing the wood to move, fastening to a steel plate does seem somewhat problematic for a 4/4 chunk of wood.
I'm wondering if having even one washer between the wood and plate, and not solid tightening down the screws would give the wood a chance to move during humidity changes...or if it's better to have a rigid connection??


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## Mike1950 (Aug 14, 2015)

I think all the above possible. Also screws could only have 3/4 bite in soft wood. I see a 300+ pounder on edge of stool a little bounce and screws stripping out. I think 4/4 is problematic.


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## Aurora North (Aug 14, 2015)

I'll get pics today. From what I understand they cut them out of solid wood. After I posted I called him and asked if he put a moisture meter on his stock. He didn't but said it was all kiln dried. So ideally in the 6-8% neighborhood. Not sure if that still to high. But you make a good point about the movement also. They were just going to screw them down to the plates and call it good which means nothing is going to allow for it to move.


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## Mike1950 (Aug 14, 2015)

Aurora North said:


> I'll get pics today. From what I understand they cut them out of solid wood. After I posted I called him and asked if he put a moisture meter on his stock. He didn't but said it was all kiln dried. So ideally in the 6-8% neighborhood. Not sure if that still to high. But you make a good point about the movement also. They were just going to screw them down to the plates and call it good which means nothing is going to allow for it to move.



Solid wood- 4/4 x 14" Yikes- they were doomed.


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## Aurora North (Aug 14, 2015)

Probably for the same reason I don't make rails that too wide right? They alway end up cracking.

Reactions: Agree 1


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## Aurora North (Aug 14, 2015)

Would doing a tongue and groove layup then cutting the shape help? I literally know nothing about chair civil ding myself so I apologize for the lame questions. I just feel like I have always heard they are difficult to build well.


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## Mike1950 (Aug 14, 2015)

Aurora North said:


> Would doing a tongue and groove layup then cutting the shape help? I literally know nothing about chair civil ding myself so I apologize for the lame questions. I just feel like I have always heard they are difficult to build well.



Only ? that is stupid is the ones you don't ask. I have not build chairs but know wood. A wide thin piece of wood usually will not be stable. Look at wood chairs- usually 2"-laminated pieces on seat or at least 2" solid. A chair takes a beating- stress in every direction.


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## Kevin (Aug 14, 2015)

Aurora North said:


> Would doing a tongue and groove layup then cutting the shape help? I literally know nothing about chair civil ding myself so I apologize for the lame questions. I just feel like I have always heard they are difficult to build well.



I literally know nothing about _civil ding_ either so I can't comment.

Reactions: Funny 5


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## lonewolf (Aug 14, 2015)

wasnt civil ding the prelude to civil war.

Reactions: Funny 4


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## Schroedc (Aug 14, 2015)

I'd think they'd need some sort of reinforcement across the grain on the bottom if what I'm seeing in my head is how they were built. My son loves wide pine scrap in my shop because it is so easy to split with the grain so he can play kung fu master......

Reactions: Funny 1


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## MikeMD (Aug 14, 2015)

My quick guess would be related to how the seats are affixed tot he chairs. If they are simply screwed or glued down (with no provisions for movement) this is a recipe for cracking. Think of it this way, the frame of the chair isn't going to expand and contract...it is a square frame. But the seat is a solid piece of wood that stretches over a foot. Wood can expand and contract up to 1/8 - 1/4" per foot across the grain (until it finds its settling point) depending on humidity and temperature. So, if the wood is trying to shrink, bu the frame won't...either the wood will split or the screws will snap. Sumthin's gotta give.

The solution, if the seats are just screwed down, is to make the oblong pilot holes that the screws are going through in the corner blocks. This will allow for the screws to move in the blocks with the movement of the wood (seats). 

Hope that helps. Moreover, I hope I'm accurate in my assumption of the chair's construction.

Reactions: Informative 1


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## Aurora North (Aug 14, 2015)

Damn phone auto correct and lag! Gave me a good laugh though after a painfully long day.


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## Aurora North (Aug 14, 2015)




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## Aurora North (Aug 14, 2015)

Alright guys, 

he shot me the pics today, but I had to wait to get home and upload; so here they are.

During lunch I was starting to research chair making and more specifically the seat construction. Fastest 30 minutes of a 12 1/2 hr day... So I didn't get very far, but I'll keep trying to dig up info while also taking into account everyone's insight. Which by the way, thank you all so much. 

Anyway, as you can see that plate allows for no movement at all. He gave me a call today and told me they returned the pine and switched to poplar. Again, wouldn't be my choice as a seat material considering wear and tear, but it's their call and their budget. When I saw these I was surprised at the screw... I honestly thought it was a smooth bore swivel of some sort.


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## Brink (Aug 14, 2015)

If someone sat and spun their seat, it could unscrew and fall out?

Reactions: +Karma 1


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## Mike1950 (Aug 14, 2015)

Brink said:


> If someone sat and spun their seat, it could unscrew and fall out?



hell drunks would never do that!!!

Reactions: Funny 1


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## DKMD (Aug 14, 2015)

Looks like a fair bit of overhang between the front edge of the plate and the front of the seat... Especially given the grain is running side to side in the seat. Turning the seats 90 degrees( to make the grain run front to back), increasing the thickness to 6/4, and making the holes in the plate oversized would probably go a long way toward fixing the cracking. 

There are a lot of other folks here who know more about wood and chairs, so I'm interested to read their thoughts

Reactions: Agree 2


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## Sprung (Aug 14, 2015)

Keller must've been reading my mind - my thoughts exactly. I'd switch to 6/4 material, change grain direction, make a larger plate, and elongate the holes in the plate to allow expansion and contraction of the wood with seasonal changes. I'd probably also consider changing to oak or ash over pine or poplar. But, I'm also no expert on chairs either.


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## barry richardson (Aug 14, 2015)

White pine is a very stable wood, doubt if it is from wood movement so soon, unless the wood was not fully dry. I saw a segment of Roy Underhill where he said white pine was usually what was used for windsor seats and other chairs back in the day because of stability and easy carving, regardless of what the rest of the chair was made of. Probably just too thin and the wrong orientation choice like Doc said... Don't think poplar will do any better, unless he follows the Doctors instructions...


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## Brink (Aug 15, 2015)

Mike1950 said:


> hell drunks would never do that!!!



Wasn't thinking drunks. Saw a NY license plate from the other side of the river. And I'm sure we all know how those people are. @NYWoodturner

Reactions: Funny 1


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## ripjack13 (Aug 15, 2015)

depending on the budget, The easiest way to stop them cracking is to double up the seat. Alternating the grain and glue em up....


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## Kevin (Aug 15, 2015)

I'm seeing more than one type of base for the chairs in the photos. I don't believe there is an easy fix for that though. Looks like a scrap and redesign to me.

Reactions: Agree 1


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## Kevin (Aug 15, 2015)

I just took another look. The metal fabrication makes no sense for a production contract and the work is shoddy. I am actually a better fabricator and that ain't saying much. Not only is it labor and material intensive, the naked steel will not be easy to maintain. I think this job was between two people who are not good businessmen -- neither one. The restaurant owner is a cheapskate and your buddy is willing to try and satisfy a cheapskate. Never gonna work. JMO.

Reactions: Agree 1


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## Aurora North (Aug 16, 2015)

Supposedly it's for a burger joint named TNT burgers and grill that wanted a rustic look. So no alcohol or presumably hour+ stays.

The last picture isn't a chair. That's a table top sitting on a random stand that was in the shop.

I told him he needed to weld a stop nut on the bottom of the screw so people can't turn it past a certain height (thinking kids playing and spinning it loose).

And following sprung's advise to make larger holes so that the seat has room to expand and contract.

As far as their business sense I'm leaving that on them and I'm staying out of that. I wouldn't be satisfied with this product as a producer. And having already tried to tell them things to change to make the product better ended at "it'll cost too much and go over budget". (They already made a bunch in this design)

They didn't want to enlarge the support plate either because it would cost too much... Pretty frustrating. 

As far as maintaining the steel I recommended sealing it with a matte finish to keep the patina but prevent rusting. Got the same response to every recommendation that required more material/time.

Sigh... Only so much you can do I guess. Hope it doesn't come back in the form of a lawsuit if something fails and someone gets hurt. But that's on them. 

Thank you to all of you guys for weighing in with advise. I'm in agreement with you Kevin. This design should have been a prototype and then improved/ redesigned to something acceptable before production even started on the rest. I'm not sure they even went around and looked at other companies work to get an idea in construction...

Reactions: Like 1


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## lonewolf (Aug 16, 2015)

i have to agree with kevin. the design of these chairs is bad. chair building (especially commercial use) shouldnt just totally disregard tried and tested methods that were over a thousand of years in developement. somebody has jumped in way over their head.

Reactions: Agree 1


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## gman2431 (Aug 16, 2015)

If someone doesn't get hurt it'll be a miracle. Especially an overweight person.

Reactions: Agree 1


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## Aurora North (Aug 16, 2015)

I'm worried for them about this especially. I test sat in the one in the shop and with very little pressure on my heels I could get the chair onto the two back legs in a tipping fashion. I weigh 140... Can only imagine what it'll be like if someone who weighs 200-300lbs sits on these. If the wood even holds it'll be a miracle. If the back support doesn't bend it'll be a miracle. Let alone mentioning if the whole thing doesn't go over backward. I brought that up right away knowing they weren't going to change it. That's about when I just started biting my tongue.


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## Kevin (Aug 16, 2015)

Aurora North said:


> I'm worried for them about this especially. I test sat in the one in the shop and with very little pressure on my heels I could get the chair onto the two back legs in a tipping fashion. I weigh 140... Can only imagine what it'll be like if someone who weighs 200-300lbs sits on these. If the wood even holds it'll be a miracle. If the back support doesn't bend it'll be a miracle. Let alone mentioning if the whole thing doesn't go over backward. I brought that up right away knowing they weren't going to change it. That's about when I just started biting my tongue.



If I were you I would distance myself from it. I know you're trying to help them but you have given them enough advice to become part of any lawsuit filed once the plantiff's attorney's start discovery. You might not be found liable but you'll have to prove they didn't use any of your advice and you'll have to hire an attorney to defend yourself. If this sounds far-fetched then you haven't been exposed to the US Justus system yet . . . . .

Reactions: Agree 1


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## Aurora North (Aug 16, 2015)

Yeah man,

I'm pretty much done. Made the suggestions I thought would help. I'm not going to recommend anything in terms of design. If they deliver these and it all works out then they dodged an rpg. If not... Well that's their mess and just means I'll have to move my machines out of the shop.


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## Kevin (Aug 16, 2015)

I don't see why you'd have to move out of the shop. Just don't be involved in that project. I wouldn't give them a notice about it or anything, just whenever they ask for advice say you're not real sure and have to think about it. They'll get the hint eventually.


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## Brink (Aug 16, 2015)

Hmmm, so, let's say I visited this establishment,( and I think it's near me) and a horrible accident occurred, I just need to contact one of those 1-800 lawyer places and everyone involved could be paying me? Even the people who gave advice?

Wouldn't it just be easier to send me my go away $?

Reactions: Funny 1


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## Aurora North (Aug 16, 2015)

Sorry, didn't mean I was packing up and getting out. Just down the road if it bites them and they can no longer rent the shop we are moving into. Nothing has happened yet so I'm still planning to get set up to work on my own stuff.

Edit: brink you might actually be close by. Tell you what, I'll start sending you the new turning rage... Cast/ stabilized peanut shells. Ultra rare, highly figured, peanut shells. 1 per month due to rarity/ high demand.

Reactions: Funny 1


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## Brink (Aug 16, 2015)

I've never turned a piece of wood


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## DKMD (Aug 16, 2015)

On the bright side, most restaurants close within a year of opening. On a down note, those chairs aren't likely to make it that far.

Reactions: Funny 3


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## Brink (Aug 16, 2015)

Hmm, can I see a bunch of TCTSNH threads?

Reactions: Funny 3


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