oak staircase made with festool domino
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PaulMarcel
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fritter63 said:
Actually no matter where you are in the US you'd likely have to put a Prop 65 warning on it (and everything else)
I'm studying to be a structual engineer...
I wanted to test the domino's strenght. So I made a bench like this out of solid birch:
(This one was not made by yourstruly)
I only used 3 5mm dominos/joint, glueing only the domino and not the whole joint.
I gave the bench to a friend and didnt tell that it might not be structually sound so he wouldent be afraid to use it. And still a year later the joints have held up great.
Thought it might be a good prank but the damn dominos are too tough [mad]
The shear resistance in dense 800kg/m3 beech is really high, comparing to other woods(even oak,mahogny...). I guess festool uses proper beech for the dominos...
I wanted to test the domino's strenght. So I made a bench like this out of solid birch:
(This one was not made by yourstruly)
I only used 3 5mm dominos/joint, glueing only the domino and not the whole joint.
I gave the bench to a friend and didnt tell that it might not be structually sound so he wouldent be afraid to use it. And still a year later the joints have held up great.
Thought it might be a good prank but the damn dominos are too tough [mad]
The shear resistance in dense 800kg/m3 beech is really high, comparing to other woods(even oak,mahogny...). I guess festool uses proper beech for the dominos...
...The domino's are the most important pieces in that construction method. They're the ones taking most of the forces. The glue isnt doing much at all. When weight is applied on the bench the forces will try to shear the dominos. The dominos transfer the most forces to the "leg" components.
Many domino joints i've seen on these forums have been overkill, in the sense of the forces an array of dominos will have to endure in the application.
One thing an engineer has to avoid is overkill. For example, here in Finland we dont design our houses to withstand hurricanes or earthquakes because a situation where a house here has to withstand that kind of forces is so rare. The same logic can be applied to these stairs, I dont suppose they're gonna try to park their humvee in the stairs.
By the way if you want more strenght for the dominos place them vertically towards the forces.
That way they should have about 1,5 times more strenght towards the force.
Sorry for my late night ramble, its 3 am here.
Many domino joints i've seen on these forums have been overkill, in the sense of the forces an array of dominos will have to endure in the application.
One thing an engineer has to avoid is overkill. For example, here in Finland we dont design our houses to withstand hurricanes or earthquakes because a situation where a house here has to withstand that kind of forces is so rare. The same logic can be applied to these stairs, I dont suppose they're gonna try to park their humvee in the stairs.
By the way if you want more strenght for the dominos place them vertically towards the forces.
Sorry for my late night ramble, its 3 am here.
John Stevens
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- 815
j123j said:
Well, I dropped out of the engineering curriculum after six weeks but I've spent many years dealing with the process of determining liability and damages (bodily injury and property) arising from construction failures. :
I think the reason engineers avoid overkill is out of consideration of material and labor costs. But on the other hand, they try to avoid the cost of failure (including liability) by designing in a "margin of safety" that accounts, as far as one reasonably can, for peak usage, inappropriate usage, emergency usage and those "things we don't know we don't know" (as Donald Rumsfeld put it). The OP thinks he's struck the right balance between minimizing construction costs and minimizing the risk of failure, and let's all hope he has.
Regards,
John
pierreblonde
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Nice job but !!!!!!
I too am with woodguy and the others , the Domino is a great tool for the right job but i can't see or ever dream of using it for this instead of housing the string ?? its been done that way for hundreds of year. Does that mean its old fashioned or its just the best way to do it !! it must have taken longer to do as well
sorry don"t mean to offend
I too am with woodguy and the others , the Domino is a great tool for the right job but i can't see or ever dream of using it for this instead of housing the string ?? its been done that way for hundreds of year. Does that mean its old fashioned or its just the best way to do it !! it must have taken longer to do as well
sorry don"t mean to offend
Captainwrinkles
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- Jan 16, 2010
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No Criticism here.
Im curious. How are the stairs holding up? Any creaking/noise from movement?
Benn
Im curious. How are the stairs holding up? Any creaking/noise from movement?
Benn
Beautiful design and execution. Was this your design or an architect ?
After thinking about the structural strength of the design I don't any problems. The triangular placement of the domino tenon front and back makes this a solid structure. The shear strength of one 8-50 domino is rated at around 600 pound in one articles I read. So your 12 tenons, 10-50 I suspect, should place you in the over engineered category.
Thank you for sharing.
Bruce
After thinking about the structural strength of the design I don't any problems. The triangular placement of the domino tenon front and back makes this a solid structure. The shear strength of one 8-50 domino is rated at around 600 pound in one articles I read. So your 12 tenons, 10-50 I suspect, should place you in the over engineered category.
Thank you for sharing.
Bruce
