Author Topic: Domino Ladder  (Read 18033 times)

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Offline Timtool

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Re: Domino Ladder
« Reply #30 on: May 04, 2011, 01:54 AM »
come on guys, we have all assembled laquered mdf ikea kid beds that hold together with less than 10 8mm dowels and screws.
so i would say it depends on the material you use, and the thickness.
i think two domino's per side would be verry hard (impossible?) to break for kids, it's the steps themselves that could fail faster, if you follow the 1/3 rule, then with a 10mm domino, you need a step of 30mm thick for maximum resistance. if the material is of same hardness as the beech domino's
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Offline Eli

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Re: Domino Ladder
« Reply #31 on: May 04, 2011, 06:20 AM »
I have three kids. They have a bunk bed. My kids are your kid's ages, a bit older.
Their ladder is not as strong as what you are talking about building. The bunk ladder at our house shows little sign of wear after two years.
The boys take turns on who sleeps up top. Both climb it.
I think the allthread to hold it together is a great idea. I don't think it will break. I'm a rigger. I climb ladders for a living.
Of course no one here is accepting liability by advising him to build his own ladder, but seriously.
In general, things don't explosively fail even under my six year old, who is like a superball stuffed with dynamite.
I would say it might be a good idea to secure it to the bed by through bolting it. Use Nylock nuts and washers with your bolts.
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Offline chris mann

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Re: Domino Ladder
« Reply #32 on: May 04, 2011, 09:45 AM »
I've built similar things, the domino is plenty strong.  Especially when you compare it to any bunk bed ladder you'd get from a store.
If you want some more assurance, domino everything together, making the domino depth 28mm instead of 25mm.  Dry assemble and mark the treads on the stringer and then trench the stringer 5mm.  If your stringer is less than 28mm, you could make your own dominos and then wedge them in place as well, but I don't think it's necessary.

Offline fdengel

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Re: Domino Ladder
« Reply #33 on: May 04, 2011, 11:01 AM »
Bottom line, I don't think I'd trust a domino for this if it is on its own.  At minimum, use dominos plus something else as a backup -- pocket hole screws come to mind, or screws through the side into the rails...

Offline William Herrold

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Re: Domino Ladder
« Reply #34 on: May 04, 2011, 11:35 AM »
I just Finished a set of chairs- 268 dominos and 64, 8x35x40mm actual tenons. Tell you what I'll do- I'll mock up 2 ladder rungs in tight-grained D.Fir, and glue in 3- 10x50 doms on each side of each rung with PVA glue, let it dry for one week, then load it with my porta-power. Said unit will produce a 22 metric ton load on a diameter of 55mm, I can measure the BAR- pressure on my meter, up to 160, that will enable me to give a close point of failure in kilograms. For the sake of accuracy, as no one with 2 legs climbs a ladder stepping in the middle of a rung, apply the load about 1 decimeter from the joint.
-I welcome anyone with pointers on how to make the experiment more viable to speak up, as I'm no engineer.
 
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Offline Jesse Cloud

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Re: Domino Ladder
« Reply #35 on: May 04, 2011, 11:59 AM »
I just Finished a set of chairs- 268 dominos and 64, 8x35x40mm actual tenons. Tell you what I'll do- I'll mock up 2 ladder rungs in tight-grained D.Fir, and glue in 3- 10x50 doms on each side of each rung with PVA glue, let it dry for one week, then load it with my porta-power. Said unit will produce a 22 metric ton load on a diameter of 55mm, I can measure the BAR- pressure on my meter, up to 160, that will enable me to give a close point of failure in kilograms. For the sake of accuracy, as no one with 2 legs climbs a ladder stepping in the middle of a rung, apply the load about 1 decimeter from the joint.
-I welcome anyone with pointers on how to make the experiment more viable to speak up, as I'm no engineer.
 

What a great idea!  Thanks for doing that.  If the Dominoes are glued to long grain in both the legs and the rungs, I predict the failure will be either the leg or rung breaking or the Dominoes pulling out of the legs or rungs.  I don't think the failure will be sudden.  Can you do a video?

Offline Tim Raleigh

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Re: Domino Ladder
« Reply #36 on: May 04, 2011, 12:40 PM »
Kids are 5, 2, and one due tomorrow.  45 pounds on the top end. 

Remember that some overgrown children (adults) may want to use this as well.
Seriously if you or your wife (grandparents, babysitters) has to go up that ladder then you might also consider that in your calculations.
Tim

Offline maxpower10

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Re: Domino Ladder
« Reply #37 on: May 04, 2011, 02:44 PM »
I just Finished a set of chairs- 268 dominos and 64, 8x35x40mm actual tenons. Tell you what I'll do- I'll mock up 2 ladder rungs in tight-grained D.Fir, and glue in 3- 10x50 doms on each side of each rung with PVA glue, let it dry for one week, then load it with my porta-power. Said unit will produce a 22 metric ton load on a diameter of 55mm, I can measure the BAR- pressure on my meter, up to 160, that will enable me to give a close point of failure in kilograms. For the sake of accuracy, as no one with 2 legs climbs a ladder stepping in the middle of a rung, apply the load about 1 decimeter from the joint.
-I welcome anyone with pointers on how to make the experiment more viable to speak up, as I'm no engineer.
 


Great idea!  I'd love to see that.  A video of it would be ideal! Thanks!
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Offline woodguy7

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Re: Domino Ladder
« Reply #38 on: May 04, 2011, 05:28 PM »
Maxpower, is the one that was due here yet ?  [smile]
If its made of wood, i can make it smaller.
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Offline maxpower10

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Re: Domino Ladder
« Reply #39 on: May 04, 2011, 05:41 PM »
Maxpower, is the one that was due here yet ?  [smile]

No, due today.  No action yet.  The doctor will induce a week from tomorrow if the stubborn little guy doesn't want to show up before that.  My wife says he's waiting for me to finish his crib.  Just waiting on hardware.
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Offline woodguy7

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Re: Domino Ladder
« Reply #40 on: May 04, 2011, 05:44 PM »
Go get an Indian takeaway, it worked for us with our second boy  [thumbs up]

Only problem is she was sick in the hospital  [doh]  Not so keen on curries after that.

All the best anyway  [big grin]
If its made of wood, i can make it smaller.
Shirt size medium
p.s- ive started reading these too

Offline Eli

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Re: Domino Ladder
« Reply #41 on: May 05, 2011, 05:03 AM »
I want to see the load test. My money is on the rail failing in the middle, before dominos fail.
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Offline Wonderwino

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Re: Domino Ladder
« Reply #42 on: May 05, 2011, 08:05 AM »
A totally non-Festool solution would be to emulate the ladders of the Pueblo Indians of the American Southwest.  They simply lashed rungs to notched rails with rawhide, which tightened as it dried and shrank.  Some of the ladders still in use are hundreds of years old. 
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Offline Michael Kellough

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Re: Domino Ladder
« Reply #43 on: May 05, 2011, 09:32 AM »
A totally non-Festool solution would be to emulate the ladders of the Pueblo Indians of the American Southwest.  They simply lashed rungs to notched rails with rawhide, which tightened as it dried and shrank.  Some of the ladders still in use are hundreds of years old. 

Kids would dig that too!

Offline online421

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Re: Domino Ladder
« Reply #44 on: July 24, 2017, 10:56 PM »
For the record if anyone is reading this, Australia and New Zealand has a bunk bed safety standard. In the standard there are various safety requirement, there is static load requirement and dynamic impact load requirement on the ladder, unfortunately you have to buy the standards to get a soft copy, it cost about $120 USD after tax.

Without going into too much detail,

For static load requirement you are to test the ladder by putting an object of 1500N at 100mm interval of the tread for 30 seconds at each interval

For dynamic load, your ladder should be subjected to an impact load of 15kg, located at 400m from the tread and impact the tread at 150mm distance for 10 impacts, the 15kg object is tied to a rod that is 1000mm from the centre of its pivot point. the tread is 1400mm from the pivot point.

If you require further info about relevant safety requirement in this safety standard, send me a PM.
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Offline NL-mikkla

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Re: Domino Ladder
« Reply #45 on: July 25, 2017, 08:30 AM »
Come on guys - how many bunkbed ladders have been built and used for years and years with only 2x4's + 10D nails or 3" drywall screws?

Surely the shear strength of (3) 10mm Dominos would exceed those methods and be plenty strong for 30-100lb children to use?

More Dominos may not make for a stronger joint, but they'll surely increase the shear load for each ladder rung.

I've climbed up lesser structures, and I'm close to 200lbs.

JT

My thought exactly, I'd go for the domino way easily.

Offline Harry1561

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Re: Domino Ladder
« Reply #46 on: July 25, 2017, 04:45 PM »
For the record if anyone is reading this, Australia and New Zealand has a bunk bed safety standard. In the standard there are various safety requirement, there is static load requirement and dynamic impact load requirement on the ladder, unfortunately you have to buy the standards to get a soft copy, it cost about $120 USD after tax.

Without going into too much detail,

For static load requirement you are to test the ladder by putting an object of 1500N at 100mm interval of the tread for 30 seconds at each interval

For dynamic load, your ladder should be subjected to an impact load of 15kg, located at 400m from the tread and impact the tread at 150mm distance for 10 impacts, the 15kg object is tied to a rod that is 1000mm from the centre of its pivot point. the tread is 1400mm from the pivot point.

If you require further info about relevant safety requirement in this safety standard, send me a PM.
As beautiful a it is to live in, Australia is so over regulated and full of red tape. The next generation won't know how to think for themselves. ..That's my rant for the day , now for some work  😊

Offline HarveyWildes

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Re: Domino Ladder
« Reply #47 on: July 25, 2017, 07:26 PM »
There is no way that a 10mm domino is going to shear under any reasonable load, but the wood could split around it.  If you want to build a really strong ladder put a 3/8-1/2 dado at each step into the supports, then use the dominos and glue and clamp it together.  You can run the dominos through from the outside if you want a decorative effect or domino the supports then cut the dado after the fact.  You may have to cut down the dominos if you go that route, if you do then glue the dominos into the steps then cut to length with a miter saw.

More or less what I did with the last bunk beds I made, but with sliding dovetails on the top and bottom steps.