Domino Ladder

[maxpower10]

OK, I'll ask a stupid question?  How old are your kids?  How much do they weigh?  How long do you think that they will be using the top bunk?  Is your ladder going to be totally vertical or at a slight incline?  All these types of issues come into play.

Not be sarcastic - really want to know.

Peter

Kids are 5, 2, and one due tomorrow.  45 pounds on the top end.  Just needs to last until I build a bigger home.  Definitely would be at a slight angle.  I would expect it to carry all of 200 pounds up the ladder to feel safe to have my kids and others climbing on it.  Building a test one and doing to destructive testing would be a great and fun idea.  I may just do that and see what it takes to make it fail.

 

[peter halle]

I'll have special thoughts for you and yours over the next few days!  Good Luck!  You seem to be doing what I I was going to offer to do once I got more details.  I can't wait to hear the results on both sides.

Peter

 

[mouppe]

I would build it like this. My kids (2 and 4) are always climbing up this bookshelf and it is plenty strong enough. It's also really easy to put together.

 

[woodguy7]

OK, my turn.

I would not take the chance if it is for my kids or anyones kids.  Its ok to say if they come slack then do something about it but i think if it fails it will fail suddenly & quickly i,e - they will just snap.  I think enough people on this thread think it would be a bad idea but if you want to take that chance then its up to you.  I have made a small ladder for a library & i housed each step in on sliding dovetails.  Really not difficult to do & very secure.

If you decide to try it then i wish you all the best.

Woodguy.

 

[jmbfestool]

How wide would you be making the ladders that makes a difference I think having them wider apart creates more of a bending force if they was just to use one leg in the centre  a narrow set will give a more direct downwards force on the dominos.   NO?  Im just making up stuff lol!

Them oak stairs I fitted not long ago which I posted on here! Well the client had some crappy made up softwood stairs a builder made temp they had them stairs for 10 years!  10 years!  [eek] [scared] [scared]   Well the builder just butted up the treads of 6x2 to the 8x2 strings  he just nailed 2 nails on each side!  Well they held lol I know I would not of risked it.   Any way for a bunk bead I think Dominos should be fine seen as two nails with proper adult weight held!  

I properly wouldn't do it my self! umm.... I properly make one and test it dry with no glue if it held me with me bouncing on it with no glue it will  definitely hold with glue

When I was a kid  (I still am! So I know!) I often only used the second tread only on my bunk bed! I would kinda jump up to the second tread with my right leg only and with some force kinda throw my self up and over in one go and getting out of the bunk bed I would always just jump of never used the ladders!   So all you need to do is house the second tread and make sure you kids do the same lol!

JMB

 

[peter halle]

How wide would you be making the ladders that makes a difference I think having them wider apart creates more of a bending force if they was just to use one leg in the centre  a narrow set will give a more direct downwards force on the dominos.   NO?  Im just making up stuff lol!

Them oak stairs I fitted not long ago which I posted on here! Well the client had some crappy made up softwood stairs a builder made temp they had them stairs for 10 years!  10 years!  [eek] [scared] [scared]   Well the builder just butted up the treads of 6x2 to the 8x2 strings  he just nails 2 nails on each side!  Well they held lol I know I would not of risked it.   Any way for a bunk bead I think Dominos should be fine!   

I properly wouldn't do it my self! umm.... I properly make one and test it dry with no glue if it held me with me bouncing on it with no glue it will  definitely hold with glue

When I was a kid  (I still am! So I know!) I often only used the second tread only on my bunk bed! I would kinda jump up to the second tread with my right leg only and with some force kinda throw my self up and over in one go and getting out of the bunk bed I would always just jump of never used the ladders!   So all you need to do is house the second tread and make sure you kids do the same lol!

JMB

This explains so much!  [poke]

Peter

 

[woodguy7]

LOL

 

[jmbfestool]

[embarassed]

 

[peter halle]

[embarassed]

Yep.

 

[Kevin Stricker]

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.

 

[Timtool]

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

 

[Eli]

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.

 

[chris mann]

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.

 

[fdengel]

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...

 

[spikfot]

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.

 

[Jesse Cloud]

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?

 

[tiralie]

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

 

[maxpower10]

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!

 

[woodguy7]

Maxpower, is the one that was due here yet ?  [smile]

 

[maxpower10]

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.