iDRY Vacuum Kilns

Sponsors:

Loft bed design and build

Started by Crusarius, December 17, 2021, 01:26:15 PM

Previous topic - Next topic

0 Members and 1 Guest are viewing this topic.

Crusarius

So this is my first real wood working project and the most intricate / detailed I have ever attempted. Most of my previous projects have been cheap 1x pine that turned into DVD cabinets and stuff. the most detailed joinery I used was a blind dado.

This loft Bed is made using Hickory for the cross members and Walnut for the legs. I I harvested, sawed, and air dried all of the wood myself. Pretty kool victory to be able to say you can do all that.

Ok, now on to the project.

I wanted to build a 6' tall loft bed for my oldest son. This way he will have plenty of room under it to make his room a bigger mess :) I wanted to avoid using mechanical fasteners but I still want to be able to break it down to move.

For the top corners I chose what I think is called a castle joint. And the other corners was a modified version of it.

Here is the full project as it sits now (see below)


 
Detail is kind of hard to see with all the background noise. What is not shown in the picture is another long cross member between the two that are there. I forgot to put it in during assembly.

So I was all excited with how tight all of my joints ended up. I was thinking this bed is going to be nice and stout and not rack all over the place when he is flipping and flopping trying to get comfortable.

Unfortunately I was wrong :( During assembly I broke of two of the hook tabs I used to lock it all together. I think that is where all my rigidity went in the long direction.

Here are the two pieces I used to make the corner connections. The reason the one hook is shorter than the other is because of the pocket they are inserted into.


 


 

On the bench, the single bracket locked together was really tight and had very little movement. Unfortunately, I guess having 6' tall legs kinda amplifies the forces acting on the joints.

So now I am rethinking my "no mechanical fasteners" and thinking about using furniture bolts to lock the corners together. Does anybody have any ideas for how I can fix this without redoing everything?

This is what I am thinking. Not sure if its the right way or not. The top picture is my current detail. The bottom picture shows the addition of the furniture bolts. The hook would have to be removed and then used as a stop block with the furniture bolts.




Quick link to gallery for more pictures

kantuckid

For starters-Anything I say is intended to be helpful not to criticize! 
When I looked at the first pic my eyes focused on the top corner joint and said Whoa! to my brain. The other thing that struck me was how "plain jane" the design. I get it that it's for a boy but the overall design is really sterile as for esthetics.   I seriously doubt the strength is good as shown. A bed frame that tall has lots of stress on joints. 
How will he exit the bed? Is the one end a "ladder"? That needs to be addressed to decide what's OK with the main frame. 

(FWIW, I made a set of twin beds for our twins along with the same bed as a single for our oldest son. I used 100% true, enclosed, blind tenons for all horizontal members and never an issue. I stacked the twin beds using 1/2" steel pins. I also built a walnut ladder that had steel hooks that engaged the top safety rail as the twins were real young when I made these beds.)

Hickory is very strong but those notched ends will easily break at the short grain. A person up high will cause much stress on the joints. Having the horizontal meet is also weak in the post as shown. Tenons are easy to do based on what we see you've accomplished already. Maybe it makes sense to create tenons on the hickory ends and glue plugs that have some esthetic value into some of your holes? 
Again, I'm sort of thinking out loud not pointing a finger at all. 


Kan=Kansas;tuck=Kentucky;kid=what I'm not

Crusarius

Thanks for your response, I appreciate the thoughts. 

The sterile design really is made up for in the grain of the wood. I doubt this bed wil lever be seen again after it is installed :)

I do agree the short grain is an issue for strength. That is what I broke on two of the long cross members. 

You are correct, the one end that has all the bars across is a ladder. That end is very strong and stiff with all the joints.

I thought about the tenon idea. The biggest thing that turned me away from that is being able to take the bed apart. I know this bed will get moved alot and my house is not very conducive to moving anything big around.

I thought about a through tenon with a wedge driven in to hold it but working with 3/4" material I was a little worried about taking a 1/4" out of the center. in hindsight it probably would have been better than the short grain hook. Plus that would stick out a good deal so it would not be able to be tight to the wall.

Thank you for your feedback. If you got anymore, I am all ears. This whole wood working thing is very new to me. If I was making this out of steel it would be a cake walk.

Crusarius

Just had another thought to at least fix my strength issue on the hooks. 

I could run a sawcut onto the end of the tenon then inset another piece of wood the other direction. 

That will at least strengthen the joint but will still have all the other issues present.

Could also put a steel plate inside the hook. That will definitely fix the strength issue.

DMcCoy

The furniture bolts - the nut - also known as a barrel nut.  You can use a wood dowel instead and a lag screw.   If you used black walnut for the dowel it would add to the overall look.  Lag screws can be painted after a vinegar treatment.
The forces that high up are likely very high.  I have seen similar set ups in college dorm rooms where they put a desk under.
Me- I tend to overbuild.  I would be adding X bracing to all sides but the front.
I have never used hickory except on the BBQ so I have no ideas on the strength of the joints.  The grandfathers barn used an interesting mortise and tenon.  The bottom edge of the tenon was dovetailed and the mortise was cut the same.  The mortise had to be tall enough to accept the tenon and once assembled there was a long wedge driven in to lock the joint in the open gap left on top.
I'm not sure what you have to work with and what your options are at this point.
I like the clean lines of your layout.  Embellishment can be anything from intermittent deeper rounded corners to sculpted cross board tops.

kantuckid

I thought of the wedged tenon after I'd posted. I've done several- one is the dining table which my legs are underneath as we speak-it's now a computer table. It's a trestle table with about a 2 1/2" x 5" trestle that's wedged outside the colonial looking end pieces. It's red oak and thick wood ends too. Another wedged tenon I did is a stool, has angled wide board legs with an angle shoulder on the tenon matching the legs splay and it's extremely strong design because of the angles involved. I copied an antique design in both cases. Another I did was an end table from red oak that has a lower shelf with double tabs and wedged twice on each end.
I think the saving aspect is best done by tossing the end thing that broke on you for a better post connection. 
Bracing as mentioned, might be the easiest to use. 
I once bought a 1,000 BF bundle of mixed species, off grade lumber, (mostly pine & often sold to build race horse stables here) to build a chicken house. Was before I owned a sawmill and in that bunch was some nice wide hickory, I've never found a use for it yet.   
 
Kan=Kansas;tuck=Kentucky;kid=what I'm not

kantuckid

Quote from: DMcCoy on December 18, 2021, 08:30:41 AM
The furniture bolts - the nut - also known as a barrel nut.  You can use a wood dowel instead and a lag screw.   If you used black walnut for the dowel it would add to the overall look.  Lag screws can be painted after a vinegar treatment.
The forces that high up are likely very high.  I have seen similar set ups in college dorm rooms where they put a desk under.
Me- I tend to overbuild.  I would be adding X bracing to all sides but the front.
I have never used hickory except on the BBQ so I have no ideas on the strength of the joints.  The grandfathers barn used an interesting mortise and tenon.  The bottom edge of the tenon was dovetailed and the mortise was cut the same.  The mortise had to be tall enough to accept the tenon and once assembled there was a long wedge driven in to lock the joint in the open gap left on top.
I'm not sure what you have to work with and what your options are at this point.
I like the clean lines of your layout.  Embellishment can be anything from intermittent deeper rounded corners to sculpted cross board tops.
Might simply chamfer/bevel the posts with a router. I'd leave the barrel bolts to IKEA and save yer money. Simple is OK as your son's not gonna care about frills.
Kan=Kansas;tuck=Kentucky;kid=what I'm not

Crusarius

I had several ideas last night. One of them was to route a 1/4" groove into the ends of the boards and glue in another piece of wood with the grain 45 or 90 degrees off from the support board this could also be a piece of 1/4" steel plate.

Option 1 repair Steel or wood plates in 1/4" groove with grain rotated from original



 

Option 2 furniture bolts


 

Option 3 change it up completely and go to a mortise and tenon using furniture bolts to hold it tight. I am trying to avoid this because it means I would have to scrap the boards and start over.


 

I have decided I need to add diagonal braces no matter what. Since the bed is never going to be in the same place twice I am doing my best to make them the least intrusive that I can. Here is my idea for that. The magenta angle pieces are the supports. I think I can get away with them just on the mattress support cross member, I just drew them in on the top to see how it would look.

The way the three joints are built I cannot connect the top rails together. If I use furniture bolts I can connect them all together. Furniture bolts are starting to be more appealing. But still do not want to use them



 

Thanks for all the feedback this is a very new endeavor for me. I am actually quite pleased at how well it has come out so far. Just so you guys know the closeup pictures of my joints were my setup pieces I used much better looking for the actual parts.

Don P

Funny, we were talking about shear failures this morning on a building thread.
In building I have a couple of choices on how to brace something. Since I usually have large sections of wall, an angled brace or a plate or plane of plywood works. If I need the whole wall open, say a pavilion or fully open wall, then the joints themselves need to resist the rotating moment. That usually gets into steel, wood has a hard time with the forces concentrated at the joints especially as the lever arms get long. Furniture is pretty much just scaled down versions of the same thing. The bigger the shoulder the better if it is all wood.

There is a piece of bed rail hardware that is not far from what you drew with the kerfed in plate, several hooks go into the mating female part in the end post. I'm hoping someone knows what I'm talking about and knows the name of that critter.

Crusarius

I know exactly what your talking about for those brackets. It was tempting, but, I am being stubborn and trying to go beyond my capabilities as I usually do on this build :) I may still break down and try those but I definitely need triangulation.

I think I have a really good idea for the bottom mattress support to turn into a very strong structural member that will support the entire bed. Stay tuned :)

Larry

Larry, making useful and beautiful things out of the most environmental friendly material on the planet.

We need to insure our customers understand the importance of our craft.

Crusarius

yea, bedlocks, thats it :) Problem with those is they are held by just screws. Worst yet screws in end grain.

How about this idea?

Option 4: still using same wood clips but more of them and spread out to minimize the moment and twist with triangulation. The upper picture is the full members the lower is just showing the center detail.



 

This would just be on the lower cross member where the mattress sits. It would take way to much to redo the joints on the other two cross members to be able to connect them all together. Even though that would be ideal for resisting moment.

Don P

If the piece in red is wood those hooks will shear or really tension perp, POP! off in very short order.
I'm looking at Lee Valley at a bedlock and bed hook. The bedlock is mortised into the post, the bedhook slips into a groove kerfed into the rail, there is no end grain screwing.

Where steel properties are the same in any direction, wood properties vary greatly depending on the direction of force to the grain of the wood.

Crusarius

So apparently the smallest bed hook I can find is 3.3" my rails are only 3". So I either custom make them or cut them and modify them. or I keep thinking about how I can accomplish this project. 

I was going so good and so happy, then the break and the wind sucked right out of my sails. :(

Ianab

When I built loft beds for the girls I made the posts laminated, from 3 x 3/4" boards. That made it easy to incorporate a very accurate mortise that the ~6" bed rails would slot right into, with no play. The posts extended up past the bed rails to hold head and foot boards, so there are no short long grain pieces that can break off.  There are a couple of screws to hold it secure, but still allow the bed to be broken down and moved.  



 

The mattress base is basically one solid unit, but with the bed "rails" extending 3" out into the posts. I've checked and found 4 teenagers hanging out on it, so it's plenty strong. The desk area below has some solid panels that act as bracing for the whole structure to reduce 'wracking" stress. 
Weekend warrior, Peterson JP test pilot, Dolmar 7900 and Stihl MS310 saws and  the usual collection of power tools :)

SwampDonkey

Wedged trough tenons with shoulders might be an option. The wedges can be removed to break it down. It is a very strong joint. Commonly used for the structure of very large floor looms that have to withstand a lot of forces from weaving. Think of a king sized bed, 6 feet tall. The left and right sides of the frame are solid with mortise and tenon joints, but there are cross members top and bottom of through tenons with wedges that make the structure solid and stable.

Make your head and foot sides solid with hidden mortise and tenon, then cross members are pegged mortise and tenon. She'll be solid. ;D
"No amount of belief makes something a fact." James Randi

1 Thessalonians 5:21

2020 Polaris Ranger 570 to forward firewood, Husqvarna 555 XT Pro, Stihl FS560 clearing saw and continuously thinning my ground, on the side. Grow them trees. (((o)))

Ianab

Yeah, pegs would work for being able to dismantle the bed again. 

Mine were built knowing they had to come into the house in pieces, and will probably have to come out the same way. So I settled for some stainless threaded square drive "pegs".  :( 
Weekend warrior, Peterson JP test pilot, Dolmar 7900 and Stihl MS310 saws and  the usual collection of power tools :)

SwampDonkey

Yeah, I can slide a 400 lb loom across a hardwood floor and remain square. :D :D Now imagine making rugs, and that 400 lb's creeps across the floor with every beat with a force swung behind a 30 lb 'mallet'. Some folks brace the loom with boards from the loom base to the wall baseboard. Otherwise, you have yourself a 'walking' loom. :D :D It can move about 6" when weaving a 40" rug. You have to beat hard to make a good firm rug, not them loose made $5 Walmart rugs from Asia.
"No amount of belief makes something a fact." James Randi

1 Thessalonians 5:21

2020 Polaris Ranger 570 to forward firewood, Husqvarna 555 XT Pro, Stihl FS560 clearing saw and continuously thinning my ground, on the side. Grow them trees. (((o)))

Crusarius

Ianab, you corner posts sounds like mine except I left a wire chase through the center.

You guys are right on top of things. While laying in bed last night I think I came up with a way to use the existing everything and just add pegs to it.

You guys thing a 1/4" x 1.5" peg will work? it will bull fully encapsulated so the only shear points would be at the seams. I don't have time now, but I will draw it up when I get back.

kantuckid

Steel surface plates as mentioned? Look at the Woodworkers hardware on New Mexico Woodworkers Supply? Bed hardware is out there several places with steel bedrail connections. I've mostly preferred/used  steel bed rails using carriage bolts through large wooden bedposts on my own bed builds. Lots of stress, even on a low to the floor, bedrail to post connection! Less when you get to be my age... :D
Given the slots are already in the posts it's harder to wrap my brain around a solution. 
Kan=Kansas;tuck=Kentucky;kid=what I'm not

Crusarius

ok, here is a quick and dirty sketch for the peg idea I was thinking about. The pegs are not that big but since all of the seams between the material are very tight the only shear point would be at the material interface seams. Hopefully I will still be able to drive the pins in and out and still get a solid bed. Not sure I have anything to lose right now.



 

I may change up the red part to not have the hooks but I think I may keep the hooks so I can assemble everything and then add the pegs after its all standing.

Crusarius

Well, I just decided to try my idea.

Keep in mind these are template pieces so they are ugly :) The single board with the pin in it represents the inside part of the leg. there would normally be one on the other side but I only had that single piece available.

This joint is definitely more sold and if I have 3 on each end  on each side then that would give me 12 solid points that would need to break. and with the exception of making the peg the grooves are easy.



 



 



 



 



 



 



 




Crusarius

and for some reason I decided to test my joint I created. I set the end on the table and began hitting the end of the hook with a dead blow hammer.

The peg held up very well. The rest, not so much... :(







  

Bummer. I guess back to the drawing board.  

Crusarius

Now what I did notice when I was working on some other ideas, when I put a wedge in to lock the lower support in place the torsional rigidity increased exponentially. Almost makes me wonder if I had started there if I would have been ok. of course now I know my weak spots and will not trust my kids to them.

Man this responsible parent thing sure can be a drag :)

chet

My favorite way is to use mortice and tenon joints. Then bury a nut in the rails and lock it in with a counter sunk bolt through the post. Then finish off with a removeable wooden cap. Strong, easy to disassemble, and best of all, it's cheap.   :)
I am a true TREE HUGGER, if I didnt I would fall out!  chet the RETIRED arborist

Thank You Sponsors!