Coffee Tables with a Glass Top

These table designs are the outcome from an iterative sketching session.  The construction details are simple and style independent.  I've made 3 different styles of this system with different legs and wood choices that all are put together the same way.  The variations were inspired by a former student's research project. Her hypothesis was that age, gender, socio-economic status, and a few other factors would influence style-based buying choices.

I call this one Chéri.

Cherry Legs. Wax Finish

Simple Construction

Cherry Top.  Oil Finish

The legs of Chéri were also an outcome of their own iterative sketching session. The height of the foot is the same as the gap between the glass top and the wood top. The upper curve (a French curve) if continued down would end at the inside corner of the legs. I've made copies of this design out of hard maple with a birds eye center strip and red oak with a curly oak center strip. Both have found their own homes.  This cherry version was the original prototype.  The finish on the legs was an experiment which I don't care for. Plywood templates of both the front and side curves of the legs make it rather easy to duplicate the legs.  The two that I sold had a nicer glass top with an ogee edge to compliment the French ogee edge profile on the wood top.  Having a transparent top encourages featuring more interesting wood grain on the shelf below. The shelf is also a good place for seasonal or thematic décor. 

This one is Savanna.  Where Zebras roam.

Zebra Legs

Simple Construction

Zebrawood Center

I used a photo of Zebras to help inspire the shape of the legs. Zebra wood is rather busy when used in wide panels, so the top is a center strip of Zebrawood with quarter sawn white oak strips on both sides that the legs appear to run through. 

The third design was simpler with square post legs and made from red oak. "Country" might best describe the style. Red oak with a cherry stain. My parents chose it out of the three designs and it was handed down to my oldest sister. She enjoys it. I don't have a photo of this one but below is a rendered image of what it looks like without a glass top.

All versions normally have silicon pads atop the legs which both keeps the glass from being bumped out of position, and covers the top of the bolts that keep the top and bottom sections of the legs attached to the wood top.  

So which design do you prefer?  I'd love to know and if you don't mind sharing your age and gender that data would add to the data the student collected.  

4D

Comments and questions welcomed and encourage.  

Cam Levers vs Twist Knobs

The longer I use a jig or a fixture, the more likely it is that I'll find a subtle flaw or a feature that could be improved.   The Angle Clamping Fixture I have on my CNC works fine, but is a little finicky to lock in place to set the angle. I used two twist knobs to tighten the fixture position.   They worked, but would occasionally bump the fixture angle as they rotated to get tight. 

My Compound Angle Clamping Fixture

When I made the Bridges I now use for spanning my CNC bed area I chose cam levers to lock down the ends quickly.  I am extremely happy with how quickly I can loosen, reposition, then tighten down the bridges using the cam levers. 

My Bed Bridges

It took me awhile to realize again the value of cam levers.  When a jig or fixture works OK it doesn't beg for small improvements.  An email add from the company I bought the cam lever for the Bridges from provoked me to wonder if anyone sold a size I could use with the existing 5/16-18 bolts on my clamping fixture. Apparently yes. 

Cam Levers at Amazon.com

When these cam levers arrived they included 5/16-18 T-bolts that were too long. The hex bolts I'd used were too short for the cam levers.  The fix required CNC cutting a pocket for the oval head of the t-bolts, and cutting down those bolts with a hacksaw.

Improved cam locking

What used to take several turns of twist knobs to unlock then relock this fixture now takes flipping two cam levers to loosen or tighten.  

Router Fence

The fence I have on my bench mounted router is another place where cam levers make adjusting it quicker and easier.  I had some cam levers on hand that would work with the 1/4-20 T-bolts.  The bolts were too long though and had to be cut shorter with a hacksaw.  

Cam Release

Cam levers are available in many sizes. As I revisit many of my shop fixtures/jigs/tool fences that use twist knobs it is apparent that cam levers would improve the simplicity of using them all.  As I look back on the furniture projects I've done over the last several decades I realize that cam levers have been the ideal solution many times.  One example was a chair design with an adjustable seat that would slide forward or back for the user. Back then was before there was an internet and I made my own cam lever from an aluminum block using a milling machine as well as a few other shop tools. 

4D

Comments and questions are welcomed and appreciated.

 

Scraps. A Window Table made from Assorted Workshop Scraps.

Scraps

This table came to be from my desire to use up some assorted material scraps I had in my shop.  A vinyl wrapped particle board 18" wide shelf scrap became the table top.  A scrap of hickory that used to be one side of a wall mounted shelf became the drawer front. The angled ends of the drawer front inspire angling the ends of the back stop above for some detail continuity. The knobs on the drawer front are located where there were two screw holes to cover. Some old growth pine was used to cover the edges of the base which was made from 3 pieces of cheap plywood. The cheap plywood was painted black to diminish it's visual impact. 

Smooth running drawer.

The drawer hardware rollers were salvaged from old cassette tapes.  A Teflon spring loaded guide t-pin was embedded into the back edge of the drawer to run in a t-slot and keep it from racking when pulled out or pushed in. 

The top of the base sides slide into dovetail slots in the bottom of the table top. The center panel slides into dovetail slots on the inside faces of the two sides. This table can be quickly disassembled for relatively flat storage or moving/shipping. 

The construction is simple.  The details make it look more interesting.  A nicer version could be made from solid wood rather than MDF and cheap plywood, but wouldn't be any more useful.  I had this table on display in a gallery show of my work and was surprised how much interest it attracted. 

Without all the detail the 4-plane assembly (2 sides, a center plane, and a top) is a quick and simple way to make a table (of nearly any size) from sheet goods. The center slips down dovetail slots in the sides. The sides slide into dovetail slots on the underside of the top. 

24" x 24" x 24" four plane table

With some thoughtful reflection even a pile of scraps can become a nice looking useful little table. 

4D

Comments and Questions welcomed and encouraged!

Versatile Coffee Table Design

This design I came up with many years ago.  It is a simple table design composed of two wood leg boards and a wood beam for the base, with a table top board to rest on them.  The identical base boards have an offset 3.0625" wide hole through them that the rectangular beam easily slides through.  The boards (legs) lean on the beam. An example of my pursuit for simplicity in designs. 

What I didn't realize until I first assembled the base was that there were several ways to assemble it. 

Opposing legs

By flipping one leg you get another stance. 

Parallel legs

Flip the base assembly upside down with 2.125" wide and 3" tall beam lower and you have two more looks. Beam high and beam low.

Beam Low

Flip one leg upside down relative to the other leg and with the beam at an angle it changes the height of the table. Tip the legs to the other side and you have another table height.

Beam angled. Table taller.

Beam angled.  Table shorter.

Version 2 changed the hole shape so I could turn the beam sideways.  Doing that you'll end up with 16 unique stances and 6 different table height options.  Image above shows the legs angled to result in the maximum height position. Tip the legs to the right to get the minimum height position with the beam oriented up. Twist the beam 90 degrees for an even lower table height.  

The key is the rectangular beam cross section and the hole that allows it to slide in standing up or laying down. With some drafting iteration the hole and beam size could be tweaked so the different heights of the top were steps between 14.5" and 18".  

The only weakness in this design is that the table top only rests on the base. There is no alignment strategy or interlock between parts that would allow picking up the table by the top alone. The loose top can be flipped over, and one side could have a game board inlaid into it.  Scrabble or Checkers/Chess or Chutes and Ladders maybe?  Make a recess and glue in an actual game board, or use different colors of wood and V-Carve inlay each

square of the board into the top. 

As the stance and table height of this table can be changed easily by re-arranging the 3 base parts it is a great example of 4th dimension design. A design that over time may look different and vary in usefulness. 

4D

Comments and questions encouraged and appreciated!

Leaning Bookshelves

I needed some shelves.  

One idea was to screw some shelf standards to the wall, hang brackets onto them, and set shelf boards onto the brackets.  Pitfalls of this idea include the need to screw standards into the wall. This also results in shelves that are adjustable in height but stuck in one location. 

Another idea was to make a book case. A box with a face frame, sides, bottom and top, and back to house the shelves. Pitfalls of this idea was all the material needed that didn't actually help to hold up the shelves, and relatively complex construction.

My compromise solution is a simple 2ft wide and 6ft tall face frame with shelf standards screwed to the back of the 2" wide sides. At the center of the 2.75" tall top stretcher a 1.5" x 1.5" post runs from the frame to the wall.  10" deep oak shelves rest on brackets hooked into the standards. The face frame stands vertically and is kept 10.5" from the wall by the top post.  The shelf "leans" because with all the weight behind the face frame the loaded shelves are truly leaning against the wall.  Shelf positions are adjustable up or down. No connection to the wall is required.  Bottom stretcher is 4" tall. Stretcher ends tenon into mortises in the sides. 

Post and shelf standards

This shelf has seen regular use since it was built.  Being just 2 feet wide there are several minimally 2' wide wall sections in my house where this shelf could be placed.  Right now the shelves are installed in the corner of my bedroom next to the door to the closet. That corner, blocked by the closet door when it is opened, had no other potential value or use. These shelves perfectly fill that space. 

Shelves shown.

Four shelves, 17" on-center, are show.  For just books another shelf could be added with 13" on-center spacing. Shelves for books could be U-shaped with vertical ends to prop the books against. The wall behind is the backstop for anything put on the shelves. 

Carpeted floors usually have a tack strip under the carpet next to each wall. Furniture set next to the wall will tip forward slightly due to their back feet resting on that tack strip.  These leaning shelves don't have back feet.  They avoid dealing with the tack strip and any baseboard trim.   The bottom shelf can be placed just above any baseboards. 

Amazon link:  60" Standards and Brackets.  Choose brackets for 9" wide shelves.  I drilled a hole in the bottom of my shelves, roughly one inch from the back edge, for the tip of the brackets to register into.  Black brackets and standards hide in the shadows for a more discrete look.  I also made two notches in the front edge of each shelf to slip around the projecting shelf standards.

Shelf with front edge notches

The images above are generated by my CNC software which has limits on how detailed the parts shapes can be and combined.  Missing are the fairly standard shelf brackets that would be hooked into the vertical standards and support each shelf from below. 

If there is a safety concern that children might try climbing up the shelves then the top post end can be fastened to the wall with an L bracket so the shelves can't fall back.

4D

Comments or questions welcome and encouraged.  

Using a CNC to solve unusual woodworking challenges.

Do a search for what a 3-axis CNC is capable of, and generally you'll find people cutting flat work on their CNC bed. Some have a radial 4th axis to do simple or complex cylindrically confined projects. Most come with limits describing the width, length, and vertical cutting range projects should be confined to.  Many CNCs are capable of solving far more woodworking challenges, but you'll need to literally think outside that cutting limits box.

In 2004 or so purchase my own 3-axis CNC Shark. I cut flat parts for student furniture designs in my garage for the next few years. Bumping into the area limits of this small CNC, I purchase a larger Probotix CNC for my home shop. A desire to cut tenons on the ends of long stretchers led me to open up one end of my Probotix CNC for vertical access down to the floor. Once opened up, I realized with some jigging I could clamp parts at angles other than 90 degrees. Four or five revisions/updates of my compound angle clamping jig have led me to what I know can be done today.  What a CNC can do doesn't stop at the spoil board plane. 

Opportunities arise when you think about using more than just the flat bed of a CNC to clamp your parts to.   Many come with 2 motors pushing/pulling the gantry, which may mean there is nothing running under the bed.  Once you consider using the space under the bed, the next step is to make access to it. In my case I initially left open the front 1/4 of my CNC's bed, and mounted the CNC on an open frame with no top on it.  I now have access to all the vertical space between the bed of my CNC and the floor.

With access, the next step is to come up with a way to clamp parts under/inside the frame to hold them rigidly where the CNC can reach the areas that need to be cut.  

If you clamp your parts or jigs to one of the frame rails, make sure the rails are securely mounted and can't be rotated or racked or bent or flexed when under load. I made a jig that clamps to the front rail as I knew it couldn't rotate the way the frame is assembled: My Jig 

Bridges that span the frame, clamping jigs, accessory rails, and even the frame rails themselves can contribute to the potential woodworking challenges you can solve with a CNC. Bridge support.

T-slots, either in track strips you can buy or the frame member extrusions themselves come in very handy for attaching jigs/bridges/cross rails to.  One example is my bridges that screw into t-nuts in the frame rails and themselves have t-track down their middle to use for clamps that hold your project boards down. Another is my advanced compound angle clamping jig that bolts into the inner face and top slots of the front frame rail.  Sections of t-track could be installed on such a jig, but my current version has holes for c-clamps to hold project boards and reference edges/stops to. 

It is below the bed where opportunities for creative CNC cut solutions live.  To take advantage you'll need creative jigging to clamp your project parts down there.

4D

Comments and questions encouraged and appreciated!

The value of Iteration and Prototyping.

Iteration:  As it relates to design, iteration is a sequence of sketches or models, with each intentionally a little different than the previous one. The iterative sequence continues until one reveals a functional solution not previously discovered or imagined.  A useful iteration may then become the base for a new iterative sequence that looks to solve an additional problem or add a new function or simplify the basic detail. Aesthetics may also be the goal of iteration, with each step seeking a better aesthetic. A refined composition or shape.

Prototyping:  Making a sample of an initial idea often reveals something about the idea that could be simplified or improved.  A sample may reveal flaws that can't be deduced from a sketch.  Prototyping iteratively, compared to sketching iteratively adds testing and interaction with and manipulating the design at each step. While not every product needs exhaustive modelling the best way to discover an unconsidered function or flaw is through iterative actual (not virtual PC) modelling. 

3D printing is one way to produce samples of a product idea.  I've had an idea for a jig that could be used to help install another hardware product I invented.  My initial idea was for a jig with a critical variable fixed in position.  Once 3D printed I was able to test the initial jig idea, and it revealed to me the value of making that fixed detail into an adjustable detail.   A new prototype was designed and printed that allowed the position of the detail to move.  It revealed that a way to lock the detail into position would eliminate the need for an accessory clamp to hold it in position.  A third prototype was printed to stiffen up the back plate of the jig.  It also modified and simplified the insert end to ease insertion and get out of the way of the drill bit being used.  It is not unusual that it takes 3 or more prototypes before homing in on the best solution. Often the early prototypes reveal opportunities for improvement that weren't obvious or initially considered. 

Base Drawing:  If whatever you are designing has some known, fixed properties that won't change through iterations, then a sheet of copies of just those properties drawn can help you iterate though variations efficiently without accidentally changing a fixed property.   This base drawing can be copied many times before starting to draw over one.  In an array of sketches an accidental line may be the spark that reveals the path to a great solution.  One danger of NOT using such a base drawing is that one or more fixed details may be forgotten in an iterative sequence. Another danger is that a concluding solution may no longer work when adjusted to account for the known fixed properties.  I like to sketch on graph paper as the uniform grid lets me maintain the same scale and dimensions of each iteration for accurate comparison.

Elevations views are a good place to start with iterations of a table design.  As a table will have height, width, and depth then 3D perspective or isometric views are recommended for final aesthetic refinement.  Minimally you should work with orthographic front, side, and top views of a design at the same time.  I've seen many furniture designs that looked great in one elevation, but looked awkward in perspective reality.  Design continuity breaks down when the shape of a table top looks unrelated to the base beneath it.   In life we rarely see just a direct elevation view of a product.  Try to anticipate how a design will be viewed when approached and iterate through perspective views from that approach viewpoint. 

4D

Comments and questions are encouraged and appreciated!

CNC cut Holes and Plugs. Simple or Fancy

Holes.  Anywhere.  Any size. Nearly any shape.  Absolute positioning.  

When a simple hole in a panel is needed and you don't have the right Forstner bit or hole saw or paddle bit to cut the hole, the CNC can be used as a drill press. When you need the precision of a drill press but your board won't fit on the drill press the CNC can provide a solution. Your CNC cuts what you want relative to the 0,0,0 home point you have set both in your drawing used to create the tool paths and on the board where they will be cut.  

Holes.  Precisely Positioned

The standard strategy when laying out cuts is to set the home/origin point at one corner or the center of your project board. Shapes are assigned coordinate points relative to that 0,0,0 origin.  In your CAD software draw a circle the size of the hole you want, being sure it is centered around 0,0,0 on your drawing. The size of the holes can be precisely measured down to the precision your CNC is capable of, usually .001" or ,002". Create and save the profile or pocket tool path to cut it out. Now at the CNC, simply move the bit to any center mark where you want that hole.  Zero (set to 0,0,0) the machine at that point.  Run that hole tool path file.   You can move , re-zero, then cut the same hole as many times as you need it now without going back to lay each out on the overall board. Cut the same hole at different centers, on different boards. Router end mill bits are commonly available down to 1/16" in diameter and 1/4" to 5/16" in cutting length.

If you need an array of holes, aligned or offset from each other, the CNC is also the best tool to carry out that task.  Most CAD drawing software have an array layout tool. Typically you draw just one hole outline where you want it, then use the array tool to have it copy that outline as many horizontal and vertical places as you've told it to.   

This is good for through holes so long as you have a long enough router bit. Also great for flat bottomed holes with no center divot that Forstner or paddle bits usually leave. It also works for dowel holes no matter how much your dowels have swollen or are out of round.  You can even make slots for Domino loose tenons anywhere on a board using a CNC. 

Slots for Domino Floating Tenons

Some CNC controllers have geometric primitive shapes (circles, squares, etc.,) built into them for easy/quick cutting without using any CAD software. 

If you have a way to clamp your boards/project at any angle/compound angle underneath your 3-axis CNC then holes can be "drilled" at nearly any angle through them. The limiting factors are bit length, Z axis travel, and spindle/chuck angle clearance above the bit.  

Perfect Wood Plugs. You can buy plug cutters in a variety of fixed sizes.  But when you've accidently picked up a 11/64th drill bit for your counterbore instead of the 3/8" bit you intended to use you most likely won't find a plug cutter for the resulting hole.  With a CNC and a scrap of wood to match or intentionally contrast your background wood just draw a circle the size of the plug you want and then use 1/8" or 3/16" end mill to profile cut it outside the line. Don't go much deeper than you want your plug to be in length, then you can pop the plug free with a screw driver.  

Plugs. Precisely Sized

Tapered Holes.  To ensure a tight fit you could even taper cut these plugs. The hose attached to most shop vacuums has a tapered end on it. When making jigs or connecting adapters to attach that hose to, a straight hole makes an imperfect (loose) opening for that tapered plastic end.  The fluting tool path or the moulding toolpath in Aspire and VCarve Pro can be used to taper the perimeter of any hole. Match the tapered hole in your jig/adapter to the taper of the hose end and you'll have a snug fit that won't vibrate loose or pull out easily.  You can even use the CNC with a circular array of short vectors and the fluting/moulding toolpath to make perfect tapered holes for small tapered alignment pins. Making a chair composed of spindles and planes? Consider tapering all the spindle ends and holes they plug into. Done right the joints will continually wedge together under normal loads.

Comments and questions welcomed and encouraged!

4D

Unusual Furniture Properties to Consider

Often a furniture design looks fine on paper (or on a computer screen), and performs fine when assembled in the shop. What many designers fail to consider is the scenario of use it will see as it resides in your home or business over time.  It is those that encounter it when in place that often discover undesirable qualities or properties over time as they interact with it. Here are a few properties that my design students have encountered over time where their furniture demonstrated an unexpected flaw or two.      

- Can you vacuum under it?  

- Is it top heavy and prone to tipping? Do you have a cat that might knock it over?

- Can tables survive being sat upon?

- Is it jiggly?  Long legs on a tall table may look best with no other stretchers or connections below the top.  Flex in the legs may not lead to structural failure, but will likely let the top jiggle a little when touched or bumped. 

- Can one person lift it or move it easily without disturbing what is in or on it?

- Is it appropriately sized for where it resides and what it holds in your home or apartment? 

- Is it easy to clean?  Grooves or joint gaps in a table top may add interest to the overall composition. Experience will reveal those grooves catch dust and crumbs and spilled liquids or just the condensation off a cold drink. 

- Does the coffee table have clearance for your shins and toes when you sit next to it? 

- Where it lives is there room for drawers to slide out or doors to open up fully for access to the contents?

- Does it travel well?  Can it be strapped down without failing?  I have furniture that has survived being moved from house to house several times.  I also had a few pieces that didn't survive those moves. 

- Are the wheels or casters an appropriate type and sized right to roll easily on the floor surface the project will live on?

- Does what it is made from react badly to dog urine?  Cleaning 

- Can it be repaired easily should it break?

- Does it mind being set where sunlight falls on it?  Will sunlight discolor or bleach it?

- Could it survive being stored in an unheated or cooled garage or attic or storage unit for a few years?

- Will the surfaces see abuse from normal use?  

- Can it be refinished or touched up easily?

- Will it wound you if you bump into it or fall on it?  Sharp corners at shin height?

- Could you trip over protruding legs?

- Is it child or baby safe?  

No design will have to deal with everything listed above. Miss one that the design should have considered more thoughtfully and it may live a life less loved. 

4D

Comments and questions encouraged and appreciated!  

Furniture Designs with a 4th Dimension.

Why "4DFurniture"?  

Most of the furniture designs of mine I've posted here are static 3 dimensional shapes. You can measure their height, width, and depth with a tape measure.  They all exist through time, which I consider a 4th dimension.  No matter when you encounter these 3D designs they will be the same as they were at any other time. No changes over time. Stuck in the 3D static world.

Many of my other designs have an obvious 4th dimension. Viewed at different times they may appear different. Folding chairs or folding tables have a simple 4th dimension state.  At times they may appear unfolded.  At other times they may appear folded up. Easier to store or carry or ship when folded up. Useful when unfolded. A dual state 4th dimension. I have won 4 national 1st place furniture design awards and all of those designs had an obvious 4th dimension. The folding or transitional features made them more memorable and interesting to the judges. All had at least one alternate useful state. Among the competitors at each competition no projects had more than 3 dimensions.  All were beautiful designs but were 3D and static. Never a reason to video record them transitioning over time. 

I have two work tables in my garage shop.  From a quick glance they appear identical. One however I have modified so the legs beneath will fold up flat against the top.  While I haven't had a need to fold it up yet, it does have that potential 4th dimension state just waiting until I move.  The other work table will always be the same 3D shape where it is or when it is moved into a moving van. That is unless I get around to modifying it before moving. 

I have a few designs that can be set up in different ways and are useful in every assembled state. One example is a simple trestle coffee table I designed.  The base is two planes of wood, each with a rectangular hole in them, and a rectangular wood beam that slips through the holes.  The top is a simple plane of wood, but could easily be a plane of glass. The 3 base pieces can be put together in 16 different configurations to change their aesthetic stance.  Six of the configurations change the height of the top.  All parts disassemble down to pack easily into a flat box. A 17 state 4th dimension. Link:  Multable

My most versatile design has a nearly infinite 4th dimensional state potential. It is a shelving system composed of 9" wide solid wood panels, 24" wide wood frames, 23.25" wood shelves, and a few other accessories. Panels and frames are held together with snap on 360 degree flexible hinges.  The system can be re-arranged to fit somewhere in most homes.  It can even be divided into two separate sets and used in two places.  I've used it in two homes as a room divider with shelves on both sides and ambient lights in the top of the shelves to bounce off the ceiling. Also as a media center with storage for DVDs and CDs and a TV and media players. It is now a row of shelves along the side of my dining room that wrap around a closet bump out, down the wall, and terminating square against a 68 degree corner.  

If a design has an open arbitrary parameter such as final height or potential to be moved around frequently then these are opportunities to add a 4th dimension state.  Rather than design a static one-height table, come up with a way to adjust the table height within a reasonable useful range. If the design is likely to be moved frequently then consider a state where it is easier to move than when in it's most usable state. I designed a heavy computer cabinet many years ago that I knew would be moved between semesters. I added two front corner 100mm poly scooter wheels and a lock for the doors so the  cabinet could be locked and tipped forward and then easily rolled to another place. Very stable when standing vertical.  Easy to roll and repositioned when tipped forward. 

Furniture that rocks or demonstrates any other dynamic attribute, and is best recorded when captured as a video rather than a still photo has a 4th dimension. Common rocking chairs are one example.  I strive to design a little table that might rock or wobble, but always keeps it's top horizontal. Why?  I currently have a static 3D tiny table next to my chair that holds my phone and smart watch for charging. Where it stands my phone and watch are easy to reach and the table doesn't interfere with the rotation of my desk chair. The table does slightly block access to the front USB ports on my PC. If the table could just rock or tip back a little without falling over that 4th dimension property would eliminate that one subtle flaw. Hardware for a prototype design is on order.   

Desks that can mechanically rise from chair height to standing height have a 4th dimension.  As the height can stop anywhere between top and bottom limits the useful states are variable but not dynamic.  You don't normally use the desk while it is moving up or down. 

A two piece table base of cubic blocks or frames could be tipped to support the top at 2 or 3 different heights. The challenge is finding 2 or 3 useful and practical heights from one base.  I've toyed with creating a table base for a small kitchen island.  The base would support the top at counter height (36" typically), and tip to support the same top at 29" or 30" to use with regular chairs as a dining table for 1 or 2.  Tipping the base though eliminates making use  of the base for kitchen storage. I considered a design that had end sections that folded down. The base would be 29" tall but the top would be 36" tall when the ends were folded down.  Lift up the ends and the top lowers to 30" high with the ends extending out.  This might work, but I'd prefer a solution that had the whole width of the table top available at both heights. Borrowing the mechanical lift from the desk mentioned above may be the best solution. Press and hold a button to move the top from dining table height to counter top height. Plugging it in would be the challenge. For most the solution to using a kitchen island as a dining table is to add bar height chairs to it.

All the examples above with dual or multiple useful states have a 4th dimension. Useful 4th dimension states can be found by considering/imagining the scenarios of use for a design. I was in college and changed residence nearly every semester when I designed 3 of my award winning furniture pieces.  I knew these pieces would be moved frequently and could benefit from a more portable state.  Persistent iteration with these dual states in mind led to elegant and award winning solutions. 

4D

Comments and questions appreciated!