Introduction: Compass Table

One day I was playing around with a compass and a magnet noticing how much fun it was to manipulate the compass rose as I moved the magnet around.  I'm of the mindset that when it comes to fun, more is usually better, so I rounded up 500 compasses and some rare earth magnets and decided to turn what started as just a little silly but entertaining play time into an actual piece of furniture.  

The compasses are inlaid into a custom table top underneath a piece of glass.  The coasters were made to match - they also provide an inconspicuous home for the powerful rare earth magnets that affect the compasses. 

Now I always know which way is north, and exactly where my cup of coffee is...er, so long as it's always on my compass table.

**Note, the reliability of compasses in mass quantities and close proximity decreases somewhat since compasses themselves are magnets.  It still works, and actually results in some pretty cool patterns, but if you're looking for the table to be 100% accurate, I'd recommend not designing a table that places them so closely together.  I'm a big fan of the way the table came out, as it's a toy just as much as it about the science of magnetism.**



Step 1: Materials

To make a compass table you need supplies for the top, the legs, and the tools to put it together.

Table
  • 12mm sanded plywood
  •  table legs - I used 4 Ikea Vika Oleby prefab legs
  • 16 7/16" x 1/8" thick glass circular top (I had this custom cut)
Coasters
  • a couple square feet of 6mm sanded plywood
  • 2 cork coaster inlay
  • 2 rare earth magnet
Compasses
  • approximately 500 "mini compasses".  I got mine for around 20 cents a piece off Ebay.  It takes 500 20mm compasses to cover a 16.5" circle - crazy I know!
Tools
  • router
  • circle jig
  • drill
  • wood glue
  • brush
  • polycrylic - water based clear satin wood finish
  • speed square
  • clamps
  • random orbital sander

Step 2: Modify the Legs

The Vika Oleby legs from Ikea look cool and aren't *too* Ikea-trashy, so I saved myself some building time and went for them.  The circular table that I built is a bit too small to fit them all on there in their store-bought form so I modified them slightly. 

Using a speed square I marked and cut two 45 degree lines on the end of the table leg where it mounts to the the table top so that I could fit 4 legs on my 18" table top.

I removed about 1.5" of material off the corners...no need to be precise here so long as you don't affect the mounting bracket.

Step 3: Route Out the Tabletop

The table top is made from three different layers of 12mm sanded plywood in order to get the right depth for the compasses and overall table top thickness.

Two 18" circles were routed out using a Jasper Circle Jig (a tool that I'm quite fond of).  A third circle of the same size was cut, and then had a slightly smaller circle inscribed inside of it to create the rim for the table.  The rim turned out to be 1/2".

Step 4: Glue and Clamp

I used a brush to spread some wood glue between the layers, stacked them all up centering them carefully, and then clamped and weighted the entire sandwich between some stiff maple boards until they dried.

Step 5: Sand and Finish

Once the glue dried I used a random orbital sander with some 220 grit paper to smooth everything out and take off any rough edges.

Then, I brushed two coats of polycrylic, a Minwax brand water based clear wood finish, that's a whole lot easier to clean up and is more forgiving than Polyurethane onto the table top. 

I sanded lightly with 220 grit paper in between the two coats for a nice smooth finish.

Step 6: Attach Legs

With the table top finished, it was time to mount the legs onto the table. 

Using the supplied mounting brackets as a guide, I marked and drilled the mounting holes for the legs into the top. 

The supplied Ikea allen wrench tightens the bolts into place.

Step 7: Arrange Compasses

If the table were a square or rectangle I would have arranged the compasses in a grid, but since it was a circle (to match the circular form of the compasses themselves), I had to come up with other arrangement options.  After fiddling around with them for a short while I was able to find something that worked well - concentric circles.

Arrange the compasses as tightly as possible working from the outside in, getting the final few in place takes a bit of a massaging, but once they all go down, it's a nice symmetrical tight fit that can adjust to whatever size circular table that you have.

Step 8: Coasters - Route Out

The coasters are made in almost identical process to the table top itself...just smaller. 

One base circle was cut from the thinner 6mm plywood and then one ring was created to become the coaster lip.  The ring is a bit more tricky to route then it's big brother was with the circle jig because it doesn't have enough friction to hold it self in place as the router passes by.  A little tape does the trick so that you can complete the cut.

The rare earth magnets that I bought were 3/4" by 1/8" thick, so I routed out a small inset for them in the coaster base using just my eye, since that hole was going to get covered up anyway in the next step with the cork coaster pad.

When you lay the magnet down in its pre-cut hole, make sure that you've got the pole facing the right way, we want to attract the north end of the compass, so flip it around until you've got it the right way.

Step 9: Coasters - Glue and Clamp

Spread glue on the rim of the coaster and the coaster base and make a coaster sandwich.  The cork pads can be cut, or, pre-bought from Ikea as well and glued into place inset within the rim in order to cover the exposed rare earth magnet. 

Clamp them between some of those pieces of maple from before and allow them to dry.

Step 10: Coasters - Sand and Finish

Once the coasters were dry I sanded them smooth with some more 220 grit paper and put two coats of polycrylic on them as well.

Finding things to dry them on is easy since they've got a magnet embedded in them...

Step 11: Glass Top

I was toying around with the idea of pouring epoxy or polyester resin into the table top to finish things off and permanently secure the compasses into place, but upon learning more about the process, I decided that cutting a simple glass top would be safer since I didn't want to jeopardize my 500 compasses in case something went wrong with the resin pour.

I got the glass cut at East Bay Glass at exactly 16 7/16" so that would perfectly fit inside the rim of the table.  It sits directly on top of the compasses nicely and has virtually zero play.  As a result, I'm not worried about scratching the tops of the compasses, but if whatever you were inlaying was more vulnerable for some reason, putting in some kind of supports for the glass could be a good idea.

Comments

author
T0BY (author)2015-12-08

This Instructable clearly has direction!

author
Mr AbAk (author)2015-02-13

Awesome Ible.....

author
Bradin4945 (author)2014-07-14

What about adding wheels so you can turn it and all the compass arrows turn

author
jdoorenbos (author)2014-05-29

Very neat project! I love the simple and subdued look of the table. Have you considered putting small magnets in the bases of the coasters? It could be a fun way to visualize magnetic field lines!

author
noahw (author)jdoorenbos2014-05-30

Check out step 9 - the coasters have rare earth magnets embedded right into the bottoms.

Thanks for the feedback!

author
009agent made it! (author)2014-01-31

Finally finished my version! Thanks for the inspiration.

DSC_0338.JPGDSC_0339.JPG
author
shazni (author)2013-09-28

oh wow! That's so cool

author
mmorpgs (author)2013-03-24

Interesting project, thanks for posting it. I originally thought it would be a table with a homemade compass under it, but now I see it is 500 compasses lol. Have you tried making your own large compass?

author
funvill (author)2012-08-30

Here is my version I made for the Vancouver Maker Faire 2012
http://www.abluestar.com/blog/wp-content/uploads/2012/08/IMG_4790.jpg

author
noahw (author)funvill2012-08-31

That looks awesome! Did you modify an exiting glass top coffee table? I'm so glad that you decided to replicate this project and post a picture of the finished tab. Seriously - nice job.

author
jcbeaver7 (author)2012-08-15

This is the perfect idea for my woodworking class! Thanks!

author
vincent7520 (author)2012-06-21

Neat ! …
I also like the music playing on your video : very 50's !!!… cool.

author
christyoates (author)2012-01-11

This is fantastic Noah, great video too!

author
playful-geometer (author)2011-10-24

I saw this on a TED talk about the importance of sabbaticals, I wonder, are you that guy or did you both come up with the same idea ? I heard about an interesting phenomenon of Multiple Discoveries in a recent talk by David Wilcock

author
RadioactiveBees (author)2011-08-06

:D awesome! at first i thought it was a giant compass as a table :P

author
Electronics Man (author)2011-07-20

Great Job!!!!

author
xavec (author)2011-07-15

This is just outstanding. Top marks for thinking - as wiggins said below - hilariously big. I'm a total sucker for Epic Scale Silliness combined with good craftsmanship, so this sir, is a WIN XD

author
wiggins8472 (author)2011-07-07

Hilarious. Well done.

author
triumphman (author)2011-07-02

Dude, that's a lot of compasses! You'll never get lost!

author
mpino (author)2011-01-21

Fantastic! We're going to make one the nature center where I work, to help teach kids about the earth's poles, and orienteering, etc. Also, it's just a great toy for kids to play with!

author
mpino (author)mpino2011-03-23

aaaaand: we did!

IMG_1820.JPG
author
The Porsche Fan (author)mpino2011-04-21

Nice table! Looks good.
After calculating the cost of the compasses, I can totally see why you arranged them that way

author
0jack (author)mpino2011-03-24

That is FABULOUS! Great use of the 'Ible.

author
Skylberg (author)2011-03-18

I agree with Muller....Want, want, want, want!

author
jimopertrat (author)2011-02-13

mate that is totally AWSOME!!!!

author
simi-kilr (author)2011-02-06

Nice project. Where can you find cheap glass?

author
nerys (author)2010-12-30

Ok thats just plain cool. I am going to have to do one of these one day.

as for sources of compasses? go a little nuts and even smaller compasses

http://www.dealextreme.com/details.dx/sku.4519

$2.54 shipped for 20 of them. figure what? 1500 of them for this project? $190

would also be cool to use different compasses IE one in the center much larger or spaces around to form a nice pattern

here are some of the cooler ones I found.

http://www.dealextreme.com/details.dx/sku.35475
http://www.dealextreme.com/details.dx/sku.11880
http://www.dealextreme.com/details.dx/sku.11896 (this one is big 6.3")
http://www.dealextreme.com/details.dx/sku.2834

More expensive but much larger and "nicer" for a larger version of this table?
http://www.rinovelty.com/index.cfm/fuseaction/products.detail/item/AMCOMPA/18pc_bulk_compass_set

18 of them for $26 just rip the compass itself out.

These are one of my favorites more money ($1 a pop but also much larger at 2")
http://cgi.ebay.com/60X-New-Plastic-Compass-Key-Rings-Wholesale-/380302127478?pt=LH_DefaultDomain_15&hash=item588bc5f176

best deal (same ones used here)

http://cgi.ebay.com/Wholesale-Lot-20mm-Small-Mini-Compasses-4-survival-kit-/130461497769?pt=LH_DefaultDomain_0&hash=item1e601c79a9

48 for $15 so 500 would cost about $165 you might be able to wheel and deal a better price ordering that many though.

author
feistydonut (author)nerys2011-01-19

144 for $8  on Oriental Trading

author
saronpaz (author)2010-12-30

you might find your project in a bit wider perspective in dunne & rabys placebo project from 2001 which includes amongst others a compass table.

compass3.jpg
author
Jakeg (author)2010-12-30

I would love to do this project... But unfortunately I dont have the time (or patience) to do it... =(

author
Darwinfish (author)2010-11-27

That's really cool. Just when I thought I couldn't get any more lost... XD

author
Bitkid (author)2010-10-23

So all together how much total money was used to make this project?

author
Exocetid (author)2010-09-02

Not what i thought it was, but still clever! Being old and feeble, I thought it was a table where the top was a compass and pointed North via the coasters. Not as much fun as Noah's table, but just one compass instead of a gazillion--that is how many compasses are needed for this, isn't it?

author
woodstockbirdy (author)2010-07-02

how much did all those cumpases cost???

author
Ssslouter (author)woodstockbirdy2010-08-27

do the math 1 for 20c, he need 500, 500x0.2 or 1/5 of 500 is 100. it cost somewhere around 100 bucks.

author
woodstockbirdy (author)Ssslouter2010-08-27

ouch thats really expensiv for a table

author
mimekiller17 (author)2010-04-16

 lol awesome video, i bet he ALWAYS knows were hes going :) awesome                      North East South West = Never Eat Soggy Waffles, but thanks to ur post, i can eat soggy waffles and STILL KNOW WHERE IM GOING!!! isnt that AWESOME?!?!!?

author
kfr1sby (author)mimekiller172010-04-19

North, East, South, West
Never eat shredded wheat.
Our teacher taught us that in school, and I still use it to this day lol.

author

NEWS stands for north, east, west, south .

author
teamcoltra (author)kfr1sby2010-05-03

Never Eat Sour Worms

author
bmlbytes (author)teamcoltra2010-06-08

Our teacher taught us Never Eat Slimy Worms

author
xojess (author)2010-06-20

Oriental trading company sells those little compasses for $7.95 for 144! http://www.orientaltrading.com/ui/browse/processRequest.do?demandPrefix=12&sku=39/37&mode=Searching&erec=2&D=compasses&Ntt=compasses&Ntk=all&Dx=mode%2bmatchallpartial&Ntx=mode%2bmatchallpartial&N=0&requestURI=processProductsCatalog&sd=Mini+Compasses

author
fkuk (author)2010-04-19

how did you mesure the table to that when you put in the magnets they lined up perfectly with out leaving gaps

author
bmlbytes (author)fkuk2010-06-08

You could just measure the diameter of one compass, and make sure the table has a multiple of that diameter.

author
CamWaite (author)2010-05-31

 i vote you mount large magnets in the coasters!

author
Derin (author)2010-03-12

Now make the whole table a single big compass. LOL Good work.

author
noahw (author)Derin2010-03-12

That would be pretty sweet. 

I wonder what the limiting factor is on a giant compass. 

The friction on the rotation point, the strength of the earth's magnetic pull, the weight of the needle itself? 

Anyone have any experience with very large scale compasses?

author
Kiteman (author)noahw2010-04-15

The big limiter is friction - even the compasses you used are balanced on a pin-point (if the table ever gets a big whack, some will come off their pins - be careful).

You could try the ancient floating-needle trick - make a huge compass rose on a sheet of light foam, float it on a pool under a sheet of glass.

At the N & S points of the rose, inset magnets arranged to act as the ends of a bar-magnet.

What would be the point, though?  Once you place the table, it will turn, settle, and never move again.

Instead, I would randomly set neodymium magnets into the sheet of foam, with randomly-facing poles (you can get cubic magnets), so that the foam disc with twitch and turn as magnetic objects are placed on the surface.

author
curtismartz (author)Kiteman2010-05-05

 the foam would be drawn to one side of the pool and not rotate, ok last comment here. I made a few little mistakes in the descriptions of the huge compasses i have made, the best giant compasses I have made used rare earth disc magnets aligned along the north south axis, they were balanced and hung by a filament, the simplest of which consisted of a single 2" diameter 1" thick neodymium iron boron disk attached to a fine thread with electrical tape and hung from the ceiling, I have used smaller safer : ) disks stuck in the ends of a length of rigid tubing and suspended similarly, various configurations and materials all definitely did some strange things besides aligning themselves north/ south, the strongest were perturbed by passing cars and most of the others responded in unison even when separated a great distance e.g. 40 feet or more, to periodic oscillations that, I have no concrete explanation for but, I think may have something to do with the field produced by the electrical system in the house .  

author
Kiteman (author)2010-05-04

The compasses being used are not "outdoors" compasses, they are plotting compasses, used in schools to show the magnetic fields around bar magnets and similar.  We go through loads every year as pupils drop them and the needles come off the pins.

As for your idea, spreading the magnets out like that will diffuse the poles of the overall field - you'd be much better off lining them all up across the diameter of the disc, all pointing the same way.

About This Instructable

137,090views

616favorites

License:

Bio: I've worked for Instructables off and on since 2006 building and documenting just about everything I enjoy doing. I am now the Creative Programs ... More »
More by noahw:How to Send Art Into Outer SpaceCómo soldar意式烤面包食谱
Add instructable to: