aagh, I edited this on the instructables mobile app and its deleted the intro page, I'll sort it out when I get a chance later on..
photos and sketchup model here for now
Step 1: Get Wood
Get your pieces of wood cut ready, I'm using 4mm plywood which will give a final thickness of 16mm for the heart when assembled, I figure that's a nice size not too big but not so small it gets fiddly.
Cut 4 pieces, I then used a block plane to get them the same width, but this really isn't necessary as your going to be sanding them to size later anyway, so don't bother.
Step 2: Get Into Shape
Mark out the shape, using a ruler measure two points 40mm apart and mark them, then connect them diagonally as shown, then using your compass set to 15mm diameter draw a semi-circle from the centre of one of the marks to make the basic shape. Carefully saw the shape out and sand to the line if necessary.
Then you can use this first shape as a template to make the others, you will need 8 in total, mark them out but don't cut them out yet.
Step 3: Make Pivot Holes
Before cutting them out mark the holes for where the pivot will go to open the heart, the pivot will need to be two halves which combine when the locket is in the heart shape in a way which allows the top to rotate away revealing the photos.
My initial idea on how to do this was to use semi circles of wood cut out with plug cutters on the drill, the bottom one 15mm and the pivoting one smaller, unfortunately the smaller piece was just too small to handle and didn't provide enough glueing surface to make a satisfactorily strong connection.
The solution I tried next was driving a nail through the top pieces and into the larger semi-circles, then cutting the nails to size with the cut off wheel on the dremel, but this also didn't work well as the top now had a nail head showing, which looked rubbish, and the two top pieces wanted to rotate around the nails rather than as one piece.
Step 4: A Lathe Would Be So Useful..
The method I came up with in the end was to use some 15mm dowel rod, cut to size I could somehow thin it in the middle where the smaller semi circles would have gone, and then somehow rout out a couple of millimetres from the top pieces to glue it to giving a solid pivot piece and a nice big glueing surface (its end grain but we cant really complain it'll still glue well enough for what we want, I hope)
I marked out where I wanted to thin out the pivot, and set about it, using a saw, sanding, various attachments on the dremel, nothing seemed to be particularly effective or precise. Then I had a brainwave, I could use my drill as a lathe! this kind of worked, but it didn't feel particularly clever or safe, and I don't recommend it. For a start my drill is a normal drill in a drill press stand, which is kind of wobbly and not great in the first place, so now I have a drill pretending to be a drill press pretending to be a lathe, and I've never used a lathe nor do I have much idea how to use one. Anyway it got the job done this time.
Then sawed carefully the piece into two halves, obviously the two halves will not be exact semi-circles as they will be missign the part the kerf of the saw took away, the correct way to deal with this might be to make two pivots and saw along the line on both to make two exact semi-circles but it took me too long to make just one so I'll have to make do.
I was rushing. take your time and do it better. :)
Step 5: Make It Fit
using the dremel with the sanding disc attachment to get the pivoting pieces to the exact size needed.
I then used the sanding disc to rout out the space in the top pieces to accept the top of the pivots, there is probably some easier ways to do this but I couldn't think of any at the time (rushing).
When I was happy with the fit, I glued up the pivots and waited for the glue to dry...
Step 6: Show Your Face
At this Point you will want to drill the holes for the photos to show through if you didn't do it earlier, print out your photos and cut them to size. I used GIMP to prepare the photos to the correct size
Step 7: Magnets!
I used magnets which will hold the finished item firmly in place when it's in both its oblong shape and it's heart shape, also they hold the to moving pieces together to help them rotate easier.
I used 4x neodymium cylinder magnets 2mm diameter x 8mm long, which gives a nice firm hold but still allows the halves to rotate smoothly. Drilled the small holes for them and dipped a little super glue on them before pushing them into place.
With the magnets in place I set about making the main pivot for the two halves of the object, I decided to use a nail for this, put one end in the vice and bent it into an L shape, then carved the shape into the middle pieces on one half of the object, and carved the shape of the nail and head into the other. I'm sure I took photos of these steps but seem to have lost them (probably again as I was rushing).
With that done I put the L shaped part of the nail in place and glued up that side of the object with wood glue and waited for it to dry a bit.
Step 8: Shape Up
once the glue was dried on that half I glued up the other half in place over the nail head and clamped the whole thing in the vice for the glue to fully set.
Once set, I set about sanding the shape up more evenly, checking it in both shapes.
I also intended to chamfer or round over the edges but didn't have time, I intend to sneak it away again to finish the edges off more tidily at a later time.
I then added a little danish oil to make it look a little more finished.
Step 9: Done -ish
And Finished, just on time for valentines (sort of, I finished it on valentines morning)
But not quite, as you can see in the photos it's not perfect, some of the edges need tiding up, as well as the centre to take out those gaps, also I still think it needs more rounding on the edges to make it more finished looking, and more polished.
I will hopefully be updating this when I am happy with it with some more photos of it, but who knows when that will be, maybe in time for mothers day?!
Step 10: Update
since making this I've improved the heart a bit, by adding another layer of plywood on the top and bottom making the moving parts on the top a bit heavier and less flimsy feeling, it also stops them falling out as easily when the heart is half rotated.
I also rounded off all the edges on a powered sander which makes it look much more finished and feels better in the hand.
It could still be done a lot better though, and it's something I intend to have another bash at someday and make a better job of it, the parts need to be made much more precisely to get a more positive movement with no play or looseness.
themortalphoenix made it!