Size will depend on linen count. Stitch count is 82 x 32.
I used 28 count (or something close) and finished size of the keep was 2 1/2" x 5 1/2".
You will need - -
4 pieces of mat board or very stiff mounting board cut to size
approximately 2' of ribbon
heavyweight thin fleece such as Thermolam ( found with the interfacings)
fabric glue (or your choice)
fabric for outside and inside
self stick magnetic tape
Keep in mind that this is NOT a neat and well planned project! I used to make these many many years ago for the shop, mostly smaller with just a fancy initial. This is what I remember, and I didn't measure, accurately cut, trim, or care! So please excuse the messy photos!
Start by mounting your needlework to the mounting board by folding over and gluing on the back. Check Vonna's blog for clear mounting instructions.
You can add the fleece under your needlework for the top of the keep. Fleece should be used on the two interior pieces, but not necessary for the outside bottom piece.
Let the top and bottom outsides dry for a while. Glue a layer of fleece to one side of the two remaining mounting boards and then fold the interior fabric over and glue to the back, as you did for the outside pieces. Interior fabric can be coordinating or the same.
If you prefer to attach the strip directly to the fabric instead of the ribbon, that's another way. You can lay the ribbon over to cover and glue to back, or have the strip exposed and run the ribbon the opposite way to cover the ends. If you don't cover the strip, do not add another strip to the top or the two will stick together when closed.
Now you can start constructing the keep. Lay the outside bottom piece, glue side up. Cut two 4" lengths of ribbon and glue 1" to the bottom piece vertically, leaving the 3" free. Add glue to the entire piece (but not too close to the edge), and add the bottom's interior piece, wrong sides together.
You can see how much glue I use in this photo. I use Liquid Stitch because it grabs quickly and dries clear. I really push the fabric into it until I see the white oozing through the weave, then I know it will stay. I did mitered corners on the fabrics and I used the plastic handles of a pair of scissors to press the tacky fabric down and smooth it out. I try not to use my fingers since I would end up with glue everywhere.