Making a Clamshell Box

The main difference with the clamshell is that you create two three-walledtrays, one of which sits inside the other. The process for creating the trays is exactly the same in terms of how to measure and cut and glue together. There are some changes in the measurements where you add cloth thicknesses in and a dust strip in the case of the base, but the basic procedure is the same.

So for this, I began by using the book I was enclosing to measure the base. The base is then used to determine the measurements for the dust strip and the covering tray. The covering tray is used to determine the measurements for the case.

What’s really different is covering the trays. There are additional cuts that need to be made to the cloth because it is a three-walled tray. Like the four-walled tray, I made the angled cut on the longer walls, but in this case, the spine wall is open. So the angled cut is actually made to both sides of the corner, giving a mirror image.

The next cuts are made at the top of the head and tail walls. You basically cut a straight line extending the edge of the board in each direction, but leaving about one board thickness. This is then where you make an angled cut.

This tray is then glued starting at the spine edge, then head and tail, and finally the fore-edge. Those extra cuts make sure that all of the corners are properly covered. At this point, we test fit our books to make sure that they fit. If not, it was time to start over. I made this box for one of the books that I completed in Bookbinding II, and I was happy to note it fit!

I’m afraid that I was rather lacking in the photo taking department for this box. But, these should give a basic idea of how it differs from the other boxes.  Anyway, after making the base, it’s used to measure for the cover. Once the cover is covered in cloth, that needs to be test fit over the base. Again, it was a nice fit. Making this box was like a dream. I couldn’t believe it.

Anyway, at this point, the cover is used to measure for the case. The case is cut and covered exactly the same way I did for the previous box. One thing I should point out is that mixture (PVC/methyl cellulose) was used exclusively in gluing the cloth to the boards. The main difference with this box is that scrap cloth is used to fill in the inside of the case as well as the outside baseboard of both trays.

The trays are then glued to the case using straight PVA. The larger tray is glued in first. This is done by centering it on the cover and making sure that the spine edges were flush. The hard part of this was that after the tray is glued in, we needed to have boards that fit the tray exactly and exceeded its depth. This was so that we could put it into the press. After it had pressed for at least 20 minutes, the smaller tray could also be glued in. For me, this meant creating a block from board cut especially to fit my tray. The book I was enclosing was so small that there weren’t any boards that fit the smaller tray/base.

The next step is applying the hinge. This too is done exactly the same as on the last box. Then lining paper is added. After that, it was time to add the dust strip.

The dust strip is a covered board that is added that fits inside the smaller tray creating an enclosed spine. This keeps the dust that always gathers on the top of everything, especially in my house, from getting to the book. I found this part to be fun. With the book in the smaller tray, I test fit several boards to figure out which weight board to use that would fit the tray snuggly. For my box, I used 80-pt board for the dust strip.

The strip is cut so that it is slightly shorter than the height of the tray and slightly smaller than the height of the walls. The dust strip is then covered with cloth. The fun part is adhering it to the spine. You can’t simply eyeball it because it has to fit inside the smaller tray. So, you glue the back with straight PVA and lay it cloth side down in the smaller tray. (Yes, I removed the book first. ) Then the spine of the case is folded up to meet the walls of the smaller tray and the dust strip is reversed onto the spine very carefully. Holding it in place, the spine is laid back down, so that the strip can be pressed into place. Yes, weights are applied.

Et viola, a finished clamshell.   I went with a plain cover.  An inset could have been added to the cover and that would actually be the last step.  I am really proud of this box and actually believe that I could make another. I think it fits my book beautifully.