July 21, 2008

Measuring for the Trays of a Clamshell Box Based on your Materials

Sophia Siobhan Wolohan Bogle
Ashland, Oregon

Getting Started: So, at this point you have measured your book as per my previous instructions. All of those measurements are necessary for creating the small tray. You always make the small tray first. In fact, you could make the small tray and cover it and then measure for the bigger tray, but I will give you the way I do it which is to measure and cut out both and then assemble them. This way has more room for error of course, but if you pay attention it should come out fine and is faster in the long run.

I should mention here that I am doing all my cutting on a board shear. I have yet to cut out a box without one. So if you don’t have a board shear just be sure to do what you have to do to be accurate, like taping down your flat straightedge and cutting off your mark entirely instead of halfway into it.

Wrapper: Before we start on the first tray there is another aspect of measuring to consider. One way to protect the book (or fill up space) is to create a paper wrapper like the one in the picture. This is useful if you have a book that is falling apart and you don’t want to lose any pieces or if it is not a book, but a sheaf of loose pages. If it is necessary to make a wrapper, be sure to account for the extra thicknesses in your measurements of the original book. In other words, make the wrapper and then do your measuring.

To Line or not to Line? Another way to protect your book is to create a soft liner in the trays. The book really does need to be supported fully in the box with no wiggle room. If it is allowed movement, then damage will occur. You can take some of the guess work out of measuring by using felt or something squishy to line the trays with (obviously something archival is preferred). This does make it easier but you still have to be accurate. It is possible to be accurate enough in your measurement that you do not need the squishy material. I have only used it a few times for an effect and one time I used it when I poorly measured a book and didn’t want to re-make the tray. Fortunately the tray was bigger. Had it been smaller I would have had to start over. I used unbleached wool batting that I got from a fabric store as the liner. To apply it, I glued the surface it would be attached to and didn’t attach the wool felt until the glue was getting tacky. Double sided tape would work too. The point of this is that you don’t want the glue to find its way through the felt. You can add the measurement of the Liner in with the other materials but because of the squish you will want to cut the measurement in half. Find something that is half as thick as the felt like 2 chipboard glued together and use that to stand in for the liner.

Parts to Small Tray: There are two trays to be made for a clamshell box. The most important one is the smaller one because that is where your book will rest. There are four or five parts to the bottom tray. Four of them are obvious; the bottom and the three sides. The fifth is the spine support piece. This piece will not be attached to the bottom tray and is instead attached to the spine of the case. It must be taken into account here though because when the box is closed this piece slides into place as a forth side to the small tray. This piece is optional and many clamshells are made without it, but it provides another measure of protection for the book and I prefer the way it looks. (see picture)

Gather Materials: You will need to gather together small pieces or strips (about 1/2 -1 inch by about 2-3 inches) of both your covering material and the board you will be using to make the box. Also the squishy liner if you so choose.


Covering Cloth

Liner (Optional)

Next you will need some pieces of chipboard or something similar. It makes it easier if all these pieces are the same size, but they don’t have to be. We are going to use the chipboard to stand in for the book-cloth and liner as well as some space. If the chipboard is just about the same thickness as two of your book-cloth strips it makes it easier to measure because you can substitute the chip for the cloth. Because the chipboard is stiff it is easier to hold it up to make a mark on your board.

The Theory: What we are doing is running a tally of all the materials involved in each dimension of the tray. So for the height of the tray we have the # (measurement of the actual book height) + we have the two boards that will be on either side of it + the four thicknesses of book-cloth. If you wanted to you could substitute something for the four pieces of bookcloth. It just has to be at least as thick as the four pieces plus it could be slightly thicker for a bit of space.

Turn-Ins: It is also good to remember that the turn-ins add extra thicknesses. This doesn’t matter for books much because where the turn-ins are is usually where the book has a dip or curve. Books, after all, are not usually perfectly square. But keep it in mind and make adjustments as necessary.

The Visual: Imagine a straight line cutting a cross section of each direction of the tray when it is assembled. Then you just add up all the materials involved. (See Cheat Sheet)

Note on Materials: I prefer to use Canapetta, an Italian linen paper-backed book-cloth to cover the trays. It has a tooth to it and is fairly forgiving in general of glue marks unlike silk. Also I find it will stretch a bit to help get it around awkward corners. I have even covered raised bands with it.

Advice: Try making one tray completely with the materials you want to use and see how the book fits. Every time you change materials there is room for error so find something you like and stick with it. (within reason of course)

Sequence of Cuts: Have the Cheat Sheet nearby. Have all your pieces of materials and measurements. Begin with board that is square to two edges at least. The grain should line up with the grain of the book as it will sit in the tray except the Head and Tail Side pieces which just follow along with fore-edge piece so they are all the same.

You will be cutting out five pieces of board with several cuts:
  • Start with the Height measurement. Follow the Cheat Sheet. Just line up all the pieces along with the measurement and set your gauge to make a square cut. Make sure you have enough length of this first piece to also cut at least one Thickness measurement as well but preferably four Thickness measurements.

  • Take that piece that is now accurate on three sides and cut the Width of it. This will be your Small Tray Base.

  • Next cut four Thicknesses all the same from the “leftover” board you just cut to the right height. This gives you the Fore-edge Side which is the same height as the Small Tray Base. It also gives you the beginning of the Spine Support Piece, as well as the beginning of the two other Side pieces.

  • To get the right height for the Head and Tail Side pieces you have to take the width of the Small Tray Base and subtract one regular board thickness from it. Use the board itself instead of trying to get ruler measurements. Make the cut for both Head and Tail Side pieces.

  • This only leaves the Spine Support Piece. Mark this as such and set it aside until the box is covered. Then figure out how much to trim off so that it will fit in the space left when it is covered in paper or whatever you will be lining the box with.

Large Tray: There are only a couple of differences for cutting out the Large Tray. You already have pieces cut that you can use as measurements and you will not need to cut the fourth thickness as there is only one Spine Support Piece. Otherwise, just follow the Cheat Sheet and the Sequence of Cuts.

Cheat Sheet:

Small Tray Measurements:

(# = measurement of book)

(chip = chipboard - Remember that the chipboard should be about two thicknesses of your cloth.)

Height: # + 2 boards + 2 chip (or whatever you made that equals four book-cloth plus some space)

Width: # + 2 boards + 2 chip (same as above)

Thickness: # + 1 chip (The chip here is for whatever liner you will use plus space because the book-cloth will be under the book as well as covering the top of the surrounding boards so they cancel each other out.) I usually just use a thin paper like Dove Gray. If you were going to use felt of something else thick you would use something thicker than one chipboard to represent that added thickness.

When you are done you will have the following pieces:

  1. Small Tray Base
  2. Fore-edge Side
  3. Head Side
  4. Tail Side
  5. Spine Support Piece

Large Tray Measurements:

BEFORE assembling the small tray!

Use the small tray boards to measure for the large tray right on the board shear or other cutting surface.

Height: Add 2 boards and 3 chip + 1 cloth

Width: Add 1 board and 2 chip

Thickness: Add 1 board and 1 ½ chip (or rather 1 chip and 1 cloth)

If the small tray is already assembled then use these measurements:

Take the small tray’s measurements and add the following additions to them.

Height: 2 board and 3 chip

Width: 1 board and 2 chip

Thickness: 1 ½ chip

If anyone actually tries to make trays based on these instructions please let me know if they are clear and where they need improvement. This is the first time I have tried to write it all out and it is hard to follow my own directions when I already know what to do. Feedback will be helpful and appreciated. Thank you.

Sophia Siobhan Wolohan Bogle
Red Branch Book Restoration

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