This bookbinding press combines many functions into single, compact device. My aim was to make something that doesn't take too much space to store, but is sturdy and useful.

Most DIY bookbinding press designs consist of two plywood sheets and four threaded rods. This is simple to make and likely works well, though I expect it is somewhat slow to use because of the four screws with low pitch. Fancier versions usually have one central screw, often with a trapezoidal thread. Sometimes separate plywood boards are placed in between the press for specific tasks, such as forming the book back.

I wanted my design to be low profile for easy storage, preferrably so that other stuff can be stacked on top of it. I also felt that there is no reason not to integrate other functionality, such as hole punch guide, in the same device.

Design

I've wanted to make wooden threads for a while now, and this was an excellent opportunity. I made a split thread design, where the clamps engage with side threads but permit free movement in their fully open position. This allows quickly moving the pressing board to the correct height and then tightening to press it down. Split threads do not provide lateral positioning, so a vertical brass strip is added to keep the boards aligned.

Choice of the thread pitch is a compromise between wood strength and adjustment range. I estimated that 10 mm thread pitch would be reasonably strong. To allow positioning the platform at any height, I needed the thread to move by 15 mm within the 90° rotation of the clamp. That way there are always two possible thread positions for any book thickness. I calculated that with typical human hand grip strength, the clamps would provide 50 kg of compression each.

One edge of the boards contains pockets where a long brass strip can be inserted for pressing the shoulder ("french groove") in the spine of the book. The top board also has holes every 10 mm to act as a guide when punching holes for sewing thread.

On the opposite edge, the bottom board extends further than the top board. This side is useful for trimming page edges with a knife, where the bottom board provides support for the pages being cut. The side rails are square and the press can be oriented vertically for working on the spine of the book.

Build

Material choices:

• Top board: 15 mm birch plywood, with 25 mm birch edge strips
• Bottom board: 30 mm birch plywood (two 15 mm sheets glued together)
• End rails: birch
• Clamps: unknown hardwood, chosen for strength and darker color

I cut the threads on a CNC router, using 2 mm endmill. Some sanding was needed afterwards to smooth them out. The design is oriented so that wood grain supports the threads well. The end rails of the bottom board are further supported by long screws driven in from the bottom, which reinforce it against the vertical pull force.

Rest of the build is basic woodworking.

I applied edge strips to all plywood edges for aesthetics, though some of them also add to the strength of the build. The 30 mm bottom board is probably overkill, but I calculated that with 200 kg of total compression a single 15 mm plywood sheet would deflect by almost a millimeter. The top board has extra support provided by the edge rails. For reduced weight, it would have been possible to put wider edge rails on the bottom board and leave the bottom hollow, but on the other hand the weight provides stability in use.

All surfaces were finished with a beeswax and paraffin oil mix. This provides some protection against glue sticking to it, while being durable against wear on the sliding surfaces. I had calculated that the screw pitch would result in a self-locking thread, but I neglected to consider how much a wax finish would reduce the friction. To fix this, I hid some sandpaper under each clamp, which provides friction proportional to the clamping force. Small magnets help hold the clamps fully open when lifting the board.

To accompany the press, I made a small toolbox for various bookbinding tools. The knife is made of an old hand saw and sharpened so that one side is flat, to cut flush to the edge. The awl is made of a bicycle spoke.

Results

The end result feels very sturdy. The hole punch and trimming functions in particular work very well.

The clamps are a bit cumbersome to get started, as you need to get all four clamps started on the thread before you can start tightening them. It's probably still faster to do than screwing down 4 regular nuts would be. The maximum book thickness is limited to about 4 cm. Making the end rails taller would extend this height.

I don't have a scale suitable for measuring the clamping force. I made an attempt to estimate it by measuring the pressure in a bicycle inner tube, which gave 0.6 bar pressure for 1 meter × 4 cm contact area. This puts the force at about the same as my design calculations, around 200 kg.

I made this as a gift to my wife. She binds her own watercolor sketch books to have a wider choice of paper type used. Apparently it is also significantly cheaper to buy the paper in bulk instead of prebound books. Her initial comments of the press have been positive, which I have to trust as I have zero bookbinding experience myself :)

The FreeCAD / Ondsel design file is available here. It has the basic design correct, but some dimensions and details may be a bit off, as I didn't really look at the drawings that much when building.