Great thanks to Martin Schneider for his nice design.
see https://www.thingiverse.com/make:842468
and https://openpressproject.com/
Nevertheless I found something to improve ;-) and therefore did a complete redesign.
Although the interface dimensions are identical the parts may be not compatible.
So what did I modify:
More stiff connection between the side parts, on the top with an M4 screw, on the bottom with the special designed label plate that acts simutaneously as clamp and pulls both side parts together.
Square shaft for the lower roller made of two halfs, each with a slight step on one side which fits into a pocket on the lower roller and the handle arm. The square shaft half parts are sitting quite strong by purpose. Be aware to fit the slightly elevated ends, one in the foreseen pocket of one lower roller, the other on the opposite side on the handle arm! Fixation is done by M4 countersink screws on either side.
I didn't like the original straight handle. In my opinion the design of the straight handle did not fit to the curved design of the side parts which are looking a bit like those old manual printing presses. So I did a design with a curved handle arm and a nice handle as it can be found on old lathing machines too.
I redesigned the sliding shape and form of the slides which guide the upper roller in the side parts. The grooves in the slide and slides could be used whether for greasing or for putting some balls in and upgrade it as ball bearing. I just used it for grease but one could upgrade it to a roller bearing too.
The upper roller was redesigned and the grooves for the ball bearing/greasing was integrated. Also some chamfers were added to make it better printable without support.
I redesigned the lower roller with the pocked for the square shaft and the new gear teeth. The printing table was therefore also redesigned.
I used PLA with 0.2mm layer thickness. All parameters should be visible in the 3mf-file.
The square shaft half parts are sitting quite strong by purpose. Use sandpaper if it is too tight for your print
Be aware to fit the slightly elevated end of each alf of the square shaft in the foreseen pockets - one side in the lower roller and the other in the arm of the handle!
See https://openpressproject.com/blogs/news/how-to-3d-print-your-own-printing-press for more tips.
Here are the standard parts used in the design:
The author remixed this model.