As far as we could make it out of the plans, in case of smaller books we lose most of the pixels not pointing right in the center of the target pages however. If you fasten a camera on the cross member between the front and back plate it will point around 8-1/4" which is the standard width of an A4 paper sheet. So, if you want to scan books of A5 size or any smaller books than A4, as we understood, you lose loads of pixels getting lot worse quality.
As our cameras are far from 600 dpi it is really important to keep at least the quality that we already have. So to that, we wanted to make the camera movable on the third axis -- mostly up and down -- and we made some changes to the 1.0 March 1 plans that we will use in our built soon. To see them, you can take a look at the plans below!
In brief, we both made it possible to center the camera to around 4-1/8" of the width of your page to be scanned and move it genuinely beyond these limits. What it means: we can make the best out of our cameras with this upgrade; we get twice as much in DPI, which means we get 4 times more pixels of the same page most of the times, as books more tend to be around A5 than A4.
However, they are not yet tested, so we can't guarantee they work. However, this upgrade should be easy to apply to the standard book scanner unless you cut out already your front and back plate, and you have no wood to cut new ones out.
If you have any ideas or suggestions, feel free to let us know!
Pictures are coming as soon as we're done with the cuts and the assembly!
As the pictures are not professional plans like those you find for the assembly done with CAD, it may be useful to get guided through the process in detail.
Step 0.
Cut a cubic hole in all the cross members' tongue making them equally wide, as below. The length shall be the width of the plywood or other wood sheet you use.
Step 1.
If done, make a hole on both sides of the cross members that is big enough for a wing nut's head and wings if put in sidewards.
If you don't have a CNC machine it's easy to do by drilling through three times making a T-like shape that you can cut together with a jigsaw -- you can see this on the plans below, too. After that you've got to chisel the part where the wing nut will lay upon.
Drill two wholes across the small member untill you reach the T-shape holes you just cut.
Step 2.
Here, for sure, you may guess that it's quite dumb to use a threaded rod instead of leave the work for a threaded bolt on the other side, but usually you can't get the 12" (~30cm) long threaded rod that you need for the lifting lever but bigger. As it is one of the main ideas of this forum to make a scanner with a great prize/value ratio, keeping the builds' prizes on an affordable level and making a scanner which can be a competitor of those you find on the market for the same prize, we decided to use the rest of the threaded rod cutting them the proper size saving a tiny bit, but still making efforts not to let the prize rise higher.
So, you can, of course, buy threaded rods of the same size but you can use your threaded rod paid already.
Step 3.
After you put your wing nuts sideways in the cross member you need to modify the front and back plates -- this is going to be the harder part.
Still, if you don't have a CNC and can't or won't get it cut by one of them, you can find these tips useful.
As you must have noticed it, the camera supporter cross member is in parallel with the glass platen so that you can get close rectangular shots of your books and avoid best trapezoid shapes. It means, if you want to center your camera to a smaller book you'd better move it along with the cross member -- this is what we are about to do!
Now than, you need to prepare the cross member slots of the front and back plates creating a track to move the cross member on it based on the the March 1 plans. First, before any cuts, you need to drill two mortise to cut the long rounded slots. If you're done, you can go for the two bigger cubic slots. Here, you need to cut up until you reach the line of the cut you find in the March 1 plans here. To make the proper cuts you have to make parallel cuts to the opposite glass platen -- all marked with red. You DON'T connect the two new cut lines but leave a tongue that you just drilled and cut in the middle to function as a slot for the cross member. Before putting them together they're supposed to be trimmed; the edges may rub in the slots so it should slide easier that way.
If you got the slots to slide the camera supporters on, before you do the last thing you've either got to bolt your wing nuts on your threaded rod that hangs out of your front and back plate, or put through and bolt your wing bolts in the wing nuts you had in the cross members.
Now you can start moving your camera on the third axis and enjoy better scan quality!
