This is a plane tool/scraper that can be adapted (via the OpenSCAD file) to use a wide variety of blades, blade (bed) angles, fixing methods…

This is intended to be used on soft materials or to remove small bits and blobs. The tool can get to cut well into hard materials (like PLA printed parts), but it's not as handy as a sturdy wood plane with a thick blade. As you may have guessed, I designed this for model kits, minis flattening top flat printed surfaces (aka, removing those small bits left at the finishing point of the print) and the such; but it doesn't have a good two-handed grip. In other words, this is not a heavy duty tool.

(I'm guessing that you may have guessed that already, but y'know, disclaimers and safety first!)

There are STLs included for several types of blades:

• The Amazon SEB, which stands for Single-Edged Blade. This is the kind of small blade found in many small scrapers and/or safety razors.
• The OLFA SKB-2, which is a longer trapezoidal blade used in small, cutter-like knives.
• The Stanley 1992, another trapezoidal blade, bigger than the OLFA, much like the ones used in the bigger scrapers (for windows, car vinyl removal, and heavier-duty than the plastic ones you'll likely be using when things get too stuck onto your PEI sheet).

Plus, I added a PDF to introduce you in using OpenSCAD customizable files, and the .JSON file with the presets for the STL. Drop the .JSON in the same folder as the .SCAD file to have all the presets available.

The OpenSCAD file allows for plenty of screw sizes, disposition and screw heads for holding. Just make sure that the screws you'll be using fit the blade —smaller blades like the SEB from Amazon/Aliexpress won't take comfortably anything bigger than a M2.5. In some cases, like the Stanley 1992, you'll have to screw them with a screwdriver from the back of the plane to fix them right, which is suboptimal. It's better to use a blade whose holes are separated enough to use cylinders with a nut trap —this way, you can adjust them finger-tight until the blade is straight, then finish tightening witht the screwdriver if needed.

Hint: Print the cylinders with nut traps adding a bit of fuzzy skin. This will help you get a better grip —sometimes these things are small.

There are (optional) alignment lines at the top of the blade bed to help you check a perfect alignment of the blade. You can also rest the plane flat on top of a raised surface (like a couple of paper sheets on a table), with the blade outside that surface (i.e., touching the table but not the paper sheets), and then tighten. That should leave the blade protruding just a bit from the plane, in case you want a good precision-ish approximation.

There are also optional texts to add to the side of the plane the bed angle. Note that this won't be the final attack angle of the blade, as this depends on both the bed angle and the blade edge angle. Wood plane blades have a true single edge (the Amazon SEB is actually double-edged in one side only), and thus the bed angle is the same as the attack angle, but hobby blades are mostly double-edged (edged on both faces of a side of the blade).

FWIW, a final attack angle of 37-ish degrees is considered as the “all-purpose rounder”, 45 degrees is a very coarse and hard angle, while 15 degrees gives a very smooth result. Think of sandpaper grits, but the other way around —the lower the number, the smoother the result. You won't be able to go lower than 15 degrees, though, and that with relatively “tall” blades; otherwise, there would be no way that the screws would fit, even using countersunk heads.