Summary

A bread knife with an exchangeable, parametric blade.
As it seems, it also cuts fingers. Now I'm bleeding :-/

Instructions

BUILDING:

Just use the included STL files. You'll need:

1 x grip
1 x blade fixture (three sizes provided)
1 x blade (four provided)
1 x (3x16)mm screw
1 x 3mm nut

The blade fixture comes in three sizes.
Start with size "M" ("BreadKnife_BladeFixM_V10.stl"), it will fit in most (tm) cases.
The "S" variant is a little smaller, for fat printing machines and the "X" type a little larger, for precision freaks.

The blade should be printed with a layer height of 0.1mm or less, preferably on a glass surface. The tang might require some deburring on the bottom side.

Notice that the blade fixure is not symmetric!
The bottom is slightly inclined to match the shape of the blade.

MODIFYING:

If you own Rhino 3D, you can customize your own blade with the included Grasshopper script.
Please see "BreadKnife3.png" for an example on how to place the tip and fixture (tang) curves.
The knife geometry will be extended at x=0.

The hole in the grip (and the tang) is at x=-15mm, measured from the front.

As of now, the shape of the tang directly depends on the geometry of the blade, hence changing any of the parameters will require an optical comparison with a "baked" original or one of the provided STLs.

Default, working parameters:

blade width 25mm
thickness blade back: 3mm
thickness blade front: 1mm
tang 15mm, centered

Remember to align the blade with the xy plane.
Simply rotate it in the right view and lay it flat.

Good luck.
Oh - and watch your fingers :-/

Bread Knife