> I recommend printing the gears with an ink jet printer. Even cheap ink jet printers print very scale accurate but Not all laser printers are accurate.
Does anybody know whether that's still the case, and why?
Laser printers project the image onto a drum using a laser and a spinning mirror. There can easily be issues with the scale accuracy. Ink jet printers conventionally move the head along a linear rail with a timing belt and stepper or servo motors; that better guarantees the precision as the pully diameter and step size or encoder resolution are the items determining precision.
The light source isn’t that much of an issue the problem is that you are projecting on a curved surface (even tho you are projecting a line at the time) and at an angle.
Basically photolithographic printers can have the same issues as you have with projectors where the image can be skewed or morphed so if you are printing say a square you might not get 4 90 degree corners or perfectly straight lines, the size of the print can also vary depending on the distance between the projector and the drum if it’s not exactly the same as the printer thinks it is the size will change and it varies it would cause perspective shift skewing.
With ink jet alignment errors would maintain the shape and size but the shape might not be aligned perfectly to the page so your errors would only be positional or rotational with photolithography you have perspective and projection transformation errors.
Photolithography printers for engineering/architecture have builtin auto alignment to correct for this.
While the errors even for most home printers are very small if you print something like a gear it’s enough to cause wobbling and fit issues.
That said for wood gears if you cut them by hand I would imagine the tolerance errors from cutting would be worse than from printing unless you are very skilled.
Good point. The LEDs lighting would eliminate horizontal distortion, and if it's a color laser prointer, the vertical scaling has to be just right too or the colors won't register.
According to Matthias, this is because inkjet printers require accuracy since print heads for black and different colors, or even each color are spaced differently.
So for the alignment to stick (anyone else remember when you had to manually align inkjets?) they have to move very consistently across the page.
> I recommend printing the gears with an ink jet printer. Even cheap ink jet printers print very scale accurate but Not all laser printers are accurate.
Does anybody know whether that's still the case, and why?