I'm having a "challenge" in my geometry classes getting students to use rulers as measuring devices in constructions instead of just using them to connect points with line segments and extending line segments. It's very understandable when they use them to mark off a line segment congruent to a given line segment. But then they extend the idea to a sort of "guess and check" when they really should be using a compass instead. At the same time, I don't want to criticize their ingenuity or suggest that tools shouldn't be used as fully as possible to solve problems when appropriate.

So what I'm learning towards now is having 25 or so unmarked straightedges to have students use, so they are constrained to using them as Euclid intended. I haven't ever seen them sold as such, so I'm wondering if people have any suggestions about common "blank ruler-like" products that could be used as substitutes. (I would like to have an actual product for them to use, and not, say, using the edge of another textbook or an sharpened pencil or something like that.) Alternatively, I might get something like a simple piece of moulding cut into foot-long segments and sanded down.

Does anyone have any experience or suggestions along these lines?

For instance, here's an example of a brilliant but illegal construction I'd like to avoid seeing:

Here, we bisect $\angle BAC$ by swinging an arc with $A$ at the center that intersects the angle at $D$ and $E$. Then, using the ruler to measure $DE$, construct $F$ as the midpoint. Then $\overline{AF}$ is our angle bisector.

ETA: I visited my local craft store and found 10" craft sticks in a pack of 50 for $7. The edges are rounded like popsicle sticks, but they're long enough that students will be able to draw any line segments they want with just the straight part. I think this is going to work really well for me. Thanks to everyone for the suggestions!