Introduction: Cardboard Bender
A tool is something that makes life easier and more convenient. I have got a rather huge mass of cardboard (a cause of a new furnishings :-)) and appropriate number of ideas to make something with it (Bag for Containers). One problem is bend operations. Cardboard plates have a multiply layer (as usual) so I get clumsy splits during bending. To prevent such behavior I decided to flatten cardboard according the bend line. At this moment we get situation for a ... NEW TOOL. How to make flattening along the path? Certainly, using a one of the ancient inventions – the Wheel. We need only move the wheel (roller) along the path on cardboard surface with giving insignificant pressure. This principle we use in home preservation to connect bank and cover (or let's remember about the roller-machine for road construction). Concept of a tool is very simple: roller (wheel) and handle – nothing more.
Step 1: Materials and Tools
Materials:
- 1 wooden slat (300x30x20 mm) for a Handle;
- 2 aluminum plates (150x20x1 mm) for a Bracket;
- 1 wooden cylinder (D45xH16) for a Roller;
- 1 screw M5x40;
- 2 screws M4x30;
- 1 spring washers M5;
- 2 spring washers M4;
- 3 plane washers M5 (D15);
- 3 plane washers M5 (D10);
- 2 hexagon nuts M5;
- 2 hexagon nuts M4.
Tools:
- screwdriver with a bit set;
- combination pliers;
- drill, hacksaw, rasp, file, sandpaper (to prepare parts).
Step 2: Parts Preparation
According to design drawing the "hand-made" parts are: the Roller, the Handle and two Brackets (link1 (google drive), link2 (yandex drive)). The main part is a Roller. You can make it from a wooden cylinder using a turning lathe (or hand rasp ;-)). Keep in mind that outside working surface of a Roller need to have appropriate width (no more then 4-5 mm) and shape (rounded edges). For a Brackets you can use appropriate aluminum or steel plates. I made these elements using a piece of standard aluminum angle profile by cutting it along the corner edge. The Handle is any wooden slat with appropriate geometry. What about screws, nuts, washers ... Certainly you can see the parts list in the design drawing and on Step 1. But perhaps you find analogical elements into your "home workshop". So, we have prepared all parts. Let's start assembling.
Attachments
Step 3: Assembly …
The base of assembly is a Roller axis.
Step 4: Assembly …
Put the first Bracket on the axis.
Step 5: Assembly …
Step 6: Assembly …
We will use two washers for each side of Roller as a slide bearings.
Step 7: Assembly …
Put the Roller on the axis.
Step 8: Assembly …
Put two washers on the other side of Roller.
Step 9: Assembly …
Step 10: Assembly …
Put the second Bracket on the axis.
Step 11: Assembly …
Put the additional washer on the outside surface of the second Bracket.
Step 12: Assembly …
We use only one nut until the final fixation.
Step 13: Assembly …
Put the Handle between Brackets.
Step 14: Assembly …
Put the first screw to fix Handle in Brackets.
Step 15: Assembly …
Use the spring washer to prevent auto disassembly.
Step 16: Assembly …
Put the fixing nut for a Handle.
Step 17: Assembly …
Make the same operations for the second mounting "screw-nut" subassembly on the Handle.
Step 18: Assembly …
Step 19: Assembly …
Step 20: Assembly …
Put spring washer on the Roller axis.
Step 21: Assembly …
Put the second fixing nut on the Roller axis.
Step 22: Finish
Test our new device in action.

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21 Comments
1 year ago
I took a different approach. A 3/4" hardwood board with one edge cut on a 45* angle is used to crush the cardboard on the bend line. Holding the sharp edge down on the bend line also helps with getting a crisp bend. Works across grain or with it.
Reply 1 year ago
Thanks for your advice - need to be try on my next job with cardboard
3 years ago
Made from 5mm acrylic, graphite powder lube...loving it already after using it just ones.
4 years ago
Thanks for all who are interest in this problem. Last weekend i made some experiments with a cardboard bender (result project: Cardboard Tool Bag (https://www.instructables.com/id/Cardboard-Tool-Bag/)). The thickness of cardboard was 4 mm. When I pressed hard on the fold line I got breakages (cuts) on a cardboard surface. But when i dosed force i received depression track and it became more easier to execute a bend. As I understand it the MAIN THING IS A ROLLER MATERIAL. When I tried to used roller made of a hockey puck (RUBBER) the results became stably good in comparison with wooden roller.
4 years ago
I do hope you let us know how your further experimentation goes!
I'm not an engineer so am not about to produce beautiful drawings like yours, but I've worked out my own solution to this problem over the years. I draw a line where the bend needs to be, and then carefully cut through only the outer layer of the corrugation on the outside of the bend. This works reasonably well against the grain, but of course it weakens the construction, and your method looks vastly superior. I'm sure I must have a suitable wheel around somewhere to make something like this that would work - thanks for the idea!
4 years ago
Very good idea and clever solution, not to mention a very very good 'ible!
I'm going to try making one using a wooden wheel from the craft/hobby store instead of trying to make it from a dowel.
4 years ago on Step 22
Very clever tool, great photos, understandable directions. Overall, thanks for sharing this 'ible!
When I need to bend (or cut) cardboard that is flat, not some tricky stuff on the inside of a box or something, I get out our handy flex-steel meter stick, mark the bend line with a pencil (or Sharpie, depending on the need for discreet neatness), and firmly hold down the meter stick and gently fold the cardboard in the direction I want it to bend. EZPZ.
4 years ago on Step 21
Very useful, thanks...
4 years ago
Brilliant. I wonder (and probably will try) if the wooden wheel can't reimplaced by another wheel shape (a bead for example).
Thank you or sharing.
Reply 4 years ago
I would think that how well a bead would work would depend greatly upon the diameter of the bead. It needs to be large enough to leave a wide enough "trough" for the fold but not too wide.
Sounds doable though.
4 years ago
Nice work! I really impressed by your graphics. What software do you use to create such detailed and nice looking drawings?
Reply 4 years ago
Thank you for your words! My favorite program is Autodesk Inventor (and of course Fusion 360). I used general solid and sheet modeling modes in this software. I think that drawing environment of Autodesk Inventor is most convinient tool to transform 3d models into the technical drawings. You can find some lessons about Inventor (and Fusion 360) on my youtube channel (https://www.youtube.com/channel/UCTJ7cITyWpfBBwuAEBv5skw)
4 years ago
Nice idea, and very useful, thank you.
I wonder how long it took you to make the tool, and how long it took you to write the Instructable! My best guess : 15 minutes and 6.5 hours each. But I am glad you documented it. Without it, I could never have worked it out. :-)
4 years ago
To those who have worked with cardboard, you know that a spline wheel ( which has a narrow groove in the wheel edge ) or a pizza cutter will work BUT the circular blades are too narrow and can cut and break through the cardboard which will weaken it. This wheel is wider which will compress the fold line and not break it. That is the difference in the design. Thank you nml2351 for your extremely detailed instructions and for sharing your idea. :)
4 years ago
I agree that it is a very detailed instructable and superbly illustrated, but surely a dough/pastry/pizza cutting wheel would work just as well?
Reply 4 years ago
Thanks for your feedback! As a truth I have never seen before dough cutting wheel. To work with dough In our family we use simple wooden cylinder - rolling pin ('skalka' in russian language) and knife. Today i searched for "dough cutting wheel" in Internet and see that it definitly similar to my device. But a shape of working surface on such tools is not convinient for a cardboard. This material will be burst by typical "dough cutting wheel". So the shape of wheel (roller) needs to have fillets and appropriate width. In any cases this weekend i plan to use my variant of wheel bender in to a project with 4 mm cardboard. And I will try to make report about it here.
4 years ago
Very comprehensive, many thanks.
4 years ago
This is a really good instructible, and your illustrations are outstanding. I do have to point out that what you've made is basically a screen spline tool:
https://www.lowes.com/pd/Saint-Gobain-ADFORS-8-in-Plastic-Screen-Rolling-Tool/3094501
4 years ago
A very concise instructable and I am sure it took quite a while to put together and you are to be congratulated for taking the time to do this.
Please be assured that I am not denigrating your efforts in any way.
However, it does seem like a little bit of an overkill to simply bend cardboard.
Question 4 years ago
i work with a LOT of cardboard for my projects. i was wondering, how well does it work when you use the tool "against the grain"?