Introduction: DIY Bent Plywood Long Reach C-Clamps Without Bending Plywood! (Broken Sofa to Clamp!)

About: I've been making Instructables since I was 13. Now, I mostly make videos of my projects, however I'm still active here, so don't hesitate to reach out! Sick with a deadly disease called DIY-itis!

I love suddenly coming across an interesting object and thinking to myself: "THAT! Is a project!"
I was recently riding my scooter when I came across a broken sofa chair. I came closer to it, being reminded of the fact that I had been needing some leather for a project (since as you might know, the back of a sofa is full of leather that looks just like new), and then I saw the arm rest...

Maple plywood. Crazy thick! Bent in a c-shape.

"THAT! Is a homemade wooden c-clamp!"

...And also a great excuse for experimenting with cutting threads into wood for the threaded rod, making a clamp without a hex nut! No more wasting hours chiseling a perfectly straight hexagonal hole for the hex nut to fit, epoxying it in and waiting, like I've done several-too-many times in the past!

In this Instructable, I will show you how to make a long reach c-clamp, from bent plywood - without bending plywood, and by cutting threads in wood for the threaded rod which end up being WAY stronger than you'd think!

Let's get started!


(Watch the quick Youtube build video and see it in action!)

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Step 1: ​What You'll Need:

Want to make this project? Here's what you'll need, or at least what I used!

For those who aren't able to salvage parts for free, I've added some links to eBay below. Keep in mind that these parts can be acquired at a hardware store, or anywhere else online. If you don't see something that you think should be here, or would like to know more about a specific tool/part that I used, feel free to ask in the comments. *The eBay links below are affiliate links, meaning that I receive a small percentage of what you paid when buying through the link, at no extra cost to you.

I made it for FREE since I already had everything that was needed on hand.


Hardware, Materials & Consumables:



Subjects: Woodworking, Metalworking, Making Your Own Tools

Approximate Time: <2 hours

Difficulty: Medium


Step 2: Un-huge-ify the Bent Wood!

When I first unbolted the arm rest from the sofa chair, the shape the plywood was bent in didn't bother me, however it was too long, and needed to be cut down.

I clamped it in my vise and cut it with a jigsaw. I used a jigsaw blade that produces almost no tearout, the teeth are not only very fine, but they actually feel pretty smooth. Even though this is thick, hard plywood, I was surprised to see that it took me less than 2 minutes to cut both the top and the bottom with this type of blade. I can't find these blades anywhere online, though. Kinda unfortunate because they are really good, and I have no idea how long they will last since they don't feel sharp...

Don't ask me why an arm rest needs to be this strong. I think several people could sit on it without it even cracking!

Step 3: Drill a Hole for the Threaded Rod

After experimenting on a few test pieces I found out that tapping a hole for a 1/2" threaded rod works best in a 10mm hole, not any bit ⁽ᶰᵒ ᵖᵘᶰ ᶦᶰᵗᵉᶰᵈᵉᵈ⁾ larger or smaller.

I drilled very slowly through the top piece of the bent plywood, stopping every couple seconds and adjusting my grip on the drill to make sure I was drilling as straight as I could. This is really important as if the threaded rod doesn't go straight down, it can bend or ruin the threads of the clamp.

I kept having to imagine that the drill bit was longer and would hit the bottom part of the clamp at 90 degrees since I was drilling into the part of the plywood which was bent. I think brad point drills work better than regular twist drills.

Step 4: Make a Thread Tap to Tap Threads in Wood (turn Any Bolt Into a Thread Tap!)

You won't believe how easy it is to tap threads into large holes in wood!

I also made a quick video on how to make one a few weeks ago: How to Make a Wood Thread Tap WITHOUT an Angle Grinder! (Drill Powered)

...But here are written instructions:

I first rounded off the tip of the threaded rod with my bench grinder. This is done so to make it easier to insert it into the piece of wood, especially hardwood that's hard to compress.

Next, I clamped it in my vise, and with 2 cutting discs in the mandrel of my rotary tool, I started cutting grooves in the side on the bolt. This can take quite a while depending on your rotary tool, and also creates a lot of dust and heat - make sure to keep the bolt cool so it doesn't lose its hardness in case it has been hardened. I cut three wide grooves into both of the taps that I have made so far, and it seems to work really well. I think the more grooves you make, the more cutting edges there will be and the easier it will be to cut, but the bigger each groove is, the easier it will be for the sawdust to fall - which I don't think matters since wood crumbles and falls anyway, unlike metal of plastic.

I then twisted two hex nuts onto the threaded rod, locking them together, making it easy to grip onto them to twist the rod accurately in wood.

If you don't own a rotary tool, I think you should be able to to make it using only a hacksaw.

Step 5: Tap Threads in the Clamp!

Time to tap the threads!

If this is your first time tapping holes, I recommend practicing a few times on some scrap wood.

After twisting and locking two hex nuts onto the tap, which I explained in the previous step, I made sure my small locking pliers were locked tightly, I started twisting the tap, applying some downward pressure, but not too much. It's more important to make sure the tap is entering the hole as straight as possible.

It took me a few minutes to tap the hole, mainly because I kept backing out to make sure the threads were being made properly.

I think the result is really good - I'm not sure even a storebought tap would produce a better result!

Step 6: Hand Carving a Handle for the Threaded Rod, Sooooo Relaxing!

I decided to try hand carving a wooden handle for the clamp, little did I know how much time it would take, however it was worth every second, carving into wood is so relaxing and fun, also a great excuse to test out my new homemade carving knife that I made from an old spade drill bit!

I first rummaged around in my collection of wood, looking for a piece of wood that wasn't too small or too big for the handle. Once I found the one I had in mind, I clamped it in my vise, and drilled a 12mm hole into the endgrain using a spade bit, which was surprisingly easy, unlike drilling into Beech! I think this is some type of cheap maple that I scavenged from a broken Ikea chair.

I used my homemade carving knife to carve the piece of wood, stopping every couple of minutes to sharpen the knife, unhypnotizing myself, I guess :)

Almost 2 hours later, I decided that enough was enough and that I have more things to do other than wood carving!

Step 7: Attach the Handle to the Threaded Rod

To glue the threaded rod in the handle, I first thought of epoxying it in, but then changed my mind since I spent so much time making the handle, and if I ever wanted to remove it and use it for a different project, it would be pretty much impossible.

First, I inserted the threaded rod (rusted side) into the hole that was previously drilled in the handle, and then I clamped it in my vise, and drilled a hole through the handle and into the threaded rod. Only one broken drill bit later, I was able to hammer in a small metal rod, and when I reached the point where I was unable to hammer it in more with a hammer, I used a punch to push it in more. You might also want to epoxy only the rod inside, so it doesn't move.

I then screwed it into the clamp, being careful to not accidentally ruin the wooden threads on the first few turns.

Step 8: Make the Clamp Pad

I wanted to make a simple clamp pad to stop the tip of the screw from damaging the wood I would be clamping with the clamp.

I drilled a 10mm hole in a small block of wood, and screwed in the threaded rod. A 10mm hole is exactly the point where the threads of the threaded rod dig slightly into wood, but don't produce too much friction, allowing me to still screw it in by hand. Since my carving knife was on the workbench, I also gave the edges a slight chamfer.

I unfortunately, didn't drill the hole straight enough, so when clamping it causes some issues. I think I will have to improve on this simple idea.


Step 9: Use!

Woah. This is huge. It has almost twice as much the reach of my biggest bar clamp! And can clamp 8" pieces of wood if I remove the clamp pad! Where do I store it?!

If you think this is a weird clamp, prepare for an even weirder homemade c-clamp - coming soon!

See it in action, on Youtube!

Some more thoughts:

  • I actually scavenged two of these c-shaped bent plywood pieces, so if you have any others ideas for projects I should make with the other one, leave them in the comments below!
  • How strong do you think it is? I want to measure it but don't want to break it!
  • If you're like me and love building your own tools, don't forget to check out The Ultimate Collection of DIY Workshop Tools, which contains dozens of Instructables on all sorts of homemade tools, perfect for your budget!

I also will be giving away free Instructables premium memberships (please read before commenting) to members that make their own bent plywood clamps based on this Instructable. Will you be the first one?


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Epilog Challenge 9

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Epilog Challenge 9