Introduction: Conduit Panel Clamps (cheap!)
For years now I've been using buckets of water, string, hoards of bar clamps, pipe clamps and even logs (no really) to hold down projects that needed to be glued and clamped edge to edge. I've used router bits, dowel jigs and biscuits jointers to cut grooves, holes and slots to join my wood. But one common problem plagued me like the...well, aphorisms aside, keeping my wood panels straight, free from bows and cracks in the joints.
I figured this was just the way it was supposed to be. Want a straight bunch of boards? Buy manufactured panels at the big box stores. Want a cutting board that's free of cracks? Use wood putty. It 'twas a bleak life that lay before me. Sad, twisted and full of cracks. About a month ago I caught a conversation online about a particular clamping system. I had neverheard of it before...panel clamps? Is that a clamp that glues big box store panels together? I shook the magic google 8-ball and found that glorious product...in all it's glory! Only $199 for a set of 2 clamps! Wait, what?! $199 for 4 square tubes and bolts?! This was absurd! And then, like a quick flicker of light in a bleak, costly world, my hardware store education kicked in. This is what I came up with.
(This project is for a 26" set ((4) 30" tubes) of panel clamps. Of course, you can extend the project to longer lengths, but all dimensions and materials will be used to make (2) sets of clamps.)
Step 1: Gather Materials / Tools Needed and Used
- (1) 1"x10' Length of EMT Conduit
- (4) 3/8" x 6" Carriage bolts
- (3) 3/8" x 4" Sacrificial carriage bolts (these aren't absolutely necessary, but you'll be doing work with them, and might damage the threads)
- (4) 3/8" Nuts
- (4) 3/8" Washers
- (4) #8 x 1" Wood screws
- 1 1/8" x 4" x 3/4" Hardwood
- (2) 4" x 4 1/2" Pieces of plywood
- 3 1/2" x 8 1/2" x 5/8" Hardwood
- A piece of scrap wood the size of your conduit, length is a few inches (for centering)
- 3" Aluminum Tubing, cut in 5/8" sections
Tools Needed and Used
- 4" Drill Press Clamp (for steel): https://amzn.to/2N38PZY This is an absolute must! If you don't have one, follow my link or hit the hardware store.
- Drill Press
- Table saw
- Bandsaw (semi optional)
- Ange Grinder with a cut off disk (or a hacksaw)
- File or flap disk (for a grinder)
- Step drill bit (VERY HIGHLY recommended): https://amzn.to/2NN0zhi
- 3/8" Titanium drill bit: https://amzn.to/2MSuIMj
- Sand paper (I used a strip sander)
- Black marker
- 30" Straight edge (I used a yardstick)
- Drill press punch
- 3/8" Brad point bit
- Carpenter's square (6" works great)
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Step 2: Cutting Pipes to Size
We'll start this off by cutting our 1" x 10' pipe into 4 equal segments. Because the pipes are 120 inches long, we'll need to cut them at 30" intervals. I used a grinder with a cut off disk but you could very easily use a hacksaw. It's important that you measure each length before cutting instead of using a tape measure and marking all 4 lengths at once.
Be sure each end is smooth as sharp edges...well they're just no fun at all. I used a belt sander but you can get away with some sandpaper or some sort of disc sander, grinder, grandpa Buck's false teeth...you get the picture.
Step 3: Sizing Up Your Tubes and Adding Faces
I can't begin to tell you how absolutely important this next step is. It's important for many reasons, and all reasons point to accuracy. You need this buggar to be as accurate as it can be when you drill downward into the bottom end. Don't worry...don't worry...we've got this. I'll admit, it took me a lot of trial and error to get the right way...or heck, just the best right way I could come up with, but I've made 5 sets of clamps now and the way I'm going to share should work for you.
The developers of this super tubing did something magical for us all. When they welded the tubing together they left behind a seem in the inside of the tube. We'll transfer the seem from the inside to the edge of the hole and to the outside. After we've marked the outside, we'll need a straight edge that's as long as our tubing. We'll simply connect the outside dots with the straight edge and draw a line that's about 3" in on both sides of each tube.
So far, not too hard, right? Don't get proud of yourself yet. Double check all your marks, inside and out. Make absolutely sure your outside reflects the identical side of the seem. Double check that you made straight lines on both sides of each tube...this is so absolutely critical.
Now we'll take a scrap piece of wood and line up all of our tubes against it. Because we have two tubes for each clamp, we'll want to take away any chance of error by pairing each up. We'll label each set with a number and an "F" for front and "B" for back. Be absolutely sure you don't do what I did and get them mixed up in the middle. You are the preacher and each tube couple will be married proper
Step 4: Marking Our Crosshairs
Okay, I'll admit this next step was a dumb move on my part...or the lack of part of this step. Whatever...you live you learn, right? The first time I did this I figured I'd just measure over 2 inches from both sides, since I wanted to leave a hole at 2 inches and 28 inches respectively. I mean, that makes sense, right? Wrong (I'm sorry if that was an ego burn). IF all 4 pieces of the pipe had been cut to precise measurement (30 inches) from a factory, that idea would have been bulletproof. But instead, we cut those pipes to length, which means all the pipes will be at different lengths. Since we are looking for exact measurements between each set of tubing, we'll need to be more precise than that. Silly me.
To combat that problem we'll measure from the beginning of all the tubes on towards the end of the tubing. We'll use a block of wood to line up our sets of tubes, making sure that the labels are together from the previous step, and we'll draw a crossline on both tubes at the 2" mark and on the 28" mark. Be absolutely sure the tubes are together, square up against the block of wood...this is serious business. After the first set of tubing is finished, move on to the second set.
Step 5: Setting Up Our Vice
I know I've made a lot of drill press clamps and jigs in the past, but there's one thing I won't make, and that's a drill press vice for drilling steel. Instead, I highly recommend buying one (which is a rare thing for me to say). I do have a link to one in my materials list if you'd like to give it a look. But for anything involving the drilling of metal, I shy far away from using my wooden vices. Most big box stores will sell that style to you very inexpensively.
Now then, we'll need to set up our drill so that we drill precise holes in our tubing. We'll first measure our tubing to get the perfect distance it'll take up in our vice. Set the pipe end in and squeeze down enough that that tube knows we mean business...but not enough that we'll dent it. Once it is secure, measure the inside jaw width. We'll use that measurement and cut a piece of wood to the same length on our table saw. My tubing was 1 and 5/32 inches, but who knows, maybe different manufactures use different thicknesses or have different specifications.
After that width has been cut and you've measured it twice to make absolutely sure it's the exact size, find the exact middle on the board and leave a pencil mark. Flip your ruler over and double check it. Check it till you are sick of doing it.
Place it in your vice, but check to make sure that where you set the marked wood will fall down in the insides of the vice. That means that when you go to drill the tubing you won't hit the inner workings of the vice. Once that's in place, use an awl and mark the center of that wood piece. Next, bring it to your drill press and either use a small drill bit or a brad point bit and set it in the indentation you put in with your awl. If you can lock your drill press quill in place, do it now. Then use whatever you need to use to lock that drill press vice down flat to the table. Lock your table. Everything needs to be locked and ready to go. Also be sure you have a place for your tubing to go as you drill so it doesn't hit the back of the drill press column (angling your vice at an angle will prevent that).
Step 6: Drill Our Starter, Guide Bolts
The reason I use the term "Guide Bolts" is due to the idea that each clamp needs a couple guides before we start getting serious with the heavy drilling. Because each hole needs to be parallel to its corresponding hole below, we needed to make sure that we drilled out each hole as perfectly as we could. Now we need to finish these important guide holes by, again, making sure we are absolutely perfect in our drilling.
Let's review (not for you, my loyal reader, but to help make sure I've gotten things as easy to understand as I can). We need 2 EMT tubes for each clamp. Each will be 30" in length. Each 30" clamp has 2 crosshairs that are directly on the center (welded line) of each tube. Each crosshair has been punched. We've got identical marks on the 2" mark and the 28" mark. Our vice is centered on the drill and at an angle to prevent our conduit from hitting the column.
Now we'll drill our first hole using a quarter inch titanium bit (or go with a smaller bit as the video explains), but watch how the tip behaves inside the punch we made. If it wanders left or right, front or back, we'll need to move the tube slightly. When everything seems to fit and flow just right, press down and let the drill press do its work. It will break through the top layer and work its way to the bottom. Don't force it. Let the bit do it's job.
After all holes have been drilled out we'll either switch to our final 3/8" size or (and this is the method I prefer) jump to a step bit. Step bits have come down a whole lot in recent years and are very handy, especially at keeping the center as you drill, so long as you are in a generally straight up and down motion. I actually drilled my holes without clamping it down in my vice (I still used the vice), and it centered itself as I went. The entire process was over much quicker than that 1/4" hole I started with.
Step 7: Installing Our Bolts and Checking for Accuracy
Now we'll run our 3/8" x 4" carriage bolts through each set of tubes, remembering to keep the labels from "Step 3" facing the way we marked them (Clamp number, F & B). We'll add a nut between each tube and use a wrench to tighten it down slightly before adding the tube through the top of the bolt. From this point we'll add a nut on the top of just one side, leaving the other side free.
If there's a problem and you have a bolt that won't slide through both pipes...don't panic! One of those sides should line up with the other side. Run a bolt through the first tube, put your nut on, add the second tube. Use a couple pieces of plywood that are about 4 inches long by four inches wide and a clamp and clamp it up. Use a 3/8" bit and run it through the side that doesn't match. Check the video if this doesn't make sense or send me a message here at the comments below.
Step 8: Making an Easy Repeatable Jig
I know, I know, I always manage to throw a jig in somewhere. But this is about the most helpful jig you could ever want. This jig will allow you to do 3 things:
- It will keep both pipes lined up on the vertical when you drill.
- It evenly spaces each hole.
- It makes finding center so much easier.
Of course, it won't look like much after you've completed the task due to the drill bit, so realize this is a disposable jig. Also, a big note: one of the holes will always be used for drilling while the other hole will always contain a bolt directed into the previously drilled hole.
To make the jig, we'll need the 3 pieces of wood specified in the materials list:
- 1 1/8" x 4" Hardwood
- (2) 4" x 4 1/2" Pieces of plywood
If you noticed that I'm not using a 1 5/32" wide piece of hardwood (as that is the width of my pipe), very astute observation! In this case I chose to round down as 37/64" (to find the center) was a number my eyes probably couldn't find on a ruler, which gave it a slightly snugger feel.
We'll drill two 3/8" holes on the block of hardwood at 3/4 inches in from both sides, directly in the center. Next we'll take the (2) pieces of plywood and attach them to either side of the block. We'll finish the jig by attaching those sides with (4) #8 x 1" wood screws (be sure to use pilot holes before screwing them in).
Step 9: Making Quick Work With the Jig
Now we'll take the bottom tube and run our sacrificial 3/8" x 4" carriage bolts through it. We'll do this on both sides of the tube, snugging a nut on top of the tube when we're done which will allow metal debris to exit. We'll add the second tube, making sure we keep our tags lined up (F & B). This time, though, we'll only put one nut on. We'll do this so that we can start our jig on the side without the nut.
As I said in the video, this is where the fun begins. Having a repeatable jig means:
- You don't need to do any measuring or any worrying about whether or not the holes will line up from one tube to the next.
- Things will go much quicker and accuracy isn't something you need to burden yourself with nearly as much.
- You don't need to start with a pilot hole and work your way up like previous steps.
Having said all that, we still want to make sure we're square to the drill press table. Being slightly askew means that we'll do damage to our jig, and we want it to hold up for as long as possible. To keep things square, we'll use a square...or a carpenter's square. We'll square things up before and while we press the drill bit through the jig and our tubing. It'll also be important to use a piece of scrap wood that's the same thickness of the nut between the tubes to keep them from flexing as you drill.
After we've made our first hole with the jig, be sure to go back to that carriage bolt and add a nut. We'll simply slide the jig over and use a 3/8" x 4" sacrificial bolt going top down through the jig and into the new hole drilled. We'll make sure it has penetrated the first tube and is through the second. At this point it is totally up to you as to how many holes you'd like to add.
With my set up it was necessary, after all holes had been drilled out, to remove the jig and finish drilling through the bottom of the tubing as my drill bit wasn't long enough. I kept the tubes together and used each of the holes I had previously drilled as a way to keep my last hole lined up.
Step 10: Cleaning Each Pipe and Setting the Carriage Neck
This is definitely an obvious part of this step, but be sure to clean each hole. Even a slightly raised hole from the cuttings can cause a major problem for you as it will leave marks on your project later on. You can do this by lightly running a grinder and a flap disk or just a file. Be thorough.
Once we've done that we'll line up our pipes again, still using our sacrificial bolts. Be sure that the bolts are strung through both tubes in the image I've included, with the head end of the carriage bolt against the "B" tube. You'll notice on the carriage bolt the square neck is much larger than the 3/8" hole you drilled. You could now try to push that neck through the 3/8 inch hole, but you'll do more damage that way. Instead, let's remove the bolt and use either a 7/16" inch drill bit (will work but be careful) or a step bit that drills 7/16" holes (best). Remember, we only need to drill that side of the pipe out.
Once we've drilled the 7/16" hole on the "back" pipe of each set of clamps, we'll reinsert the sacrificial 3/8" x 4" bolts through again as we did in the last paragraph. From this point you can either use a hammer to knock the carriage bolt in or just a nut on the opposite side, snugging in the bolt carefully.
VERY IMPORTANT: When you go to use your panel clamps, be sure the carriage bolt is set inside the tubing before clamping down with the knob. I know this is obvious, but one mistake could strip out your hole.
Step 11: Adding Knobs, Cutting Spacers
Of course, none of my projects would be complete without a knob of some sort attached to it (I think I direct more people to my knob instructable than any of the others). If you'd love to make your own knob with a few ideas I have, hit that instructable up. Otherwise, there are plenty of vendors on and offline eager to sell you your own knobs. I will remind you we're looking for a knob with a 3/8" nut.
You're going to need 4 of these for this project. If you decide to make more clamps, keep in mind you'll always want two knobs for each clamp.
Another important thing we'll want to do is create a spacer that'll work between the tubing. This will act as protection to keep your threads from getting damaged, and (probably more importantly) your project from getting a bunch of groove marks embedded in it. We'll use a 3/8" aluminum (or steel) tubing to do this. Alternatively, you can use longer carriage bolts as they'll sometimes not use threading near the head.
Since most of my projects are less than 3/4" of an inch in thickness, I made my spacers 5/8 by using a hacksaw to cut the aluminum to length. As was before, remember you'll need 2 spacers for each clamp you choose to build. Fortunately, aluminum 3/8" tubing can be fairly inexpensive (I paid about five dollars for 3' at my local hardware store). Check out your local hardware store, or, again, buy longer carriage bolts without the threading.
Step 12: The Final Stretch! Shims
We're almost there!
This step can be as optional as you want it to be. If you have pipe clamps, you don't need to go any further. If you want to keep this as simple as possible, using shims is the easy way to go, but don't go weak on this one...be sure you use some sort of hardwood. Admittedly, I had one shim crack on me when I was hitting it into place, so try changing grain direction if it's a problem (my grain direction ran towards the bolts).
We'll take the 3 1/2" x 8 1/2" x 5/8" piece of hardwood and draw a line at a diagonal. With a bandsaw we'll cut the piece in half making 2 triangles. We'll need to remember that the thickness of both pieces will need to be less than the thickness of the project. Because (again) I don't usually ever join things together that are less than 3/4", 5/8" is what I used.
Step 13: Tips, Problems and Troubleshooting...and Beyond!
Congratulations, you've made yourself an inexpensive set of panel clamps! I've designed this section as a place where I can throw information if you run into any problems, as there are some things I've found along the way to enhance the strength of these clamps. As I have had an enormous amount of views on the video, I will be directing a lot of people here to study issues that they may have or concerns.
First of all, the build that we performed here was for a 26" clamp. Can this design work for a 48" clamp? Definitely! I know this because I just recently clamped together a 48" x 96" wall, using 3 of these panel clamps. It worked extremely well, but there are definitely some things that you need to know before trying to accomplish this.
Long Panel Builds:
- You will most definitely want to use pipe clamps for something this large. You could get away with shims, but they'd need to be longer in width (same height). If I were going to attempt this with shims, I would probably make the shims 16" long and use hard maple. I was able to clamp the boards together with the shims, but cracked one due to the angle that was applied. With pipe clamps, I was able to get a better squeeze and ended up using only 2 of them altogether (that beats the 7 or 8 I had to use the last time I made a wall, as well as a dozen hand clamps).
- The best way to get the most clamping power into the middle (which is crucial) with these panel clamps is by using a trick I found. At first, when I put the clamps on and tightened down, I found that the center of my panel clamps were raising up. That is, the tube was lifting off the wood project. Oh no! I thought it was a failure until I started to (sheepishly) realize what was happening. The knobs I were turning were causing the tubes on the outside of the clamps to bend down while the center came up. This was an obvious mistake as the very edges of my wood project were stopping the energy I was placing on the clamps.
Instead, I had to find a way to counter this problem. By putting a part of the thickness of the wood I was clamping behind the knobs (on the outer edges of the bolts) and using a very slight wood shim on top of it, I could now direct that energy above the project edge and squeeze down the middle and sides without issue. This is sort of a spring effect that is quite effective and countering the issue and giving the clamp an enormous amount of power.
I can't tell you, dear reader, how many confrontations I've had with people over this one single issue. In this step I've included pictures and labeled them as Example A, B and C.
- Be sure you stagger the crowns of your boards. It is poor form to take a bunch of boards and find the best sides of each board to glue together for the best face. You have to sight the end of each board and look at the crown (the way in which the wood cups). The best practice is to alternately rotate those crowns. The first one will either cup up or cup down. The next will do the opposite. Doing this will help ensure that the boards stay flatter; and in time it will keep your panel from bowing.
- You may need to clamp your project to a flat table. This is true with all panel clamps but is less of a problem with the number of panel clamps you use. Due to the wood you are using, and sometimes whether or not you haven't alternated your crowns (back in the last tip), you may have a twisted result at the end (diagonals bend up or down). Using a clamp on the diagonals, attached to a flat table can help with this problem.
- A greater number of panel clamps used will give you a better outcome. With my wall that I made I used only 3 panel clamps. Two clamps would have been a bad idea. Five panel clamps would have been better. Ten, even better.
- Your clamps should sit on the outer edges, especially during large glue ups. If you want to move them in a little, that would be fine but you might need short bar clamps clamped where the boards line up with each other.
- Be sure to use the straightest wood that you can use! These clamps aren't miracle workers! Trying to glue up boards that are curled upward three inches would a disaster.
Short Panel Builds (Cutting Boards, etc etc):
- Depending on the properties of your boards, you may need to use step #2 from "Long Panel Builds". This means that if you have a problem with your boards being extremely twisted or warped in any way, you'll need to shim the outside edge.
- Be sure to put the clamps on the outside of the edge, especially if your boards have any twists in them.
- Use small knobs! I know the knobs I made are large, but they were mainly made that way for my much larger build. If you plan on just using the panel clamps used in this instructable, keep the knobs small, in the 2-3" size.
- Use butcher wax (suggested by ronin4711...a viewer!) to coat the tubing. This will keep glue from sticking to them and won't do any damage to your project.
- Using door shims (wooden or composite) can make it a lot easier to clamp something when you need to bend the bar inward.
- When you go to put away your panel clamps, be sure the knobs are tightened when you put the clamps away...not tight, but not loose either. This will prevent any damage to the bolt threads and then hole you created for the neck of the carriage bolt.
If you have any information you'd like to add here, leave a message so we can include it...I'll credit you for it!
Step 14: Thank You!
It has been such a pleasure to make plans here at Instructables, and I appreciate all the people that take a look at the ideas I've had (some good, some not so good) in the last year. Please throw out a comment or two, I love reading thoughts, compliments or concerns.
If this instructable didn't work for you, please let me know and I'll try to help you out the best way I can. I really want each and every attempt at all my instructables to be happy successes as I know how heartbreaking it can be to find an idea online and have it be a failure (It's happened to me on youtube a few times from other makers in the past).
Follow me here, I'd love to have you in for the ride!
Runner Up in the