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Picture of 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 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

Picture of Gather Materials / Tools Needed and Used

Material List

  • (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
  • (4) 3/8" x 16" Knobs (5 Pack) or make your own!

Tools Needed and Used

* This contains Amazon affiliate links. But let me be honest here: it's far easier for me to post a link to the product as a visual then to just list a description. This should make getting the items you need to finish this build far easier and more fun in the long run. If you do choose to buy something through the links, thank you. If you appreciate this instructable I'd be happy to get a like and subscribe on my youtube channel as well as a follow here, as well as a comment.

To be honest I'm sceptical. One of the most important aspects of cauls (that's the thing the pipes are replacing in this design) is that they are made (usually by the woodworker himself) to have SPRING in them - to mean that they are fractionally thicker in the middle than the ends.

This is so that when pressure is applied at the ends (only place it can be applied) EQUAL PRESSURE is also exerted IN THE MIDDLE.

This design with a straight metal bar, whether round or square CANNOT PROVIDE PRESSURE IN THE MIDDLE. This means that uneven tightening of one end or the other will affect the flatness of the boards being clamped because the middle boards can slip up or down a fraction.

If you tried to add a central block or something to add central pressure all you will do end up bending the bar. Now you're going to say you can bend the bar to do the same thing - look around and tell me how you're going to achieve two bent bars that are IDENTICAL and with the correct amount of bend - literally 2mm over 1000mm span.

Doing it in wood however is simple for any semi proficient woodworker.

Cauls having a "bulge" or spring as it's properly known in the centre is a design that's been used for CENTURIES, for good reason.

Why you decided to make cauls out of expensive metal compared to free scrap hardwood, I don't know, but it's your money I guess.

Except now you're advocating people spend money to do something they can do for free following age old proven methods.

My cauls cost me nothing - use a very similar method, WILL keep the middle boards where they should be, and mine are infinitely adjustable, which yours are not.

Sorry but not a fan of "reinventing the wheel, that costs more money"
Hi Rafe, your argument doesn't hold up here I'm afraid - and that is because you are applying the same thinking about the properties of wood; i.e. that it bends; to round metal bars - which don't. When you state very emphatically that "round bar CANNOT PROVIDE PRESSURE IN THE MIDDLE". This is incorrect - round bar when used in the application described here and in the way instructed *will not bend*. And therefore it provides pressure as evenly as the screws at either end are tightened down. Physics 101.

Also - you (and others to be fair) keep banging on about the cost of this pipe - HE gets it cheap - and I'm guessing that since he's American - there are about 300 million people or more that can also get it cheap. Just because you cannot is not a legitimate reason for criticism of any kind. And besides - where'd you get that "scrap" wood that you used? Did it just appear magically in your hands or did you pay for it at some point. Doesn't matter if it's left over from some other project .. did you pay for it? I bet you did.
Moot point anyway because people like yourself are hell bent on bashing down ideas - ANY ideas that are not the same as yours or are not centuries old. Your favourite words are can't don't didn't won't wasn't isn't and never.

I'm making myself a set of these panel clamps for sure - fantastic solution to a problem, easy to produce and for not much money - even here in my country which is expensive.

Have a great day in the shop.
Well, first you are correct in that the electrical conduit won't work. It will certainly bend easily. And will be compressed out of round by the knobs. But you are wrong about the square tubing. It is quite easy to put a slight bend in it, just by elevating the ends a small amount and using a board hit the middle. This is just as easy as putting a slight bend in a piece of wood. Your method will certainly work, but so will the methods of others. You shouldn't dismiss them so quickly just because it's not the way you would do it.
It is also not necessary to use cauls with a bend in them. Just tighten the clamps loosely and made from about anything and drive wedges under them. In fact, it is very easy to get even pressure that way.
Not many people have hardwood scrapes with good grain to make clamps with. If you were to buy punched metal square tubing the holes are already there. At HomeDepot about $3 per foot. At a metal supply house, about $1.
Make_Things (author)  Rafe Zetter4 days ago
Lot of hostility here. That’s okay. I’ve made a number of things that people automatically shoot down, using their own logic to dictate why something won’t work. That’s okay. I assume that you don't know there are metal tubing panel clamps sold right now for hundreds of dollars. You can paint targets on those scammers, I'm not trying to make money on these plans.

Rockler sells panel clamps for $64.99..."on sale" for $47.99. That's for ONE. One panel clamp won't get you anything more than a ton of anger.

The reviews for these are quite bad. They're thin metal and flimsy.

Then I found some called "Panel Max Glue Press" for $249 for 3 of them. That's $83 a piece.

Mine cost about $20, which will get you 2 panel clamp sets. I'm not making any money here, I thought it would be a good project that someone would enjoy making. If anything, I wasted about $100 of my own money buying a heap of tubing trying to find the best way to make this project work.

I really don't appreciate you storming in here and accusing me of making someone use their hard earned money instead of using garbage throw away scrap wood to make something that you have no idea works or not. I would never, ever, try to scam any other user into spending money on something that I knew didn't work, which is why I spent a considerable amount of my time and resources making sure people have an easy method of making these so that it works for them.

I guess this all looks easy. Maybe a couple hours filming, 30 minutes of editing, a half hour to write an instructable, right? Wrong. This project took me 3 weeks to complete. 60-70 hours to gather materials, waste materials to completion. I spent a few of those nights and days starring at the ceiling trying to figure out the best method to make something work.

I spent 6 hours in editing of the video alone, including voiceover work which came to 3 pages of dialoguel (which I wrote out before recording). Another two hours of recording the audio. The instructable took me off and on about a week to write up, after I had submitted the video to youtube. That's a week of writing and cutting the project up where I didn't do anything else in my workshop. One day alone was the equivalent of a full work day, 8 hours.

Am I asking that you love this? No. I'm not asking for anything from you or anyone else. This is a labor of love only. I enjoy helping others make things. So why would I spend so much time trying to make this work if I knew that my own results were phony and that somebody else wouldn't be able to do what I did?

Thank you!

Very good idea on clamp making. Well presented and great organization. I do recommend anyone wishing to make some clamps use square tubing. The holes will be much easier to drill accurately and it will be much stronger. Round tubing will tend to flatten and bend, especially conduit. You can get square tubing in home improvement stores. Lowes or Home Depot in my area. Also Tractor Supply. If you use aluminum square tubing it can easily be cut on the table saw using a wood cutting blade. At those home improvement stores, you can also get circular saw blades that are made to cut steel. If you were to make several of these clamps you might want to make a story board.
Make_Things (author)  yrralguthrie4 days ago
Thank you, those are much appreciated words!

As far as square tubing goes, it is a lot more expensive (nearly 50% more). If money is less of an issue, skip round and square and go with unistrut. It’s far more rigid and the holes are drilled out already.

Of course, I wouldn’t use this instructable at that point as this instructable was a means of making an expensive tools for far less expense. For what it does at 26”, I’m proud to say that it performs very well and I’ve used this on a few projects to say that I’ve never had any problems with it.

Besides that, using the technique I stumbled upon uses the round tubing to a greater advantage, allowing you to spring the rod into your project. I’m not entirely sure how well that would work with square tubing.

I personally wouldn’t recommend using aluminum as that will be an even more expensive method and I would expect aluminum to be far weaker.

I am totally appreciative to all those that find ways to make this an even better instructable, but since I’ve never used the methods that you have recommended, I can’t recommend them myself. If you or someone else has used those other materials...please!, don’t hesitate to give me a heads up!

Thank you yrralguthrie!
Nice project well done . I am sure this tool works well.
Did to know you can purchase panel clamping system from Amazon for C$ 50 ?
You supply the wood cauls. I have one set and other than fiddling with the set up they work well.
DCT 4-Way Pressure Release Clamp –
Make_Things (author)  leslielimpid4 days ago
Thank you!

Yeah, I’ve seen them. These cost $20-30 to make, at least for these 26” sections.

I don’t know, I have more fun making the tools I use. Thanks for the heads up!
Mad44007 days ago
This is a really well presented instructable.
Make_Things (author)  Mad44006 days ago
Thank you!

Sometimes I feel like I’m treating the reader like they’re incompetent...but I really want to make sure I word it just right and make sure they’re able to make it work.

At the end of this instructable I was sweating bullets as I knew there were so many things that could go wrong.

I appreciate your kind words, it helps ease my anxiety!
The worst thing a guide writer can do is assume the reader has a certain level of skill and skim over steps in the process. (Of course it's fair to expect the reader has at least the basic ability to use the tools and equipment required for the job).

A good "how to" is clear and concise, but a great guide also includes the "why to".
Why certain materials were selected, why steps were done in a defined ordered and the possible pitfalls involved.
This allows the reader the opportunity to substitute materials on the list for what they might already have lying around or is readily available to them. It also offers the flexibility to adapt the guide to suit their needs and be successful in the attempt. Which is what the true spirit of DIY is all about.
Once again, well done and keep the instructables coming!
RobT957 days ago
One of the required items is a black marker - is a Sharpie acceptable or should I invest in a Skerple?
Make_Things (author)  RobT956 days ago
Unfortunately, Ch nese markers are the only accepted form of marking device, all others are count rfeit.

Love you buddy!