Intro: Super Strong Bar Clamp
So in this instructable, I am going to show you how I made these super strong bar clamp. I think for everyone who does woodworking and metalworking uses clamps a lot but they are quite costly to purchase. Same thing happened to me as well that's why instead of buying some clamp I decided to build my own. These are completely made out of scratch material and if you are new to welding then I think this might be a good project for you because the material thickness is more enough which can bear rough welding work as well and you have no need to worry about that because you can grind it to make it looked clean. Although I highly recommend to go with cold rolled Steel bars because they are dead straight and you have no need to worry about any wiggling in your material. Unfortunately, I didn't get that material that's why I go with the hot rolled steel flat bars.
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Step 1: Material and Tools Used
So for this build, you don't need to have a bunch of tools in your shop, the whole build is possible to make with just an angle grinder and Welding set. For this project, I use the chop saw as well. Since I have that so I think its good to get an advantage. Although an angle grinder have the capability to do this job entirely. But make sure to follow the safety rules before doing these work. Following are the list of tools and their attachments I used for this build.
- Welding Set
- Welding Electrode
- Chop saw
- Angle Grinder
- Cut-off wheel
- Flap disk
- Paint Brush
- C Clamp
As the law of choice also applies to material as well. For this build, I go with Mild steel flat bar. Although I wanted to go with cold rolled steel but I didn't get that at my local metal supply dealer, so that's why I go with hot-rolled steel and you can see in my builds too. The material has a slight deformation in it. Since I have enough material I can avoid that. Following is the list of material I used for this build.
- 6 X 30 mm Mild steel Bars
- M12 Thread road
- 25mm round pipe
- M12 Coupling Nut
- 4 mm thick round coin
- File handles
- Two part Epoxy
Step 2: Material Cutting
So starting of this build by cutting down this long bars into more manageable size. Since I have an advantage of the chop saw that's why I go with it but you can do it entirely with the angle grinder as well. For my own use, I decided to make 18 bar clamps and each of them has a different length. For the length, I choose 3 dimensions 14 inches 26 inches and 38 inches. Once the main bar has been cut down I cut down the top portion off the jaws. Here one thing is to be no down that you don't have to cut both the top and bottom jaws of the same length because in the bottom jaw, you have to weld the coupling nut and you need to calculate this length. In my build, I made this mistake. Once the bigger pieces of top and bottom jaw has been cut down I cut some small pieces from the same material which are going to be welded in those jaws. Although it is not necessary to cut it down in smaller size but if you want to decrease the weight of your clamps then I think going for smaller pieces is a smart move. You can cut down both the smaller section of same dimensions as well it is not necessary to make one slightly bigger than the other.
Cutting of clamping Pieces
For the clamping action, I used the piece of thread rod. The part which is acting pressure on to the job is made out of one-inch diameter pipe having round coin welded at its one end and onto the another and a washer is being welded. The pipe has been cut down to the length of 3⁄4”. The inside diameter of the pipe is around 7⁄8” of an inch. The length of the threaded rod is around 7 inches which I also cut on to the chop saw.
Step 3: Deburring
Since I am using the chop saw that's why during the cutting there are burrs created at the end of each piece that's why I have to deburr everything. For that, I used my angle grinder and a grinding disc. The grinding disc is quite aggressive so it will remove the burrs quite faster rate and some time a lot more than required. I think 60 grit flap disk works well in this step. For the grinding disc I am using this special soft grinding disc and I found that this is very effective onto the mild steel. I also deburr the edge of thread rod as well.
Step 4: Chamfering and Tapering
To get the better welding joints I decided to chamfer the edges before welding so that it creates a good joint because, in the end, it has to bear all the clamping force when the clamp is in action. I also chamfer the main bar at its one end as well so that the smaller pieces make a better joint with the main bar.
To make the lower jaw movable and lockable I grind one side of both the pieces which are going to face the main bar at the slight taper, I think angle around 4 to 5 degree is sufficient for the clamping action. The main thing to note down is that do not taper the species to a too much angle as it makes your Jaw more wobbly. Although that works as well but didn't look that well.
Step 5: Welding of All Components
So after cutting all the parts we actually create some components which are ready to group up into one body. For that, I first welded the small pieces which are not tapered one welded to the main bar where I made the chamfer. I place it on a flat metal plate so that during the welding it will not warp. One thing has to be noticed that do not make a continuous weld in the first step. I first tack weld from the ends and then flip the piece and start the welding onto the back side. So those tack welds prevent the movement of Pieces during the continuous weld. I do this to create the fix Jaw of my clamp. Then I welded the longer pieces for the fixed jaw. So after doing that we completed 40% of our work. Movable jaw. Welding the movable jaw is quite tricky and you have to make sure that the position of the tapered pieces align to the correct direction so that the job will freely move to one side but locked in another side. I place a Scrap piece of the bar whose dimensions are exactly same as the main bar I am using for my clamps placed in between those tapered species and then tack weld onto the bigger piece of bottom jaw. Then I test the movement and it worked quite well. Before welding the second bigger plate of the movable jaw I place. 8 mm thick piece of metal shim on to those tapered pieces and then welded permanently. If you don't place those shim the jaw will move quite tightly onto that bar and creates trouble. After that, I insert the movable jaw into that bar and tested which is working very well but there I noticed one major flaw of my design and that is I made both top and bottom jaw of the same length. Since I am going to weld coupling nut to the bottom movable jaw and if I weld that the clamping action slightly shifts away from its centre line. But then I cut that access portion by calculating the exact length of my bottom jaw so that they lie in the same line during the clamping action. Once I get the required length of the bottom jaw welded the coupling nut and complete the bottom jaw assembly. To provide a bearing surface to the fixed jaw I welded 4mm thick 40 mm diameter coin so that it provides a good holding pressure onto the job.
Step 6: Pressure Assembly
To exert pressure on to the workpiece I need something which can hold the workpiece between those jaws. For that first of all, I welded M12 not onto the threaded rod and weld it. Then I hold the rod into the drill machine and hold the grinder facing upward into the vice. Then I start grinding the nut into slightly spherical shape so that it will swivel inside that cylindrical pieces. For the cylindrical piece, I welded the same coin at the cylinder edge. Then I inserted that rod into that cylinder with some grease and cover it up with the help of washer and just tack weld at some places. Now the pressure assembly is completed.
Step 7: Slight Improvement in Look and Feel
For the aesthetic purpose, I cut down top jaw slightly tapered angle so that it would look like a factory product. I think it definitely increases the beauty of the clamp and also reduces the weight to some extent without harming the strength of the jaw too much.
Step 8: Painting
Now, most of the work has been finished for the clamps and they are ready for the paint job. I choose orange and black theme for the clamps. To paint the fixed jaw I decided to dip the whole portion into the paint can so that it will be painted as fast as possible. By doing this paint layer has been everywhere onto the job and this layer is quite thick as well than the normal way when we apply with the paint brush. Onto the bar, only one coat of paint is done because jaw has to move back a forth so eventually after some usage it's going to be scraped off. But I think in one coat the paint covers the bars completely and there is no room left for the rust to enter into the metal bar. I think those shim also helps here to prevent the paint surface from scraping off.
Step 9: Final Assembly
For final assembly, I entered the lower jaw into the bar but here one thing has to be noticed that the lower jaw move up and down by tilting it slightly upward direction so that whenever clamps are in action the downward pressure force locked it into place because of that tapered sections in the lower jaw. Once I get the right orientation I screwed that pressure assembly to it because if you do it wrong its very time consuming to correct this. For the handle of the clamps to bring them into action I used files to handle. These are quite cheap around 15₹ and made out of polyethene. They have a slight disadvantage and that is the slippery surface but it didn't bother anymore unless you have oily hands. I drilled 12 mm holes for the thread road into those handles and then fix it to its place with the help of two-part epoxy. It stands to its position very nicely but I think if it slips I am definitely going to insert pin so that the handle will not slip during tightening.
Step 10: Finally
Now the clamps are ready to use. Currently, I don't have anything to show how much force they generate because I don't have that thing. Even a place where I can clamp it and then hang onto it. But as the quality, they have they are working very well. I used them in my workshop cabinet build video you can check them on my youtube channel. So if you like this make sure to subscribe like and comment down below. I am extremely happy to read your comments.
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