Well I am on the home stretch with the bending brake which is a good thing since it seems that I have too many other projects competing for my attention. Both the gazebo table and the lathe stand need to see completion first then I’ll be onto something new.
Where did I finish off last time? Ah yes…I needed to fabricate the clamping system, then some way of taking the flex out of the clamping fingers, and finally some sort of a leverage system.
I continue to build with no firm plan and so I start hunting around the shop for stuff I can make use of. Some 1” threaded rod, a couple of 1” coupler nuts, and some left over 2” pipe from the metal bender should work just fine. I need a way to clamp the 3” channel to the 6” channel so that the 10 gauge steel will stay put when it gets cut and then bent. I trimmed the coupler nuts down short enough so that they would fit inside the 6” channel. I clamped the 3” and 6” channel together and drilled a 1” hole through the ends. The 1” coupler nut then got welded to the underside of the 6” channel. I admit reading all this is kinda boring, just look at the picture ok? Instead of purchasing 1” bolts and washers I cut some threaded rod to the required length and welded on the left over chunks I cut from the coupler nut. Tossed them into the lathe chuck and faced the end to clean them up. I then shaved .500” off the 2” pipe to create a couple of heavy duty washers. There you have it, a completed clamping system. It’s not elaborate but it is highly effective.
Don’t stop now, I’m almost there. Next is a solution required for taking the flex out of the clamping fingers of the brake when the bend is being made. The problem is that since only the ends of the 3” channel are clamped, and since the clamping fingers are bolted to the 3” channel, and since I carved out a .250” slot down the center of the 3” channel, the whole length of channel wants to twist during the bend. I decided I needed something to clamp the clamp. It’s like airplane building; I need to implement redundant systems. So a hunting we will go for more scrap to build with. After inspecting 4 metal piles I came up with a section of 4” x 3/8” flat bar and a length of ½” cold rolled round bar. It’s time for more bridge building and therefore a second truss system will be added to the build. The plan is this. Make a couple more clamping bolts a bit longer then the first, drill a couple of 1” holes in the ends of the 4” flat bar, then fabricate a truss to give the set up some rigidity. Again…just look at the pictures, I’m doing my best to try and make all this sound interesting. When it came time to weld the ½” cold rolled round bar onto the 4” flat bar in order to marry the 2 of them into a truss I decided to build a warp into the assembly. If I could concave the flat bar then it would give me even more clamping force once it is bolted down solid onto the 3” channel. Before welding the truss I propped the ends of the flat bar up with some 1/8” filler rod and clamped the center. It then all got pretensioned and welded which resulted in a very rigid, concave truss. Great! 2 down 1 to go.
Leverage system, what to do. As much as I wanted to make things look pretty I opted to weld on a couple of handle receivers which have some locking set screws. The pipe was leftover from the BBQ project and would allow me to use a couple of ¾” round bars as handles. The build process was no more then cutting a couple lengths of pipe to proper size, then drilling and tapping them so they each would accept an 8 mm socket head screw. Unfortunately I have no chunks of 3/4” rod lying around. I’ll have to keep my eyes open for some freebies; I plan on coming under $100 on the complete build.
Well here it is…official test time. It has taken a few weeks, and some “fly by the seat of my pants” engineering but I have something that resembles a bending brake. Who am I kidding; I’m not sure this contraption looks much like any brake I’ve ever seen. Oh well, if it functions and actually bends something then I guess it will have earned its title.
First up, a scrap piece of 10 gauge sheet metal. I marked a bend line and clamped it into position under the 3” channel. I took some time to set the circular saws shoe plate into proper position on the guide plate. I am shooting for a 90 degree bend therefore I need more then 1 width of a saw kerf. If I set the saw blade slightly off center I will be able to make a cutting pass in 1 direction and then head back in the other direction essentially making 2 cuts side by side. This should hopefully give me a wide enough cut to allow for the 90 degree bent.
Ok, enough talk…here is the video. I did my best to make it quick however it still took a hair over 5 minutes to shoot. I think the video does a good job of explaining what I have been writing about over the past few weeks. If you have been following the build and feel lost then this is your reward for hanging in there. If you haven’t been following the build and have just stumbled your way directly to the video then good on you, you just saved yourself 3 blog posts of confusing descriptions.
The bend came out as good as I hoped for from the start. It’s a tight, clean, straight bend. The cut line does not impact the strength of the bend for my purposes, it feels rock solid. The bend actually took a bit more force then I had anticipated. I am unsure how much force will be required for a longer length however I suspect getting some proper handles on the machine, and then being able to bend from both ends, will help. The saw cut worked out get. The line was straight, the depth was fairly consistent, and the cutting width of 2 kerfs was perfect. I would have to call the project a success. I have a few little touch ups to do yet. I am contemplating throwing a coat of paint on it yet, maybe I’ll paint the metal bender at the same time. Time to get back onto the other projects.