I love working with metal, but I've always struggled to get perfect 90° bends. Generally, I'll stick the piece to be bent in the vise and smack it around until it's bent. Since it almost always bends crooked, I end up rebending - and generally just making a mess of it.
For my next project I was going to need to bend some cardboard, which inspired me to first tackle a bending brake. Since I knew I would end up bending things much harder than cardboard in the future, I designed the brake to handle thin aluminum and steel.
Inspiration for the design came from several other DIY brakes, such as this one by Improbable Construct and one by the Youtuber JDCD Design. Since I don't have easy access to a welder (and also try to avoid welding as I'm not terribly great at it), I modified the design to make it weld-free.
Step 1: What I Used
I used the following items for this build:
(1) 1/8" x 1.5" x 1.5" x 4' Steel Angle
(1) 1/8" x 2" x 3' Steel Plate
(1) 1/2" x 3' Steel Box
(1) 3/4" x 2.5" x 6' Dimensioned Board
(6) 1" x 5/16" Cap Screws
(6) 5/16" Lock Nuts
(10) 1" Drywall Screws
(2) 5/16" Wing Nuts
(2) 5/16" Washers
(2) 5/16" x 2.5" Carriage Bolts
(4) #10 x 1" Flat Head Machine Screws
(4) #10 Nuts
Spray Paint Primer
Blue Spray Paint
I used the following tools for this build:
(Note that these links were made using my Amazon Affiliates account. I get a small commission if you buy anything on Amazon using my links. You pay the same price and are helping support me in sharing projects like these. Thanks!)
Hacksaw (not mine but similar): http://amzn.to/2cKr0Ei
Circular Saw: http://amzn.to/2cp0gHU
Miter Saw: http://amzn.to/2cKrZnO
Dremel (a newer version of mine): http://amzn.to/2cu8Qn7
Drill Bits (not mine, but I like these): http://amzn.to/2coPscS
Forstner Bits (a larger set like mine): http://amzn.to/2dh66Zi
Metal File (similar to mine): http://amzn.to/2db0ALr
Box Wrenches: http://amzn.to/2db0BPR
Allen Keys (not mine, but the same thing): http://amzn.to/2ctX2RM
Step 2: Cut Stuff to Length
All of the metal and wood bits were first cut to length.
The 1.5" angle was cut in half to make two 2' pieces. This will be used to make the bending plate as well as the hold down clamp.
The 2" plate was cut to 2' in length. This will be used to form the smooth surface beneath the hold down clamp.
The 3/4" x 2.5" x 6' board was cut in half to make two 3' long boards. These boards will be glued together to form the base for the brake. The reason I used two thinner, dimensioned boards was that they were the thickest dimensioned boards I could find at Lowe's. 2x4's were not straight enough for this project and since I don't have a planer I typically buy my boards already planed.
Finally, the 1/2" x 3' box tube was cut in half to create two 1.5" pieces that will be used for the brake's handles.
Step 3: Cut Slots for Hinges in Angle
I wanted to use off-the-shelf hinges for my brake, but I didn't want to compromise on the location of the pivot point like many designs do. Ideally, the pivot point of the hinge should be directly inline with the bending line of the metal being bent.
In order to accomplish this, the hinges need to be located outside of the work area. In addition, the angle used for bending the metal needs to be slotted along it's bent edge to accommodate the barrel (the hingy part of the hinge) of the hinge. To maintain the strength of the angle, I chose to not run the slots the whole way to the end of the angle. By starting the slots at around 3/8" from the end of the angle, I was able to keep the two legs of the angle connected, which should help with the structural integrity of the angle. The hinge was laid on the angle to determine the length of these slots, which were made slightly longer than the hinge.
Cutting the slots proved to be a bit difficult since I did not run them to the end of the angle. I used my Dremel to help cut the flat spot to start the hacksaw in. After this it was simply a matter of cutting away the rest of the slot using the hacksaw. Since the hacksaw doesn't leave a particularly smooth (or straight) cut, I smoothed the slots out using a metal file.
Step 4: Cut Slots in Plate for Hinges
This step ended up being completely unnecessary as shall be shown, but I thought I would include it for completeness.
Next I cut slots in the steel plate to accommodate the barrels of the hinges.
Step 5: Drill Holes in Hold Down Angle
The second 2' piece of angle needs to be prepared for use as a hold-down clamp. Two points were marked 2.5" from each end of the angle. Since these points mark the location where holes need to be drilled, and since they lie on the bend in the angle, I created small flat spots at these points using a file.
I initially used a small (~1/8") drill bit to drill these holes since it fit nicely onto the flat spots. These holes were then enlarge to 5/16".
Step 6: Prepare Wood
This step also ended up being completely unnecessary, but here it is for completeness.
Since my initial design was to have the hinges lie beneath the flat plate, I cut recessed slots in the one 3' board to accommodate the hinges. I simply lowered the blade on my circular saw so that it protruded by 1/8" and made many cuts to create the groves.
I also needed to make angled cuts on the edge of the board to accommodate the barrels of the hinges. To do this, I locked the slides on my miter saw so that when the blade was fully brought down it would cut a 45° bevel on the edge of the board. Then I simply brought the blade down over and over again as I slid the board along the fence of the saw. I wasn't sure how this would work, but it ended up working out pretty well. Too bad I didn't need to do this.
Step 7: Attach Hinges to Board
The hinges were carefully aligned into the recesses on the board and clamped to hold their position. The centerline (pivot) of the hinges were aligned along the edge of the board. Once positioned, the hinges were carefully mounted to the board using drywall screws.
Step 8: Glue Boards Together
After the hinges were secured, their screws were partly removed as they protruded through the bottom of the board and would prevent the board from being glued to the second board. After coating the bottom of the first board with glue, I positioned it over the second board and re-tightened the hinge mounting screws. These screws held the boards together as the glue set up and no additional clamps were needed.
Step 9: Attach Plate
Recessed holes were drilled in the steel plate, which was then mounted above the hinges using four drywall screws. The edge of this plate was mounted flush with the edge of the board on the hinge side.
Step 10: Attach Bending Angle
Once the hinges and plate were attached to the board, the bending angle was temporarily clamped to the hinges to work out it's correct position. The edge of this bending angle needs to be perfectly inline with the pivot point of the hinges. The angle's edge will also be perfectly parallel to the edge of the steel plate and edge of the board. Once the position of the angle is correct, the holes in the hinges were used as guides for drilling 5/16" holes through the angle. The 1" cap screws were fitted through these holes, with the lock nuts being tightened onto them to secure the angle to the hinges.
Step 11: Design Correction
At this point, it became apparent that I had made a mistake in the original design of the brake. Ideally, the pivot point of the brake will lie perfectly inline with the bend line of the metal being bent. However, as I had designed the brake, the bending point was 1/8" above the pivot point of the hinge (see left side of drawing). The reason for this was that I had placed the steel plate over the hinges. If I were to place the steel plate at the same height as the hinges (inline with the surface of the hinges), the bend point and pivot point would be perfectly aligned (see right side of drawing). Since this was a relatively simple change to make, I decided to modify the brake.
Step 12: Trim Steel Plate
The main thing that needed to be changed for the new design was that the flat plate needed to be trimmed so that I would lie between the hinges. I simply cut the ends off the plate at the point where the slots for the hinges had ended. This plate ended up being around 17" long.
Step 13: Cut Slot for Cap Screw Heads
During the re-design I realized that I also needed to cut a slot in the side of the board to accommodate the heads of the cap screws used to mount the bending angle to the hinges. Without this slot, the cap head screws contact the board and keep the angle from fully opening. This is important because the bending angle needs to fully open to allow its face to be flush with the flat plate at the beginning of the bend. I cut a 3/8" deep slot in the side of the boards using the circular saw.
Step 14: Re-Attach Hinges and Plate
Since the hinges are now inline with the plate, I needed to flip the board so that the hinges were no longer recessed into the previously cut groves. I carefully positioned the flat plate and hinges and screwed the plate and hinges to the board. As seen in the last picture, the new groves for the cap screw heads allow the bending angle to fully open so that its face is flush with the plate. Also, since the pivot point is now inline with the bend point, the bending angle can be fully rotated to where it is flat against the plate.
Step 15: Notch the Hold Down
The ends of the hold down angle need to be notched to accommodate the hinges. I cut these notches using the hacksaw and cleaned them up with the metal file.
Step 16: Install Carriage Bolts
The carriage bolts are used to attach the hold down angle above the flat plate. I positioned the angle above the plate and used clamps to hold it in position. The front edge of the angle lies parallel to the edge of the plate, and is slightly inboard from the bend point. Using a 5/16" bit, I was angle to mark the position of the holes in the angle onto the hinges below. After the removing the angle, these marks were used to drill a small pilot hole through the hinge and board.
Flipping the board over, a 7/8" forstner bit was used to create a recess for the head of the carriage bolt. Next, the pilot hole was enlarged to 5/16", before the carriage bolt was fitted into it. I used a standard nut to tighten the carriage bolt into the wood as I was able to get it much tighter than I could with the wing nuts.
Step 17: Attach Handles
Two small holes were drilled in one end of both 1/2" box tubes to accommodate the 1" #10 screws. The box tubes were positioned on the bending angle just inboard of the hinges, and the holes in the tubes were continued through the angle. On the backside of the angle, the holes were countersunk to accommodate the heads of the screws (I used flat head screws). Once all the holes were drilled, the handles were bolted onto the bending angle.
Step 18: Bend Away
I primed and painted the brake to give in a nice finished look and was very happy with how it came out. Currently I don't have a permanent home for the brake, so I simply clamp the wood board to our kitchen table. This was the reason why I made the wood longer than the brake as I knew it would have to be used in this configuration for the time being.
I've only used it to bend a small piece of 1/16" aluminum (most likely similar to what I'll typically use it for), but it bent it like it was cheese. I'm confident it can handle a much wider piece of aluminum and even thin steel. The working area is around 17" wide, which should be more than wide enough for my current needs. I'm excited to finally be able to bend stuff correctly and know that this brake will get plenty of use in the future.