How to Make an Auto-Reversing Electric Roller Bender From Spare Parts

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In a previous guide, we showed you how to make a vintage hand-cranked drill. As awesome as that machine is, it is only as good as you are physically strong. 

Wouldn't it be great to have a machine with a bit more power, and perhaps, make it semi-automatic? As it turns out you can. 

Follow this simple guide, and video, to find out how. 

As you can imagine, you'll need some things to get you started.

Materials and gear needed

• Scrap metal tubular lengths
• Scrap metal rods and shafts
• Scrap ball bearings
• Scrap or reclaimed  reversible electric motor
• Scrap or reclaimed gears and chains
• Acetone
• Masking tape
• Metallic spray paints
• Angle grinder
• Mini lathe
• Belt sander
• Welding gear and safety equipment
• Screwdriver set
• Basic tools (wrench, screwdrivers, etc)

Step 1: Find or source the parts you need

Since this project is primarily made from reclaimed scrap metal bits, you'll need to either do the same, or source new alternative pieces. You'll need a variety of tubular metal, metal rods, chains, gears, and an old motor, to name but a few pieces. 

Depending on the condition of the parts you've managed to source, you may need to tidy up or trim down some parts to your needs. If, for example, some lengths of tubular steel have cut edges, use your angle grinder to clean them up. 

Ensure you take all the necessary safety precautions when doing this. So be sure to wear gloves, etc. 

With that complete, cut off the top of one side of the tubular steel beam to leave a u-shaped profile length of steel. 

With that done, use your angle grinder to clean off any rust, and weld lines, etc. Next, mark two angled lines at either end of the length of tubular steel, and cut the beam using your angle grinder. 

This will be used as the main body of the pipe bending machine.

With that done, smooth down and polish any cut edges of the beam as needed. If required, continue to clean off the rust, etc, using a rotary steel brush sander. 

With that complete, either cut a length of smaller bore tubular steel, or take two equal small lengths, place them underneath the u-shaped piece, and weld them into place. 

Step 2: Make the rollers for the machine

Next, take three equal small lengths of steel rod, or cut down a longer one. These will be repurposed as the main rollers for the pipe bender. 

Next, take the lengths of the rod and secure them in your lathe. Bore a small hole through the center of each end of each rod. This will act as a mounting point for the tailstock and lock the tailstock into place. 

With that done, machine each rod into the final rod shapes required for the pipe bender. No dimensions are provided, but yours will depend entirely on the pieces of scrap metal you've managed to get your hands on. 

The narrowest part of each rod will need to be slightly smaller than the inner bore of the ball bearings you managed to salvage. 

Rinse and repeat for the other two rods. Note that the two endmost rollers will have longer end shafts than the central-most roller rod. 

Next, route the top and bottom of each end of the roller shafts. 

With that done, take the chain gears you've managed to source, and modify their axial bores to match the shape of the ends of the rods. The routed shapes we created earlier are to provide a basic locking mechanism to hold the rod and gears firmly together. 

With some of the other gears, machine-off the teeth, and modify the axial bores so they can fit snugly on the main body of each roller. 

These will be used as the main "grips" for the lengths of metal to be bent in the machine. 

With that done, use old steel pipes and bolts to create mounting brackets for the roller's ball bearings. In this case, small rings of metal pipe were cut.

These rings were then cut in half, and bolts were welded are strategic points around the outside. Once completed, the pieces were polished up as needed. 

With that complete, sink some holes through each central ring from the rollers. Thread the holes, and then secure the rings into place to the rollers as needed. 

Polish and trim down the pieces as needed. 

Step 3: Mount the drive chain 

Using the ball bearing mounts you created earlier, mount the two end rollers into place at either end of the main assembly base. Add two toothed gears, and the chain, around one side of the rollers, pull taught and weld the pieces into place.

With the middle (shortest) roller, use a series of steel beams to create a mounting frame for the roller. Next, use more pieces of the steel lengths to make a hinge point for the roller to position, and remove, the roller in the very center of the pipe bending machine rig. 

This will be used to define the angle of bend of the pipe when the machine is in operation.

With that done, weld a square metal plate to the top of the adjustable roller frame. Next, create a threaded rod arm assembly to connect, and adjust, the hinged roller with the base of the assembly. 

This assembly will be used to "squeeze" the pipe/length of metal into a curved shape. 

This will require you to bore holes through lengths of steel rod and modify barrel nuts etc. As with the rest of the machine, the dimensions will vary depending on the parts you have to hand. 

Step 4: Mount and connect the motor to the drive chain

Next, take your electrical motor and decide where you want it mounted on the machine. Either use existing parts or machine replacement ones, to connect the motor to your designated drive gear of the chain. 

With that done, machine some brackets to mount the motor directly to the frame of the main machine. 

With that done, take a small length of metal, a spring, and some nuts and bolts. Using these pieces, rig up two sprung lever mechanisms for either end of the machine. 

This will be used to reverse the direction of the motor when the switch(s) are flicked on and off. 

With that done, take your metal switches, and rig up mounting posts for them to the main assembly within the swept areas of the levers. When the lever is triggered, it should be able to clip and flick the switch into its position. 

Step 5: Wire up the motor and switch

The next step is to wire up the motor and the switches. Open up the main wiring housing of the motor, clean up the wiring if needed, and connect the main control wires for the motor with the terminals of the switch(s).

You will likely need to use some spare or scrap lengths of insulated wire to do this. How you connect the switch to the motor will depend entirely on the make and model of the motor you've managed to salvage. 

With that done, connect a power supply to the motor and test the action of the machine. In this case, the rollers dragged the test pipe too fast, so you may need to add an electrical or mechanical addition to slow down the rotation of the motor axle. 

Next, whittle a short length of wood to form handles for a manual detachable crank for the machine. Fashion and weld into place a mounting pin for each wooden handle, and secure the wooden handles into place on the crank. 

Step 6: Paint the main components of the machine

With the main elements of the pipe bending machine now complete, disassemble the machine and paint the parts as desired. 

In his case, the main bolts, gears, etc., will be painted black. 

Parts of the motor were also powder-coated in light gray. 

The old motor, and welded parts of the machine, were then cleaned up using a solvent, and bent or buckled parts of the motor were also beaten back into shape. 

With the parts, all now cleaned and prepared, the frame positions of the machine should also be painted. In this case, these parts have been spray-painted in a similar tone to the motor. 

Other parts, like the ball bearing flanges, and lever arms, were also painted red. Some of the main parts of the machine frame were also given a coat of chrome-colored paint too. 

If desired, varnish or lacquer any wooden parts too. Once complete, leave all parts to fully dry. 

Step 7: Complete the final assembly and test the machine

For any and all moving parts of the machine, add a small amount of lubricant. Examples include the handles, chain, gears, rollers, etc. 

With that done, begin to reassemble the machine as needed. 

If needed, reassemble the motor, and connect it to the main assembly as needed. Wire up the motor with the end switches, as before, and complete the assembly as needed.

With that done, your electrical-powered pipe bender is now ready to be used in anger. 

Take some lengths of pipe, and other lengths of metal, and place them into the machine as needed. Grip the lengths of metal inside the adjustable flanges on the center of the roller, and tighten the securing bolts as needed. 

With that done, add some clamps with a long handle, or clamp scrap pieces of metal at 90-degrees to the main pipe in such as way that they can push the levers. 

If everything has gone to plan, your pipe bending machine should work perfectly! Congratulations.

If you enjoyed this project, you might enjoy making some other awesome pieces of kit for your workshop? How about, for example, restoring an old floor tire pressure gauge?