Introduction: Metal Bender

No matter what your hobby, sometimes you need to bend some light weight metal into nice, circular shapes.  This instructable will show you how to make a metal roller out of old printer rollers and some angle iron. 

So far, I have used this bender to make circles out of 1x1/16 aluminum for some of my hobby robots, to bend some 1x1/8 inch aluminum into a perfect circle for a US First Robotics high school team I mentor (Go Team 1631), and to bend two 5 inch wide 1/8 inch steel sheets 9 feet long for a fire pit I am making (but that’s another instructable).

This instructable will have you cutting metal and braising.  Don’t forget all the safety rules involved with each of these activities.  If you are new to any of the tasks below, I recommend looking up safety tips on the internet before trying something new.  As you will see in step 10 “Next Time” I made a few errors on this one, but I finished with all my fingers and toes intact.  That’s a good thing.

This is my first of hopefully many instructables, so if something doesn’t make sense, just ask, and I’ll try to explain it better.

Step 1: Parts and Tools

Parts list
Qty     Item
 3       Printer rollers removed from old printers
 2       4 ft pieces of 1x1 Angle Iron
 1       3 ft piece of ¼ in C-Channel
 1       3 ft piece of 2 x ¼ inch flat metal
 1       Conduit pipe holder
 1       ¾ x 9 inch bolt and nut
          Scrap rebar or other metal
          Finishing nails
Tape Measure
Metal saw
Magnetic 90 deg holder
3lb Sledge Hammer

Step 2: Rollers

Start with the printer rollers.  Take apart the old printers until you are left with just the printer roller.  Use a screwdriver to make sure all extra pieces are removed.  You only want the roller with its metal bar core.  The rollers should be close in size, but do not have to be the exact same size.  One roller should have an extended metal core.  That one you will use for the top roller.  You will need the extended core to attach a handle. 

You can cut the remaining two rollers so the overall length is the same using your metal saw.  Make sure you leave at least ½ inch or more metal core exposed beyond the rubber on each side so you can attach them to the bottom rail.

Step 3: Bottom Rails

Cut 2 pieces of angle iron 18 inches in length.  These will be used for the bottom rails of the bender, and will hold the bottom 2 rollers.  Lay out where you want the bottom rollers.  Center them on the angle iron, and space them the width of the 3rd roller plus ¼ inch apart.  This will allow the top roller to pass between the two bottom rollers and still leave room for a piece of 1/8 inch metal. 

If the rollers or their metal core are not the same size, the holes will not be lined up even on the bottom rail.  That is okay, it is more important to make sure the rollers are level, and drill the holes where they need to be.

Step 4: Top Roller Holder

To make the holder for the top roller, cut a piece of C-Channel based on the following calculation.  Take the length of the longest rubber part on your bottom two rollers then add 5 and ½ inches.  The longer rubber part of my two bottom rollers was 9 and ½ inches long, so I cut my C-Channel 15 inches long.

Make a mark 2 and ½ inches in from both sides of the C-Channel.  Carefully notch out a ½ in channel on the outside of the mark on both sides.  The notch should go from 2 to 2 and ½ inches from the ends. This is needed so the metal will not bunch up when you bend the sides down. 

Mark the bend point at 2 and ½ inches with a chisel, and bend both sides of the holder down using a piece of 2x4 to help keep the bend even.  After you bend both sides, the length of the roller holder will be ½ inch longer than the longer rubber part of the two bottom rollers.  Mine was 10 inches in length (9 and ½ inch rubber piece plus ½ inch). 

Mark the center of each side for a hole, and drill a hole large enough to fit the metal core of the 3rd rubber roller.

Step 5: Risers

Cut 4 pieces of angle iron 9 inches long to act as risers that will make a slot for the top roller holder to slide in.  For each riser, you need to cut one side of the 1x1 angle iron to ½ inch wide.  This is needed to make a slot for the 3rd roller’s metal core.  It’s okay if the edges are not very straight (mine weren’t), you just need the room. 

Now is also a good time to drill a hole in each of the roller’s metal core for a cotter pin (finishing nail) to keep them in place.

Step 6: Braising

It’s time to start braising.  First, braise each corner of the 3rd roller holder. 

Next, take the first bottom rail and place it on your work area.  Take the first riser and braise it 8 inches in from the end of the rail.  This should place it just inside one of the bottom roller holes.  Position the riser so the cut side of the angle iron will make a slot for the 3rd roller holder (cut side towards the middle of the rail).  Make sure the riser is a true 90 degrees from the bottom rail. 

Braise the remaining 3 risers making sure they are aligned between the two rails, and the 3rd roller holder slides easily between them.

Step 7: Finish Top Roller Holder

Finish the 3rd roller holder by adding a cup to hold the push bolt and some metal for strength.  Start by rolling a conduit holder to a circle that the end of the bolt will fit in. 

Cut a 9 and ½ inch and 4 inch piece of flat metal (your long piece may differ in size depending on the size of your bottom roller).  Braise the 9 and ½ in piece on the inside of the 3rd roller holder channel.  Center and braise the 4 inch piece of flat metal to the top.  Finally, braise the cup to the center of the top.

Step 8: Top Bolt Holder

To attach the top bolt holder you first cut a piece of C-Channel and a piece of flat metal the length of your 3rd roller holder.  I cut my top bolt holder pieces 10 inches in length.  Braise the flat metal in the C-Channel, and drill or melt a hold in the center big enough for the ¾ in bolt to easily slide through (I melted the hole in mine with a torch). 

Slide the bolt through the top, and tighten the nut on the bottom, so you can braise the nut to the bottom of the flat metal.  The bolt should easily screw up and down after you are done. 

To complete this step, weld the top bolt holder in place at the top edge of the risers, and twist the bolt until it fits into the cup on the top of the 3rd roller holder.

When you screw the bolt up, the 3rd roller holder will not move up, you need to move it up with your hand, but as you are rolling a piece of metal, it will squeeze down on the metal and give you a tighter curve with a twist of the bolt.

Step 9: Finish Project

To finish the project, measure and cut two pieces of angle iron to fit the front and back of the bender.  Don’t make it too tight so the rollers can easily move, or too loose that they fall out. 

For the turning handle, cut a 6 inch piece of C-Channel, and drill a hole in the center that fits over the 3rd roller metal core.  Braise some rebar or other scrap metal to give you some leverage, and attach the handle with some finishing nails to fill the hole and get a tight fit.

Step 10: Next Time

If I did this again, I would have made a few changes. 

First, I would have used bushings in each of the holes for the roller cores.  They will help keep the rollers from slipping or sticking when you use the bender.  Without the bushings you can back off the pressure and stop the slipping and sticking. 

Second, I would make the sides of the 3rd roller holder longer than 2 inches.  I’d make them at least 3 inches long to make sure the roller does not rub on the holder.  Since I already had the piece together, I shaved down the size of my 3rd roller by putting it in a drill press, and sanding it down as it spun.  It worked, but I would highly NOT recommend that process for anyone. 

Third, braising is just a form of welding.  I originally thought I was welding everything together, but I was using braising rod instead of welding rod.  It works for this type of project, but it’s not as strong. 

Finally, I would have made a better attachment for the handle.  The nails move around and slip hold of the roller core.  So, I first used a vice grip as a handle, but that started to strip the metal core, especially when I was trying to bend some metal that was too big for the bender.  I ended up using the handle from a tap and die set.  The handle squeezed on the roller core very nice and it’s now a permanent fixture on the bender.

There you go…  Hope this was helpful, and will get you started on your own metal bender or other fun project.
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