Introduction: DIY Metal Bending Tool

DIY Metal Bending tool for bending of reinforcing steel, rod, round, flat, square bars.

It is very suitable for the making of concrete reinforcement cages.

The bender can do bents using the guides of main unit
at 7-12-17-22-27-32-37-42-47 cm

and with the use of the addition

at 5-10-15-20-25-30-35-40-45 cm

Also it is easy and simple to modified, according to your needs.

The plans are avaliable at (.skp) format at "Plan Files Step"

you will need Google SketchUp8 or any newer to open it.

It is a quick and simple build, made from leftover materials, and most of the needed tools exists at any toolbox.

Here is a video of this build, and the tests of the bends with reinforcement bars and flat bars

I have use a disk saw machine to cutting the piece for the bushing, but if you haven't such tool, isn't critical or prohibitive.

Using your angle grinder, a very simple jig and your bench vise, you can do the cut easily and pretty good. (See Step "Preparation of Bushing / Pivot Set").

Also if you haven't the needed taps for tapping, then you can weld nuts. (You can see the sketch at Step "Plan files")

Step 1: Tools and Materials


  1. Angle grinder 115 or 125mm
  2. Cutting disk ø115 x 1mm – (ø4 ½” x 0.04”) or ø125 x 1mm – (ø 5” x 0.04”)
  3. Grinding disk
  4. Saw machine (optional but helpful if any)
  5. Hacksaw
  6. Drill or Drill Press
  7. Welding machine
  8. Magnetic welding square
  9. Tape measure & Vernier
  10. Center punch & Pen Scriber
  11. Flat File
  12. Clamps or Vice grips
  13. Drill bits: ø4mm, ø5mm, ø10mm, ø10.2mm, ø10.5mm, ø12mm, ø16mm,
  14. Taps set: M6x1 & M12x1.75
  15. Tap handle
  16. Countersink
  17. Wrench 19mm
  18. Allen Wrench 5mm & 10mm
  19. Bench vise


  1. 1pcs Tube 38x38x3mm x500mm (main unit)
  2. 1pcs Round stock steel ø25/14x32mm (bushing)
  3. 1pcs Round stock steel ø34/12x20mm (roller die) if it is from hardened steel will be much better (Do Not use a ball bearing as roller die, it is dangerous)
  4. 1pcs Rod ø16x70mm 1pcs (rotating pivot)
  5. 1pcs Rod ø10x600mm or 9pcs x57mm & 1pcs x22mm
  6. 1pcs Flat bar 30x10~15x100mm (bending unit)
  7. 1pcs Flat bar 30x3x100mm (addition)
  8. 1pcs square tube 20x20x1.5mm or heavier (handle)
  9. Hex Socket Bolts: 1pcs M12x60mm, 1pcs M10x30mm
  10. Hex Bolts: 1pcs M12x40mm
  11. Hex Socket Bolts headless 1pcs M6x10mm
  12. Nuts: 4pcs M12, 1pcs M10, 1pcs M16
  13. Washers: 2pcs M12
  14. A piece Scotch Brite, for finishing/polishing of the rotating pivot

Step 2: Plan Files

You can open the files using the free version of google SketchUp8 or any newer.

Step 3: Preparation of Bushing / Pivot Set

Remember Safety First.

Welding Cutting and Grinding Tools are Dangerous!

Do it at your own Risk!

Use Always the Suitable Protective Equipment.

Cut a piece of 32mm length from the ø25/14mm round stock steel, using a saw machine, if any.
Or make a jig at your bench vise (see the sketch or file)

Mount a piece of angle-iron, in the vise,

Mark the point of cut at the stock steel

Place the steel into the angle-iron, so as the cutting point to be just next to end of the angle-iron

Use a clamp and a piece of steel and create a stop at left side of angle-iron, so as, your stock steel to can't move to the left.

Using the end of the angle-iron as guide, slide the cutting disk over it, and rotating the stock steel by hand, do the cut, (the cutting disk is not needing to pass across).

Use a file, to smoothen the profiles.

Do a centers punch at the point that will become the hole onto the tube (38x38x3x500mm (main unit)).

Do the hole at the tube, starting with ø4mm drill bit and completing with ø16mm drill bit.

Resize the hole of bushing from ø14mm to ø16mm and clean up the edges using a countersink.

Polish the ø16mm rod/axle using the drill press and a piece Scotch Brite.

Then cut a piece 70mm length of this rod for bushing's pivot.

Step 4: Bending Unit

For the bending unit I decided to use something from the leftover stuff that was good enough and needed to do only one hole and a M12 thread.

Don't worry, isn't needed to make a construction like this that is little complicated,

you can use a flat bar 30x10~15x100mm (You can find the plan at "Plans Step").

Weld the bushing,

drill a ø10.2 hole (bushing center > hole center at base = 38mm)

use a M12 set taps to cut the threads.

Mount the roller die (ø34/12x20mm) into the hole at the base of bending unit.
Socket Bolt \ washer \ roller-die \ washer \ up-side nut \ base \ down-side nut.

The distance between the bolt's head and nut must be the sum of [roller+2 washers+(1~1,5mm)]

so the roller to can be rotate freely.

I have used the extra (down-side) nut because my base isn't solid and each side of 4mm thickness, can has only 2 complete threads (the pitch of M12 coarse thread is 1.75mm).

A solid base of 10mm thickness, can be has almost 6 complete threads, that is good enough.

Make a handle of square tube 20x20x1.5mm and mount onto the base at a 140°~150° angle.

Heat up a piece of plastic tube and pass it onto the tube.

Step 5: Main Unit / Cuts & Guides

The main unit is a simple tube (38x38x3x500mm).
I have made the pivot holes at an earlier step (Preparation of Bushing / Pivot Set) but before the installation of guides need to do some cuts at the edge of tube.

Needed 30mm space at the edge of the vertical sides, so the bending unit to can rotate and rounding the corners at the horizontal sides.

Mark a center line for the guides.

This line must be at the whole length of tube at 16mm from back side to front.

The center of first guide must be at a distance 42mm from the center of the pivot hole.

All guides must have the same distance (50mm) between them.

Mark and then Center punches all points.

Start drilling the holes with ø4mm drill bit.

Complete the holes with ø10mm drill bit.

Cut from ø10mm rod 9 pieces 57mm length.

Place the pieces/guides into the holes.

Weld all pieces/guides at the down side of tube.

The Main unit is almost ready.

Step 6: Main Unit / Adding a Pivot Base

To attaching the bending unit to main unit needs to make a small base for the pivot.

Will need a M16 nut abroach with a ø16mm drill bit and a M6 headless socket bolt.

Do a ø5mm hole in the middle of the nut side, and then use a M6 set taps to cut the threads.

Insert the pivot into the nut, adjust, and then fasten the screw.

Pass the pivot into the holes at the main unit from down side.

Weld the nut to the main unit.

Step 7: Main Unit / Thickness Adjuster

For the making of Thickness Adjuster needed one M12x40mm bolt, two M12 nuts and two small pieces of steel scrap.

Weld a nut on a piece of steel, then with the help of a magnetic square adjust and weld at the back side of tube, at the point behind of the first guide.

Please follow the process on photos, I think that is easier than the text.

Step 8: Main Unit / Addition Guide

The tool as is can do bends as follows:
at the first guide 70mm

at the second 70+50=120mm

at the third 120+50=170mm and so on.

Making a small and simple addition we can double the range of bends as follows:

at the first guide 50mm

at the second 50+50=100mm

at the third 100+50=150mm and so on.

For this addition will need a flat bar 30x3x100mm ant a piece of rod bar ø10x22mm.

Mark a line at 8mm from the front side, at flat bar.

Do a center punch mark over the line at 10mm from the left edge

do a second at 32mm and a third at 82mm.

At the first one, do a ø10mm hole.

At the second and third, do ø10.5~11mm holes.

Turn the flat bar upside down,

using a countersink or a bigger drill bit, do the first hole conical.

Grind the edge of (ø10x22mm) rod to be conical.

Weld and grind the weld so to be smooth.

Step 9: Bending Tests

The tool is ready.

Tested and the results are prety good.

You can see the whole video here

You can see the tool in action here

Thanks for your reading.
Good Luck if you try it.

Never say I can't do it.

Necessity is the mother of invention.


Build a Tool Contest 2017

Participated in the
Build a Tool Contest 2017