DIY Sheet Metal Bender Brake




Introduction: DIY Sheet Metal Bender Brake

Sheet Metal Bender Brake 805mm

Mounted on a Hydraulic Portable Table

I love metalworking, is my favorite hobby.

So for my need to build a stainless steel barbecue I decided to make a sheet metal bender brake.

It isn't a so complicated construction and no needed expensive materials (total cost of materials less than 30€) neither special machine tools.

Also if you interested to see some modifications of this brake;
you can visit my instructable page "DIY Sheet Metal Brake Fully Modified"

What is a sheet metal brake

A brake is a metalworking machine that allows the bending of sheet metal.
A cornice brake only allows for simple bends and creases, while a box-and-pan brake also allows one to form box and pan shapes. It is also known as a bending machine or bending brake or as a sheet metal folder or just a folder.

Cornice brake

A cornice brake has a solid clamping bar, the full width of the machine; thus, it can only make straight bends, the entire width of the workpiece.

Box-and-pan brake

In a box-and-pan brake, the clamping bar includes several removable blocks, which may be removed and rearranged to permit bending of restricted areas of a piece of sheet metal or of already partially formed pieces. After bending, a box or pan form is then completed by screw, solder, weld, rivet, or other metal fixing process.

Press brake

This is a more complex tool that forms predetermined bends by clamping the workpiece between a matching punch and die.

wikipedia article:

Step 1: Tools and Materials


1. Angle grinder 115mm 4 ½” or 125mm 5” Angle grinder 180mm 7”

2. Cutting disk according to grinder ø115 x 1mm/ø4 ½” x 0.04” or ø125 x 1mm/ ø 5” x 0.04” Grinding disk 180mm

3. Drill

4. Welding machine

5. Tape measure, Caliper optional but useful for the correct marking of the cuts

6. Center punch ø10mm, Pen Scriber

7. Flat File

8. Clamps

9. Vice grips

10. Drill bits ø4mm ø8.5mm ø10mm ø16mm (ø8.5mm no needed if 11¹ exists)

11. Taps set M10x1.5mm

11¹. (or you can use M10 nuts 6pcs)¹


1. Angle iron 50x50x5mm about 2100mm

2. 2pcs Metal door hinge set ø20/10.5x80mm

3. 1pcs Plumbing pipe ½” about 500mm

4. 1pcs Plumbing Tee

5. 1pcs Round bar ø16x65mm

6. 2pcs Spring coil ø2mm 4~5 turns

7. 2pcs wide washers ø30x10.5mm for springs

8. 2pcs Bolts M10x50mm (or M10x60mm if 11¹ exists)

9. 4pcs Bolts M10x25mm

10. 4pcs Washers M10 (ø20/10.5) (or 8pcs if 11¹ exists)

11. For brake's bed I have use my hydraulic portable table

But you can use your welding table, or bench, a channel iron, or a rectangular tube.

Please note: the hypotenuse of the triangle of an angle-iron 50x50mm is 71mm.

So the width of bed must be >71mm.

A good choice for the bed material can be:

a Rectangular tube 80x40x3mm (5.37kg/m)

or a Channel iron UPE-80 (7.90kg/m)

or a Channel iron UPN-80 (8.64kg/m)

Also using a channel iron or a rectangular tube for bed, the brake can be mounted at a bench vise.

Step 2: Calculate the Desirable Full Width of Sheet Metal Brake

As long as we have collected all the needed materials, we will need to calculate the bender's and brake's length according the desirable maximum Full Width.

The "Bed Length" is equal to maximum "Full Width".
The "Bushing Base Width" is equal to width of "Angle Iron Side"

All the measures for cuts start from the edges,

so it doesn't matter the total length of the brake

Use the formulas below to calculate the desirable length for the bender and brake

Brake Length=Bed Lenght+(2*Bushing Base Width)
Bender Length=Bed Lenght+(2*30mm)


If Bed Length 805mm


Brake Length=805mm+(2*50mm)=905mm

Bender Length=805mm+(2*30mm)=865mm

30mm is the required space at each edge where would welded the pivots.

Step 3: Marking and Cutting

Remember Safety First.
If you are not familiar with metal working tools don’t try to reproduce this article
Welding Cutting and Grinding Tools are Dangerous!
Do it at your own Risk!
Use Always the Suitable Protective Equipment.

Cut the head from two hinge pivots, isn't needed.
Mark and then cut to length the pieces for the brake, bender, bushing bases and bed if you have go on channel iron or tube.

Mark the cuts on each of them measuring from edges.

All of the needed dimensions for the cuts, are described on the attached photos.

Use your grinder gently without any haste and be sure, that your cuts are perpendicular.

Step 4: Welding the Pivots to the Bender

The most important thing on a sheet metal brake is:

  • The axis of rotation center of bender to be inline to bending line.

Twist a steel wire ø1.2mm around the pivot and place it at the gap on edge of bender.

Adjust and do a tack weld at side of pivot and the top corner of angle-iron (point 1),

adjust the pivot again if needed, and do tacks next to the end of angle-iron (points 2,3).

Do the same at the opposite edge.

Check to see if the center axis of pivots and the top corner of angle are inline.

If yes: proceed to welding. If no: re-adjust

Q. Remove the wire or leave it in place?
A. It dosent matter Just weld.

Step 5: Assembling the Bushing Bases

To proceed assembling the bushing bases and bender to the brake's bed we will need to place temporarily, a sheet metal strip 0.50mm between bender and bed.

This strip will create the one half of the required space for the thickness of the bending material.

  • Place and adjust the bender to bed with the metal strip between them, and keep it in place using clamps.

  • Place the bushings to pivots.

  • Place and adjust the bushing bases to bed. Keep in place doing tacks to up/down side near the corners.

  • Do tacks to each set of bushing/base

Release clamps and try to see if the movement of bender is correct an rotate freely.(the metal strip now drops down)

If it's ok: proceed to welding. If not: readjust.

  • Drill the holes for screwing the bushing bases to bed.
  • Make threads at the holes to side of bed or use nuts.
  • In case that has used channel-iron or tube for the bed, do welds.

If you go on channel-iron or tube and bushing bases are welded, an oiling hole at bushings is required.(See attached photos)

Step 6: Placing and Setting Up the Brake - Checking the Release System

Using a flat file clean up the corner of angle-iron of brake where are the holes that passing the bolts, so as to creating a flat surface in where will be resting the bolts.

Place the brake onto the brake's bed.
Once again place the sheet metal strip 0.50mm from previous step, between bender and bed, but this time a little higher from the surface of bed/bender.

Place another piece from the same sheet metal strip 0.50mm vertically onto the bed and between the brake and the first one. Adjust the brake so as to be adjoined to metal strip tightly.

  • With this process we will create the second half of the required space for the thickness of the bending material.

Secure the brake with clamps.

Using a center punch 10mm mark the points that will become the holes.

Remove the brake and drill the holes starting with a ø4mm drill bit.

  • If you go threading do the holes ø8.5mm and then use a set M10x1.5 taps, for tapping.

In this case the needed bolts is M10x50mm (2pcs)

  • If you use nuts do the holes ø10mm and use M10 nuts (2pcs)

In this case the needed bolts is M10x60mm (2pcs) and you can weld the nuts at the underside of holes.

Screwing/Unscrewing the Brake to Checking the Release System.

For Release System we need 2pcs Spring coils ø2mm 4~5 turns and 2pcs washers ø30x10.5mm.

Step 7: Two Positions by 90° Removable Handle

For Handle we can use a Plumbing Tee and a piece of Plumbing Pipe ½” about 500mm with a ½” plumbing thread at one edge.

Has the advantage that can be mounted /dismounted, very quickly and operate at two positions, but has a very critical disadvantage: after some pressure the threads cracking next to Plumbing Tee.

But isn't so big deal and can easily modified and be strengthened, avoiding the cracks at the ending of threads.

We will need a drill bit ø16mm and a piece of round bar ø16x65mm to fix this problem.

Clamping the pipe to bench foot with a vise grip and clean the hole using an electric hand drill with ø16 drill bit.

Don't worry about how to ensure the 100% verticality position pipe/drill.
The inner hole diameter of pipe, is big enough so the drill bit can follow the correct direction of the original hole easily.

With the use of a center punch, do marks around the round bar and then press it, into the pipe.

Step 8: Sharpening the Brake's Edges (Clamping Bar) the Thought

The sheet metal brake is ready, has tested and is working,

but the bends isn't as sharp as I'll like.

Temporarily I decided to turn the brake by 135° so as to have more sharp bends,

and complete my BBQ, leaving the correct solution ( a brake with sharpen edges) for a later time.

It isn't something so simple and without a machining tool sounds impossible.

But I can do a try.

Both sides must be grinded simultaneously
Need a jig that can be able to keep the brake, stable and with no moves and big vibrations at the sharpening process.
Also I need a base or better a slide base where the grinder would slide easily,
so as to I be able to control the speed and the pressure.
One more thing that needs attention: the angle of the grinder disk and the touch at the two grinding areas

Step 9: Sharpening the Brake's Edges (Clamping Bar) the Jig

Mount the brake in a flat and stable metal surface (in my case I have use my hydraulic portable table using two pieces of angle-iron (e.g. 30x30mm or 35x35mm).
Be sure that the hypotenuse (BC) of the triangle (ABC) of your brake is absolute parallel with the surface of your base and do welds to keep it all in place.

Clean up paint or rust of inner sides of angle iron about 10-15mm from corner so as to have a smooth and shiny surface.

Paint with Aniline paint.

Wait for a while to dry.

Use a caliper or a vernier and mark a straight line at the entire length of the brake on both inner sides of angle-iron at 4mm from the corner.

What is Aniline paint?
Aniline paint is a very thin paint that used for clean and easy to view marks at metal treatment.
You can make it, using 400ml Alcohol, 50ml Shellac, 18ml Aniline and very good shake.

Place a square tube and lock it with clamps so to use it as slide-base for your grinder.

Place a flat bar 3mm thick on to the tube.

(don't use a bar thicker than 3mm, but you can use a combination of bars one over the other,

but the top bar must be a 3mm thick bar).

According to dimensions of your grinder the height of the slider (tube+flat bar 3mm) must be

so as the grinding disk to beabsolutely parallel to surface of base

and be adjacent to both sides of angle-iron.

The total height of grinding is 3mm but we need to make only 2.8mm leaving the rest 0.2mm for the final sharpening by file.

So when start the grinding, watch the lines, and be careful, to not exceed the limits.

Step 10: Sharpening the Brake's Edges (Clamping Bar) the Grinding

The use of a new unused 180mm grinding disk is required for best performance.

Start grinding sliding the grinder gently from one end to other.
At starting do not use any pressure on the grinder, let it work with its own weight, and then push it very gently and with the same pressure from one end to other.

If you are not sure that you can control your pressure just slide and let it to work alone. May be take little more time but we need a very good grinding without gaps.

Make pauses when you are on one end of angle to cool down, or use water to helping it stay cool.
After some passes and when the grinding sides, start to have different width or have already grind about 1.5mm of the height, remove the (3mm) flat bar and continue to slide the grinder direct up to the tube.

According to setup (main base, brake, and grinder slide-base) the grinding axis is parallel to main base.
The more grinding, the most offset of the grinding axis to downwards,
(the center is: on the point that the grinder handle,
be adjacent to the slider).

The side of angle that is closer to slider has less grind (or more height) from the far away side
But we need 3mm grind at the both sides.
Removing from the height of slider 3mmt (the flat bar), the grinding axis will move upwards.
Now have an opposite offset that be able to equate the grind on both sides.
When the grinding axis becomes parallel to main base, then the height will be the same at both sides of angle-iron.

Q. How can I understand that the grinding axis has becomes parallel to main base?
A. Watching the lines

The grinding has finished.

Using a flat file refine the last 0.2mm.

Pretty good straight and clear without any gaps
and the same width 6mm from one end to other at both sides.


Stainless steel AISI 430 at foul width 800mm 0.50mm - 0.60mm - 0.70mm

Stainless steel AISI 304 at foul width 800mm 0.60mm -0.70mm - 0.80mm

Galvanized steel at width 500mm 0.90mm

Thanks for your reading.
Good Luck if you try it.
Never say I can't do it.
Necessity is the mother of invention.


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6 years ago

This is an excellent and worthy project, something I have often needed.

However I would like to point out there has been no allowance made for different thickness materials.

At the moment it would bend very thin sheet but if a thicker sheet were attempted it would seize.

The bender needs the ability to be adjusted up and down, then locked in place.

This would then allow sufficient space between the bender and the brake when bending the sheet. Just like a normal sheet bending machine.


Reply 6 years ago

Really? Having gone through the Instructable there certainly is provision for different thicknesses of material and they can be clamped down. I like this version of a bending brake and will hopefully make it myself later this year. Thank you to 'kess_gr'.


Reply 6 years ago

Any thickness can be clamped down by the press, agreed, but when the bender is folding the sheet, there needs to be an equal distance (same as the material thickness, plus the inside bend radius, which is absolutely necessary of course) away from the brake for there to be room for the material to actually be there. The outside of the material will be against the bender and the inside of the material will be against the brake.

And if you look at any folding machine you will see this feature.

This also allows bends to be made with different bend radii.

So to sum up, the bender, in it's rest position (vertical), needs to be adjustable in and out to change the distance from the pivot (hinge) point.

This is plainly obvious to any engineer Really!



Reply 6 years ago

Thank you ItsGraGra for pointing this out. The fixed bending edge needs to be set back at least the thickness of the sheet goods or the brake will be 'sprung' when a fold is thrown. This design, with the vertical clamping, would result in the fixed edge being shoved rearwards, the knife edge possibly being swedged up and an inconsistent bend along the middle of the work. Some brake designs use a horizontal bolt adjustment to hold the fixed edge a set distance from the bending line.

Thank you Kevanf1, you have put a lot of good work into your construction and Instructable. Locking the clamping edge both verticaly and horozontaly will increase the consistency of your bends.


Reply 6 years ago

Ah, but I am plainly not 'any engineer' :D I'm afraid I have not looked at or even seen a press brake close up. So I thought this was fine as it was. I'll take a look at the You Tube video to see the modifications. I'll still be building one later this year :)


Reply 6 years ago

Hi ItsGraGra, Hi Kevanf1,

Thanks for your reading and commenting.

You can see some modifications about this brake in my YouTube video.

"Sheet Metal Bender Brake DIY Fully Modified" here is the link

I think that cover your needs. Soon I will make an Instructable with
these modifications.




6 years ago

well it look,s easy now to convert to std measures meament,s will be good Awesome Build thks again


Reply 6 years ago

Hi farmer53

Thanks for your reading and commenting.



6 years ago

Maybe you can get someone to help with translation, pretty hard to follow the text.
Good idea similar to one I built last summer. Mostly easy to follow pic's.
Keep up the good work.


Reply 6 years ago

Hi doctorlock,
Thanks a lot. Sure I have difficulties to translate.


6 years ago

I've been wanting to make one of these for a while but the thing that has put me off has been sharpening of the clamping bar's edges. You have shown me the way! Thank you :)


Reply 6 years ago

Hi throbscotte,

I am glad that my project is useful to you, and now you can restart.
You can see some modifications about this brake in my youtube video.
"Sheet Metal Bender Brake DIY Fully Modified" here is the link

Fruit Grower
Fruit Grower

6 years ago

Wonderful idea and awesome workmanship. Well thought out. Many thanks for doing this.


Reply 6 years ago

Hi Fruit Grower,

Thanks for your reading and your kind words.


6 years ago

This makes so much sense. If you can make it, do it. Great job!


Reply 6 years ago

Hi Wulframm,

Thanks a lot.


cycle ninja
cycle ninja

6 years ago

this guide is SOO much better than the one I was making. Excellent instructable, keep up the good work


Reply 6 years ago

Hi cycle ninja,
Thanks for your reading and your kind words.

DIY Hacks and How Tos

Nice. I always wanted a brake press in my workshop but I didn't want to shell out huge sums of money for a commercial one.