DIY Sheet Metal Bender Brake Fully Modified

Introduction: DIY Sheet Metal Bender Brake Fully Modified

About: DIY, HomeMade Tools, Builds, Repairs.

At a previous instructable, we had seen the build of a simple version, Sheet Metal Brake.

The brake works pretty good but, has some limitations.

The thickness of bending material can't be over 1mm.

Has difficulty at bends that is too close to edge (e.g. 5mm).

To lock/release the brake needs a wrench, but it is trouble when drops down.

So I decided to modify my sheet metal brake and update my design into a new, stiffer and more stable, with more possibilities.

Additions / modifications

A truss to bender (to avoid distortions and increases the force at the center)

Another truss (with two adjustable members) at clamping bar

Thickness Adjusters

Quick lock/release Brake

Change/upgrade M10 to M12 bolts

Tightening Bolt Slide Guides

Stud bolts, for using when need to bend a box

Step 1: Tools and Materials


Angle grinder 115 or 125mm

Cutting disk ø115 x 1mm - ø4 ½” x 0.04” or ø125 x 1mm - ø 5” x 0.04”


Welding machine

Ring Roller Bender if any, or you can go straight line truss

Tape measure, Vernier

Center punch

Pen Scriber

Flat, Square, Round Files


Vice grips

Drill bits: ø3mm, ø4mm, ø6mm, ø8mm, ø10mm, ø12mm


Round Bar ø12mm including the loss in size at bending 2500mm

Flat Bar 40x5mm about 60mm

Angle Iron 30x30x3mm about 2pcs x17mm

Stainless Steel Round Bar ø6mm 2pcs x90mm

Stainless Steel Round Bar ø3mm 2pcs x16mm (or in turn you can use ø3 nails)

M10 Bolts x60mm Full Treaded 2pcs

M10 Nuts 6pcs

M10 Long Nuts (30mm) 2pcs

M12 Bolts x60mm 2pcs

M12 Long Nuts (36mm) 2pcs

M12 Nuts 6pcs

M12 Washers 6pcs

M12x120mm Metallic Anchors 2pcs

M12x220mm Stud Bolt 2pcs

Step 2: Bender Truss

Remember Safety First.

Welding Cutting and Grinding Tools are Dangerous!

Do it at your own Risk!

Use Always the Suitable Protective Equipment.

At first, I needed two arcs, made of ø12mm Round bar.

(one for bender and one for brake)

But I had no such tool, so decided to make one.

For the bender truss need an arc as follow

Width of arc 710mm

Height of arc 65mm

Length of arc 726mm

You can calculate your arc using The Complete Circular Arc Calculator from

I don’t know why, but had stuck on my mind, to make curved trusses instead of straight line that are stiffer, perhaps from the challenge: to complete the tool, I need to build another tool.

Also need a member (45x45mm) that joins the center of arc with the middle of chord (bender).

I made it, using for that, two pieces from flat bar 40x5mm.

Step 3: Clamping Bar, Tightening Bolt Slide Guides & Truss

Using a piece of round bar weld the two holes at the side of brake that I had do, when temporarily decided to turn the brake by 135° for sharpen bends. (See step 8 of previous instructable,)

Place a M10 bolt at tightening hole.

Using two nuts adjust/secure the bolt so to be on the square to the top corner & to the hypotenuse of the triangle, of angle iron

Use a sheet metal strip to protect the thread from splatters.
Weld the nut at both inner sides of angle iron and remove the bolt.

Using a ø10 drill bit, drill the nuts,

the bore direction, must be from the top corner of angle iron to downwards (the existing ø10 hole is a good guide).

The Tightening bolt slide guide, is ready, but need a second pass using an ø12 drill bit.

Prepare the clamping bar to install the truss.

At the top corner of clamping bar find the center and then, do marks left/right of it, at 100mm distance.

Drill holes ø12mm.

Using a flat file clean up the corner of angle-iron so as to create a flat surface in where will rest the nut of the adjustable members of truss.

For the brake need an arc as follow
Width of arc 800mm

Height of arc 120mm

Length of arc 847mm

Also need two members that join the arc with the bottom chord (brake).

For members have use M12x120mm Metallic Anchors

Once again at the top corner of clamping bar, do marks left/right of center at 400mm distance.

Place the arc and the brake on a flat surface, adjust and then mark the points of the cuts.

Make a groove at the down side of the ends of arc so to suit to top corner of angle iron firmly. Do tack welds, place the members and adjust the verticality, tack welds.

Check if everything is ok.

If yes, proceed to welding.

If no, readjust.

Step 4: Thickness Adjuster

For the thickness adjuster we will need

2pcs bolts M10x60mm full threaded

4pcs regular nuts M10

2pcs long nuts (30mm) M10

2pcs angle iron 30x30x3mm

2pcs stainless steel rod ø3x16mm (or in turn ø3 nails)

At the bushing base, there is already a hole that used to tightening the brake

It is fixed, with a standard distance from the bending line, limiting the possibilities of the tool.

But our needs vary, according to thickness of the materials, and the brake must be able to move in/out.

To correcting this problem, a hole at obround shape 12x24mm is required.

Find the center of the existing hole at the bushing base, and do a center punch mark, at 12mm distance to back.

Start drilling, with the use of an ø4mm drill bit, then with ø10mm, and after then with ø12mm.

Using a round, a flat and a square file, accomplish the treatment of obround shape.

Screw two nuts at M10x60mm full threaded bolts and secure it in a stable place using a vice grip, at the middle nut. Do a center punch mark about 5mm from the free edge of bolt (or at the third female thread).

Do an ø3mm hole.

Cut two pieces 17mm from an angle iron. 30x30x3mm.

Place the first piece of angle iron at vise.

Mount [bolt - nut - long nut - nut].

Adapt to the angle iron using a vice grip (last nut/angle iron). (See attached photos)

Weld the nut at angle iron - unscrew - let it cool.

Secure it, and clean the nut threads using an ø10mm drill bit.

Grind the welds and the nut's corners, so as to be round.

Place the ø3x16mm pins into the hole at bolts.

The adjusters are almost ready.

Place the clamping bar at the zero point, secure with bolts, do the necessarily marks for drilling and cutting at the bushing bases.

For all measures/dimensions see the attached photos.

Remove the clamping bar.

Drill the holes.

Make the cuts for the needed gaps.

Square the round corners of the gap using the square file.

Refine the gap so to be 17mm.

Place the adjusters into the gaps.

The center of long nuts must be a little higher (about 2mm) of the level (bushing bases/bed/bender).

If the width of gap is 17mm then the center of the adjuster is 2mm higher of the above level.

Adjust and then weld.

Thickness Adjusters are ready made.

Step 5: Quick Lock and Release Stud Bolts

For the quick lock and release we will need

2pcs M12 Long Nuts (36mm)

2pcs M12 Washers

2pcs M12 Bolts x60mm

2pcs Stainless Steel Round Bar ø6mmx90mm

Do a center punch mark, at one of six sides of the nut, at 8mm distance from the edge.

Drill an ø6mm hole, and pass through the Stainless Steel rod.

Hammer the corner of both edges of the rod to downwards, so to can't pass from the hole.

Place the M12 Bolts x60mm at bushing base, from the down side. Weld a
piece of steel at bushing base, parallel to the side of bolt's head, so the bolt to can move in/out but cannot be rotated.

Stud bolts - Box Bends

2pcs M12x220mm Stud Bolt

6pcs M12 Nuts

4pcs M12 Washers

This type of sheet metal brakes are usually for straight bends.

But we can use some cheats and bend boxes.

If your basic needs are for box bends, isn't the suitable tool. You need a Box-and-pan brake.

You can see how to bend box with this brake at this video

Testing the brake

All jobs completed

Lets do a small test

Material: galvanized shett metal at thikness 0.90

Bend: at 5mm from the edge

You can view the video of the test here

Also you can see this brake converted to bench vise mount 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.


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    4 Discussions

    The other Finnish guy

    Looks that we have ended nearly similar result with the thickness/radius adjustment. My result was to make upper part moving. :)


    Reply 3 years ago

    Hi Tuomas Soikkeli

    I have seen your project at
    In few words, it is the same adjuster, with similar results.
    The only difference it was "the how to" of our initial thought.

    The other Finnish guy
    The other Finnish guy

    Reply 3 years ago

    Yep. Its nice to see how same things can be seen / made different ways. :)


    3 years ago

    Considering the forces ,straight pieces to each upright would be firmer than a rounded bar or just a 2x 1/4 bar welded along the top