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.
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.
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.
This is a more complex tool that forms predetermined bends by clamping the workpiece between a matching punch and die.
wikipedia article: https://en.wikipedia.org/wiki/Brake_(sheet_metal_bending)
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
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
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
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.