Building Prototypes Part 4 of 18 Bending

Press-Brake Techniques and Modifications

The presenter demonstrates press-brake techniques and modifications for making prototype parts and brackets.

Setup and Correcting Bends

The brake uses a digital caliper or manual gauge to position the work. Bending hardens metal, so simply opening a bend will not restore it to flat. To correct a bend, anneal the metal by heating it until it glows red before straightening. Otherwise, substantial force may be needed, and marks may remain.

Tooling for Channels

A gooseneck punch provides clearance for narrow channels that a standard V-shaped punch may obstruct. A punch with a hole can form deeper U-shaped channels.

The presenter suggests buying a long tool bar and waterjet-cutting it into useful lengths, with a few custom pieces as needed.

Alignment Table

A marked table helps position narrow strips accurately, especially when they provide little surface area for alignment.

Capacity and Die Choice

Bending capacity depends on material thickness, bend length, and die opening. This 25-ton brake can bend about 12-gauge steel—just under 3 mm—across its full width. A wider V-die permits thicker material.

A roughly ¾-inch opening is presented as a useful general-purpose choice. Narrow sections can allow thicker stock, and aluminum can be bent more readily than steel.

Adjusting Bend Angle and Radius

An air valve at the front of the machine lets the operator limit the stroke to make angles less than 90°, avoiding adjustments at the rear.

For rounded bends, scrap material can be used to form a radius tool. Magnets help hold the radius tooling in place.

Improving Narrow Bends

A sliding-finger modification lets the operator use a narrow finger for tight bends while retaining a larger support area for positioning the part.

Making Stronger Brackets

The presenter demonstrates three approaches:

1. Spot-weld a simple bent bracket, checking it against a square.
2. Add a bent triangular stiffener and spot-weld it.
3. Form a reinforcing rib in the bracket using a rounded, hardened-steel blade. The rib substantially increases stiffness.

Source

The presenter and instructor is from Dan Gelbart’s channel. A brief off-camera questioner asks about the tool with a hole.