Resistor Lead Forming Tool

If the appearance of your solderless breadboard is important to you, or you just have a lot of components to place, a lead forming tool is essential. Simply place a wire or resistor into the slots and apply pressure to the ends. It quickly makes perfectly centered leads at 90 degree angles.

These handy plastic tools are so popular, they are available in different sizes to form leads for different component widths.

Resistor bending tool

Resistor bending tool

I got to thinking, why not design my own and print it on a 3D printer? Imagine all of the customizations and improvements I can make! ← foreshadowing

My first attempt includes the following features:

Initial 3D printed jumper wire bending tool

Initial 3D printed jumper wire bending tool

The squared edges prevent fingers from being able to get in far enough to apply pressure to the leads. Oops.

Stacked edge prevents pinch pressure

Stacked edge prevents pinch pressure

No big deal. 3D printing is perfect for making design changes and prototyping.

Revised 3D printed jumper wire bending tool

Revised 3D printed jumper wire bending tool

Hmmm. I miss having a slot for resistors.

Revised 3D printed resistor bending tool

Revised 3D printed resistor bending tool

Not bad. See how that wire fits into the side grooves?

Slots and grooves for bending and forming small resistors

Slots and grooves for bending and forming small resistors

I admit that the resolution of the 3D printer is not fine enough to reproduce the numbers. Let’s make the numbers larger. And, let’s include larger widths on the bottom so that wires can reach the opposite bus on a solderless breadboard.

Large 3D printed resistor bending tool

Large 3D printed resistor bending tool

The numbers were darkened with an ultra fine point black Sharpie marker. As is consistent with me, I accidentally colored outside of the lines. I’ve cleaned up permanent marker before using acetone, so I used a tiny amount on a Q-tip. A shiny spot appeared because acetone melts ABS plastic. I decided to make the entire slot shiny, so I rubbed it down with acetone. It looks awful.

Fortunately, I can always print another one.

How It’s Made

The large resistor lead bending tool model is available at Tinkercad, as is the compact component bending tool.

The design is simply a long triangle with rods and rectangles cut out of it. (Hidden in the groove are the digits which are from Tinkercad’s font shape library.)

Resistor bending tool model

Resistor bending tool model

So, I guess I didn’t improve much on the classic design. But, I do have a base model now. In the event that I’m suddenly inspired (“I wish this had xyz”), I can quickly output a revision.