Bending and Forming Leads

Often, to make through-hole components fit properly on a board, you will have to bend the leads to get them to a manageable length. Usually doing this by hand is not an issue, but it also rarely looks professional, and it can be difficult to make components lay flat against the board this way. Or you may need to bend shorter leads on something like an IC or a transistor, which comes with its own challenges. Here are some best practices for bending or forming various component leads.

Resistors and Axial-Leaded Components

For parts with long leads, such as axial resistors, diodes, and capacitors, it is fairly easy to use a lead forming tool such as 1568-1132-ND to create 90° bend at specific lengths, pictured below.

2nd Picture from Lenore Edman’s article, “Five Electronics Tools You Might Not Know About” over at Evil Mad Scientist

If you don’t want to purchase a tool, it’s also possible to make your own with a spare prototype board and some generic header pins, similar to parts like SBBTH1508-1-ND and S1012EC-02-ND. Simply solder individual pins onto the board spaced apart for the desired length, and you have a makeshift lead bending tool.

Creating a Standoff

Occasionally it may be desirable to form leads in order to make sure that the component sits at a fixed height above the board, rather than sitting flat. A rounded curve or v-shaped kink along the lead can prevent it from being inserted past a certain point, and provide a bit of flexibility for resisting vibration and board flexing. This is commonly done with ceramic resistors and capacitors, which are brittle and may be damaged by these forces.

Again, while it is possible to form the leads by hand or with a set of pliers, this may be more time consuming or look less professional. There are specialized tools for creating a circular C-shaped bend (1691-1415-ND) or 30° angle V-shaped kinks in the lead (1691-1416-ND).

Transistors and ICs

With these parts, you have to be more careful when attempting to form the leads to avoid either breaking the leads or causing damage to the case of the component. It’s best to have at least a small pair of pliers or clamp to hold the lead in place and form it against. Another thing to keep in mind is that many of these components will have flat leads that should not be bent laterally, as this is far more likely to damage the case. Below is an example of what to avoid. Unfortunately we do not stock any tools specifically for forming this type of lead at this time, though there are some available on the market.