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Looking at a printed circuit board (PCB), ever wonder how they bend every one of those resistor leads perfectly every time? Depending on how many PCB’s are in a production run, you’d use different tools.  For a run of one or two boards, you could always try a pair of pliers and a keen eye, or you could use a plastic lead former. If you’re running a ton of boards at once, a better solution would be a lead forming machine from a company like PEI.

Slots for radial lead resistors run along the length of the high impact ABS plastic former. Each slot is .05″ longer than the next and has radiused edges to make perfect bends without stressing the leads. It can be used to bend the leads of 1/2 watt resistors, 1/4 watt resistors, and diodes.

The lead forming machines, on the other hand, can take a strip of taped axial components and spit out components ready to be stuffed onto a PCB board. The machines cut the leads and bend them to a variety of different shapes depending on what you need. They can be motorized or hand-powered to save some dough.

Pricing for the plastic lead former starts at $5 before shipping. If you don’t have a PCB stuffing house, you probably can’t afford a PEI lead forming machine — if you do run a production house you can’t afford not to have a tool like it.

Lead Forming Tool [Jameco]
Lead Forming Tool [Wassco]
Lead Forming Tool [Evil Mad Scientist]
Axial Machines [Olamef]


14 Responses to Resistor Lead Bending Tools

  1. Toolhearty says:

    Thumbs up to the cheap red plastic one on the left. That’s all I’ve ever used for assembling small quantities of pcbs (back when resistors had leads, that is).

  2. Toolhearty says:

    …make that “on the right”.

  3. stuck in the 70s says:

    Man what a flashback I havn’t used these in production for a few decades. most stuff is done with smt (surface mount technologies) these days. but I guess you still see some through hole stuff around.

  4. fred says:

    Since this tool seems to have been eclipsed by changes in technology in the electronics business – I recently saw it being marketed to model railroad hobbyists:


  5. @stuck in the 70s:

    It’s funny, when I was in college in the 90’s they never even mentioned surface mount technology, or course you’d seen it if you’d ever taken anything recent apart, then when I got my first job I was thrown into a world that was all surface mount.

    Even in the the early 00’s there were a few high wattage resistors we used in some of our products that some of my fellow engineers swore just wouldn’t work if they were surface mount.

    That said, through-hole technology is alive and well, take apart a smoke detector or a CF light-bulb sometime, probably still in colleges too.

  6. @fred:

    I think the plastic forming tool has a niche market in the DIY and prototyping business. It’s still much easier to breadboard with through hole components — although it is possible to prototype with surface mount, it just takes more creativity.

  7. Eli says:

    We sell resistors individually where I work, but we buy them on tape and reel. We have a machine that looks similar that cuts them off of the tape.

  8. Chris W says:

    I have built lots of PC boards, including a Heathkit color TV. I never used a bending jig and never had a part break, and the Heathkit is still in daily use 35 years later. Today, some resistors are barely visible!

  9. Stan says:

    @ Chris W,

    Heathkit…. Aw the good ole days. I put together my fair share of Heathkits. I remember helping my father back in the 60’s make a Organ. We also did a few radios, and stereo stuff. Them and Allied Radio…….
    As far as resistors & cap’s never used one of those new fangled bender thingies, just a needle nose and my fingers.

  10. Larry says:

    There was also a tool similar to a calipers. One part of the jaws was a pair of pins used to measure the distance between the holes. The other part of the caliper jaws were round posts to bend the resister leads around. I haven’t seen one of these for at least 30 years.

  11. James says:

    I work in the industry and have “thru hole” auto insertion equipment the Smithsonian would fight for. One of the programs still active we “sand” carbon resistors to dial in the needed resistance for the B-52.

    We have a C-130 program that uses oil impregnated caps on some power supply boards

  12. Wayne D. says:

    Through hole is alive and well in the aerospace industry. They are still around due to the amount of time needed to verify a new design. Why design something new when the old one has worked reliably for the last 50 years and the parts are still around? The military doesn’t change their cars until they have to because of the time. Just look how long it takes the military to figure out which plane they want to use for the new tanker.

  13. Tim B. says:

    Being an EE for a large electronics manufacturer, I can definitely say that thru-hole is most definitely still around and in use! Perhaps not nearly as much for final end-item products, but most definitely for prototyping. Even when prototyping with newer type chips, etc, it is still easier to adapt the chip to the breadboard than to adapt your prototyping method to SMT/SMD… we save that until as late as possible. Of course, with alot of newer technologies, breadboard method cannot work for prototyping (especially when higher frequency work is involved)..

    So, all that said, I actually of one of the type on the left, and 3 different scales of the one on the right in my workbench drawer at work, and they most definitely see use =) (The ones on the right more-so, just because small quantities… the left-hand ones are more for production use.)

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