Is this OK? (lead bending)

[Speakerguy]

I never bend leads on IC's right at the package, but on resistors I frequently just bend the leads right at the device, so your standard 1/4W resistors fit just fine into 300mil spaced holes.

I've never had a problem with it, but is that 'kosher'? Or should I use a lead bender and 400mil spaced holes? I'm thinking in terms of what would or wouldn't fly in a production environment, where reliability is critical. Thanks!

 

[Hero999]

I suppose you're not supposed to do it as it puts additional stress on the leads.

If you want you could save space by mounting them radially but it seems to have gone out of fashion, probably because it won't stand up so well to vibration.

 

[Dean Huster]

I use a plastic component lead bender, available inexpensively from many hobbyist sources. It insures standard-center bends. I always bend my 1/4-watt resistors to 0.4" centers. Bending them to 0.3" (right at the body) does stress the leads and does not provide you with much of a place to hook a scope probe for testing or troubleshooting. I've found that the extra 0.1" did not impact design size hardly at all and in fact left some greater variety in spanning distances underneath the board. You can still bend to 0.3" or 0.45 or 0.50 inches for special cases. I do bend signal diodes to 0.3" and 1N4xxx rectifiers to 0.4". At least you developed and adhered to a standard. It's amazing how many hobbyists just lay their boards out without regard to lead length and end up with a final project that just doesn't look very neat. I've always been a neat-freak with board layout and panel design so that I'll always be proud of my projects.

Dean

 

[Nigel Goodwin]

I've always been a neat-freak with board layout and panel design so that I'll always be proud of my projects.

Do you put all your resistors the same way round as well?, I do!

 

[Speakerguy]

I actually do that with electrolytics, Nigel Quick look to make sure all the stripes point the same way makes sure none of them goes kaboom when I hook it up.

I've already got both sizes of lead benders from Mouser, as I was going to use them whenever I used larger spacing for a single part on a board (like using a resistor also as a jumper). I just wondered if my old bend 'em at the resistor method was ok. I didn't think it was, but the group consensus has me certain .4" is the way to go. Hadn't even thought about the ease of clipping on the lead, that alone is a good reason to do it.

Thanks!

 

[Dean Huster]

As I coincidentally just commented in the "square pad" thread, Nigel, you bet I do. After working for Tektronix for several years, I adopted their standards of board layout. All resistors lay with their tolerance bands pointing to the same edge of the board. It's subtle, but the board looks nicer when completed and it's also easier to read the values at a glance. Of course, most companies used automatic insertion equipment and that's why their resistors always landed the same direction.

With caps and diodes, I try to keep things the same direction but am willing to wander a bit there. For instance, a bridge rectifier is never laid out in a "diamond" textbook pattern, but always as four diodes laying parallel to each other, either in a line or in a rectangle shape.

I also install and label test points at critical areas to aid in troubleshooting and calibration. Tek did that because a scope or meter probe hooked to a component lead every six months for a calibration will eventually do damage. I also make sure that I have a good, solid ground test point available.

Dean