[Elecraft]Bending component wires

[Ron D'Eau Claire]

I believe you misunderstood me, David. I was not suggesting that one should
bend "...the wires of axial components against the component Body..."
assuming you meant bending the leads sharply at right angles against the
body.  

I hold the component in my hand and press down on the end of the lead with
my finger until the lead extends away at right angles to the component body,
allowing the lead to form a smooth curve that occurs naturally where it
leaves the body. 

All components with leads are designed for that sort of handling without
damage. In my experience, that produces lead spacings that normally drop
right into the pcb holes. I was observing that I have not found it necessary
to use various tools to wrap the lead around in order to get the right
radius bend in the lead where it exits the part body. 

I avoid using pliers to make sharper bends, especially right-angle bends in
leads, unless absolutely necessary. Sharp bends, especially a tight,
right-angle bend does stress the lead that can cause the metal to
crystallize at the bend. If such a drastic bend were needed, I'd use pliers
and definitely would not bend the lead against the part body either.  

In general I avoid forming leads with pliers and other tools as much as
possible. Tools like needle-nose pliers provide a huge amount of leverage
and it's very easy to accidentally apply more pressure on the lead than one
intended, damaging the part. With modern epoxy coatings, a good clue is
whether your technique causes cracking of the epoxy around the lead. It
should not. That said, cracking the epoxy around a lead does *not* mean the
part is damaged. On most parts no harm is done: it's just a warning to be
more careful. However, some parts are very tender. The small chokes that a
number of builders have had trouble with are a good example. The very fine
wire used on the choke winding itself is attached to the much larger
component lead just inside the epoxy coating at each end. The leads are very
securely attached to the body of the choke, so it is easy to bend the lead
too sharply when using pliers, cracking the epoxy and breaking the
connection to the fine wire just inside with almost no external clue that
any damage was done. It's all a matter of which way the lead was bent
relative to where the lead connects inside. If the builder is lucky and
happens to bend the lead toward the connection inside, it'll probably
survive. If it's bent the other way the lead will pull the fine wire and
it'll break easily, ruining the part.

Ron AC7AC 



-----Original Message-----

I advise against bending the wires of axial components against the component

body; this can lead to stress fractures at the joint depending how much 
force you use.   I use fine needle nose pliers to hold the component wire 
near the body, then bend the wire sharp against the pliers.  It's a small 
but easy and consistent way to avoid a stress failure which might take a 
while to appear.  Having said this, modern components *may* not be 
susceptible to this failure mode: I'm just in the habit these 50 years.

I remember a colleague clipping wires near me and one flew into a power 
supply I was working on causing a large flash and bang right under my nose. 
A salutary lesson to all.

David
G3UNA