On Mon, 7 Aug 2006 15:56:42 +0100, Alan B. Pearce wrote:
> For fitting SMD parts to a PCB without using one of the little
> vacuum pickup tools, look for a pair of normally closed
> ("crossover") tweezers. If you attempt to use the normal style,
> your fingers will twist the tips and the component will go flying
> where you will not find it, but the crossover ones hold the
> component without effort on your part.

I've actually found the opposite. I build lots of SMD prototypes and
have quite a few high quality stainless steel tweezers. I have
regular and "crossover" types and find that a properly designed and
sized regular type is easier to use for placing SMD parts. A properly
designed tweezer will not require too light a touch and won't let you
easily "over grip" the part and twist the tip. I can't remember the
last time I had a part go shooting off into space with the regular
tweezers.

I find crossover tweezers to be more problematic as the tweezer
itself supplies the gripping force and any amount of squeezing you
apply to the handle while handling the part reduces it. You are
relying on the tweezer to apply the correct gripping force which I
have found varies a lot between component types. For me, it means I
accidently drop parts from time to time because the tweezer doesn't
apply much extra gripping force to the part to begin with and a
little pressure from my grip is all that's required to "release" it.
I find that extremely frustrating.

But like all tools, it's a personal preference thing. Whatever works
best for you is the best tool for the job in the end.

Matt Pobursky
Maximum Performance Systems


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