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Topic: tool to make J-lead from a DIP? (Read 904 times) previous topic - next topic

kg4wsv

I've become a fan of SMT, since when I etch boards at home it means I don't have to drill holes.

The J-lead SMT package is more or less a DIP package with the legs curled under it, like a dead spider.  Does anyone know of a tool/jig/fixture that would allow me to form J-leads on a DIP IC?  I've googled, but have not found such an animal.

-j


Oracle

I don't know the J-lead package, but from your description, can't you just get a flat glass block and roll the IC so the leads are wrapped tightly to the chip body?  

Sort of the way you bend the pins of a new chip in a bit so they'll fit in a socket, but bent much farther.

macegr

#2
Oct 15, 2008, 01:21 am Last Edit: Oct 15, 2008, 01:35 am by macegr Reason: 1
You can lay a small metal rod, like a small screwdriver shaft, along the inside of the pin row and then bend everything over by hand or using a flat point screwdriver. However, I almost never do this because I either buy surface mount chips, or resign myself to drilling holes.

Here's one I did just now, using a small drill bit and a screwdriver:
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kg4wsv

Quote
can't you just get a flat glass block and roll the IC so the leads are wrapped tightly to the chip body?

Nope, they'll just fold flat at the point where the lead steps down to the narrow section unless you have something to form them around. The chip I measured would short the opposing pins together if they folded flat.

My idea was along the lines of macegr's.  I visited our machine shop for ideas and left with a mandrel for a .300 wide DIP that forms the leads bent about half the radius that macegr did by hand as shown in the previous post.  It works great for forming the leads, but the resulting lead seems long, not sure what it will be like once I solder it.

I may try to splay the leads out, gull-wing style, and see how big the footprint will be.

thanks guys, keep the ideas coming.

-j


macegr

I've also seen DIPs where the skinny part of the leads were just sheared off, and the fat part soldered to the PCB. It looks like a normal through-hole installation except there's no holes. The hard part would be shearing them all at the same length, any difference will make soldering difficult.
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dcb

you can splay the leads outward too, instead of under.  might make soldering a little safer with the heat applied away from the chip.

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