Eagle pad size recommendations

[EnnPeeEff]

Hello,
I got back some PCBs that I designed using the GM Eagle parts library, the component pads are a little small and I find them difficult to solder.  I understand how to change the pad sizes, I just don't know what to change them to.  For instance, BYOC PCBs have always been very easy to work with.

Opening up a 1/4 watt resistor (for example) in the editor, the drill size is 0.02755906 which is fine, and the pad size is set to auto.  It seems like that amounts to the pad being 0.046 diameter.  If I change it to 0.05 it's a slight increase.

So my question is, what's a nice comfy pad diameter for components like 1/4 watt resistors, panansonic chicklet caps, etc?

Thanks!

[aion]

When I first started, I went through the GM libraries and changed every pad to 0.07 diameter. (I recommend editing the libraries rather than just using restring - that way it's a global setting and not just a per-project setting.) This has been the perfect size for me. For resistors, capacitors and diodes, I bumped up the drill size to 0.031(...) but kept it at the 0.027 for ICs and transistors.

For resistors, especially if you want to use the 0.3" spacing, it's nice to have the extra hole size so you can fit resistors with thicker leads without having to use needle-nose pliers to get them bent as close to the body as possible.

[EnnPeeEff]

Thanks,

I've been messing around with the libraries.  I tend to use the same parts over and over so getting them right as a global parameter is definitely the way to go.  Right now I have things set at 0.086 which looks a little big on screen, it's hard to tell how it would feel to solder to that in real life.  Thanks for the drill size tip.

[davent]

I use 75mil for most pads.

[PRR]

Are you asking on multiple forums?

Yesterday on a very similar question, my opinion was that 0.050" may be OK for factories making small gear, but for my-eye DIY _I_ want a pad I can see and hit. 0.1" is small. 0.2" is better.

Your overall size will usually be set by parts, not pads. Blow-up the pads until they don't quite touch each other. There's no DIY reason to keep them so teeny. (In mass production, large pads mean more heat and more solder. But in DIY it is better to have easier-to-do size pads.)

[EnnPeeEff]

PRR, yup.  I didn't know you were over here as well, nice to see you.

On a TO-92 transistor or electrolytic cap with 2.5 mm lead spacing, it looks on my computer screen like .086 pads are about as big as I can go without worrying about solder bridges.

[PRR]

TO92 leads bend. Center lead bent out is even a standard option; easily DIY-ed if you only have inline lead parts.

With center leg bent, 0.150 pads fit fine.

Yes, the part may be 0.3" and the total pad width is 0.45"; also wider the other way. You can't make a mini cell-phone this way. But you can make most of the 2- and 3-transistor effects and still fit a small box.

[TooManyKnobs]

For DIY stuff I haven't moved beyond perforated but at my day job I've had great results using the IPC-7351 land pattern calculator you can download for free from IPC. Using the most material condition setting.

-Adam