Printed Circuit Board Design

[kb5urq]

I was curious if any of you PCB wizards out there could give me some guidance on how to know what thru hole diameter to use given the diameter of the wire's conductor.

I'd like to bring some wires into a PCB and solder them directly into the thru-holes. #I do have a chart which shows the maximum diameter for each size wire. #I'm sure there is some IPC standard out there that tells you what kind of margin you need for a given guage wire.

Just wanted to get some ideas from here as to what values are used in practice.

Jason
KB5URQ

[wb7dmx]

I think that the only time the hole dia. is critical is when your planing on through hole plating.

for the size hole for any given wire, if the wire fits through the hole, is big enough.
there is standard drill bits for pc boards.

Ocean state electronics sell a PC board drill kit with the standard sizes. check there web sight on line listing.

[AG3Y]

A micrometer or high quality vernier calipers would be handy. You wouldn't even have to know what size bit you are using. Just mic the wire, select a bit that is just a wee bit larger and won't quite fit through the jaws of the mic, and you have your size !

I have even made a makeshift drill bit out of the wire being used for the component leads themselves! It works, but you don't get more than a few holes before having to replace the "bit"! A Dremel™ rotary tool held in a press is the best item to use for drilling those holes.

Hope this helps! 73, Jim

[KC7YPJ]

39.95 tabletop drill press from harbor frieght, whatever size drillbit that will leave a big enough hole for your wires.
a spendy caliper is nice and all (own 4 along with an asortment of micrometers) but in all honesty in the 5 years since I bought this elcheapo digital caliper for 19.99 I haven't ever ran into anything that mandated digging out the quality tools, it's accurate enough to turn a bronzed (farmers fix) axle shaft back to oe diameter and your only out 20 bucks if it gets sacrificed to the tool gods, for such a cheap price it's right near the top of my list of most bang for the buck purchases.
edit (think harbor frieght or your local checker/schucks/kragen, pep boys, auto zone or the like have em as well)
on a side note anyone have a line on a good place to buy ferric chloride?
that and have any suggestions for making pcb transfers with a printer, this print- trace-retrace from a vague outline- fill process is getting old and I haven't kept up on the latest print/stick/etch advancements.

[wb7dmx]

Quote[/b] (KC7YPJ @ Dec. 29 2007,03:26)]39.95 tabletop drill press from harbor frieght, whatever size drillbit that will leave a big enough hole for your wires.
a spendy caliper is nice and all (own 4 along with an asortment of micrometers) but in all honesty in the 5 years since I bought this elcheapo digital caliper for 19.99 I haven't ever ran into anything that mandated digging out the quality tools, it's accurate enough to turn a bronzed (farmers fix) axle shaft back to oe diameter and your only out 20 bucks if it gets sacrificed to the tool gods, for such a cheap price it's right near the top of my list of most bang for the buck purchases.
edit (think harbor frieght or your local checker/schucks/kragen, pep boys, auto zone or the like have em as well)
on a side note anyone have a line on a good place to buy ferric chloride?
that and have any suggestions for making pcb transfers with a printer, this print- trace-retrace from a vague outline- fill process is getting old and I haven't kept up on the latest print/stick/etch advancements.
Ocean state electronics has all material for making PC boards

[K8ERV]

I never tried using a component lead as a drill, but small nails work. Cheap too--

TOM K8ERV Montrose Colo

[AG3Y]

You're right, Tom. Brads ! http://www.qrz.com/iB_html/non-cgi/emoticons/wink.gif

[N9SX]

We do PCBs here all the time and the rule of thumb we use for hole sizing is 0.018" over the lead or wire size. We may go between 0.015" and 0.020" (nominal) oversize, depending upon the circumstances; but 0.018" is our target. This allows enough space to insert the lead/wire and for solder wicking into the hole during soldering.

And just an FYI - Typical plated through-hole tolerance is 0.003" for most manufacturers. This allows for the fact that only discrete drill sizes are available and for the variation in plating thickness.

Eric
N9SX

[K8ERV]

Quote[/b] (AG3Y @ Dec. 30 2007,11:57)]You're right, Tom. #Brads ! #http://www.qrz.com/iB_html/non-cgi/emoticons/wink.gif
I'm always right, just sometimes more righter than others!

On the hole size, Abe had it right. A man's legs should be just long enuff to reach from his body to the ground. Same goes for wire holes--

TOM K8ERV Montrose Colo

[AG3Y]

I just came back from the hobby shop, and found a set of ultra-small drill bits that have the conventional shaft for Dremel™ type rotary tools. There are bits and rasps that would make a snug hole for 32 gauge wire, on up to the equivilent of the smallest conventional bits !

You can check out the website of the supplier of these bits. It's:

http://www.harborfreight.com

Note: this is not a "paid commercial announcement"

http://www.qrz.com/iB_html/non-cgi/emoticons/biggrin.gif

73, Jim

[KI6NNO]

Radio Shack still sells ferric chloride in pint bottles - I haven't seen the stuff in all stores; the one by me in a strip mall has it, so does Fry's in City of Industry, CA - I'm guessing the rest of them do too.