Through Hole Clearances

[ryandias]

Where could I look for the PCB through hole diameter vs lead size?

is there an IPC standard? I have searched a couple with nothing regarding this topic. Closest I've seen was land sizing

 

[itsmoked]

You don't need no stink-king book.

You just look at your lead diameters and add a few mil, about 5 for plate thru error, and about 5-8 for solderablility. Then you try to reduce the number of drill sizes used by re-using a larger already required size for various smaller leads as long as you don't go way over.

Keith Cress
Flamin Systems, Inc.-

http://www.flaminsystems.com

 

[MacGyverS2000]

I typically go with +20 mils and be done with it...

Dan - Owner

http://www.Hi-TecDesigns.com

 

[blcpro]

I've found that a tight-fit works nicely for hand-soldering, so I'd agree with itsmoked.

 

[Comcokid]

For years, I've used lead diameter + 10 mils = hole diameter. Then adjust the odd-sized leads up or down slightly, if there is a hole size close, to minimize the number of different drills.

 

[Warpspeed]

I too have used component lead diameter +10 thou .01" with great success.

 

[ryandias]

problem being that we have to design for machine assembly. not Hand assembly. I assume the machines are not as good as me. Hopefully! haha

 

[Comcokid]

Hole clearance for machine insertion - I've still used lead diameter + 10 mils = hole diameter. However, for this I've generally try not to round-down when finalizing holes sizes. Been a while since desgining thru-hole for machine insertion. But I seem to recall that most machines had a 'general' design guideline that could be followed.

Suggested hole parameters may also be different when the substrate is a CEM1 or PC-75 'appliance type' material where the holes are usually punched rather than drilled.