# PTH drill diameter do the IPC take the pin distance in account?

I wonder if the IPC take the Pin distance tolerance in account for the drill diameter? (see p in pic). I can't find any guidelines for it anywhere.

Or is it just so that it's implicitly,common sense that the drill diameter shall be: pin tolerance distance + maximum pin diamter = minimum drill diameter?

That is what I would assume if there isn't any guidelines in any IPC?

This is an indirect reference to the actual (for pay) IPC documents, but it appears it does not take pitch tolerances into account.

Minimum Hole Size is calculated according to equations below:

Minimum Hole Size = Maximum Lead Diameter + 0.25mm (for Level A of IPC-2222)
Minimum Hole Size = Maximum Lead Diameter + 0.20mm (for Level B of IPC-2222)
Minimum Hole Size = Maximum Lead Diameter + 0.15mm (for Level C of IPC-2222)


There is some compliance in the leads even close to the body, and the ends are certainly not guaranteed to not be bent a bit, so it's not as important as you might think.

• Yes I've seen it and I also have access to latest IPC-2222. However as you say it doesn't seem to take the pitch tolerances in account. Which I believe may be a problem for some radial components with thick leads that don't bend easy. – Anton Ingemarson Sep 25 '17 at 7:35

IPC std is 0.2mm drill size over lead size +/-0.05mm depending on 3 classes of part and process.

http://www.ipc.org/committee/drafts/1-13_d_7251WD1.pdf

• Hi Tony, I'm unable to find what you refer to, could you please refer more precise? In the referenced standard I can only find "20%" and "5%" tolerances under section "3.4.2.1 Solder Paste Stencil" and "7.4.1 Wave Soldering" which don't have anything to do with the pitch and dimension tolerances, what I can see. – Anton Ingemarson Sep 25 '17 at 7:47
• Is this for manual or auto-insertion? – Tony Stewart EE75 Sep 25 '17 at 12:42
• The components is manually placed/inserted on the PCB before wave soldering. – Anton Ingemarson Sep 26 '17 at 11:04