Sorry for the confusion.  I just discovered that this problem was corrected
in IPC-2221 Amendment 1

Bill

>  -----Original Message-----
> From:         Dieffenbacher, William C
> Sent: Thursday, May 11, 2000 9:35 PM
> To:   [log in to unmask]
> Subject:      Plated Hole Pad Dimensions
>
> Can someone please explain why the internal pad size is calculated (per
> IPC-D-275 and IPC-2221) based upon the maximum diameter of the plated hole
> instead of the drilled hole diameter?  Many suppliers drill the holes a
> little larger than the maximum diameter of the finished hole.  It seems
> like the pad size should be based upon the drilled hole since the annular
> ring is measured at the foil.  The fabrication allowances don't seem to be
> quite enough to accommodate this.  I'm sure this has been discussed
> before, I just need a refresher.
>
> Bill Dieffenbacher
> Lockheed Martin

##############################################################
TechNet Mail List provided as a free service by IPC using LISTSERV 1.8c
##############################################################
To subscribe/unsubscribe, send a message to [log in to unmask] with following text in
the body:
To subscribe:   SUBSCRIBE TECHNET <your full name>
To unsubscribe:   SIGNOFF TECHNET
##############################################################
Please visit IPC web site (http://www.ipc.org/html/forum.htm) for additional
information.
If you need assistance - contact Keach Sasamori at [log in to unmask] or
847-509-9700 ext.5315
##############################################################