Major Changes in Postal Mailbox Lock Regulations

New lock and construction standards go into effect October 2006.

By the time this article is published, the first major changes to mailbox regulations in more than 30 years will have taken effect. The essence of the new regulations basically comes down to new multi-unit mailbox units with new lock and construction standards. These changes become mandatory for new...

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New Lock

  • Modified Double D cutout
  • Will fit into the new and old styles
  • Tapered 12 degree cylinder collar
  • USPS-L-1172C on the face of the cylinder
  • Now able to handle up to a 3/16-inch thick cam
  • The C9100 will come without a cam
  • Cams are stainless steel
  • Comes with three keys
  • Two new keyways, 1,000 changes each
  • D4300 & D4301, Ilco # 1646 & 1646R
  • Spring clip
  • Drain holes on bottom of cylinder
  • Codes will not be released
  • D4300 codes 1000-1999 and 3000-3999, D4301 codes 2000-2999 and 4000-4999
  • Dust/rain shield required

Locks and key blanks are available through your local supplier. Original keys as stated above are D4300 and the reverse D4301. Ilco's numbers are 1646 and the reverse, 1646R. Costs on the original blanks are in the range of 94 cents each and the costs on the Ilco blanks are in the range of 42 cents each. The locks, without cams, cost approximately $6.89 each.

The new locks, which are superior in construction and security, have one visible flaw. If the intent is for locksmiths to use these new locks in place of the old ones, then why not sell multiple cams or cam packages that will allow us to install the new locks in place of the old mailbox locks currently in use? The USPS seems to have only thought this part through by making the locks work in old units without giving us the tools to actually do it. I'm sure some wise manufacturer will come up with a cam package to fulfill the expected need. At the time of this writing, CompX is working on this very project.

These regulations come after one of the greatest multiple housing construction periods in our history. With the much greater security offered by these new regulations, it is unfortunate that they were not adopted 30 years ago or even 10 years ago. Hopefully, we will see a gradual reduction in thefts from mailboxes.

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