Important Information About Jimmy Proof & Rim Cylinder Locks

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We want to clarify a common misconception regarding jimmy proof lock failures.

The real issue

The problem does NOT come from the rim cylinder key section itself.

We’ve seen frequent failures with jimmy proof locks from brands such as HALCO and ILCO, where the locks break internally. The failure point is the internal mechanism inside the lock body on the inside of the door, not the rim cylinder.

Disclaimer
Serrurier Shay is not affiliated with, endorsed by, or associated with HALCO, ILCO, Yale, Mul-T-Lock, Medeco, ASSA ABLOY Group, Kenaurd, Canstar, USstar, Maxtech, or Northstar. All brand names are mentioned for identification and comparison purposes only, based on field experience and service history.

Many jimmy proof locks manufactured since the 2000s use brass internal components, which tend to wear and break over time—especially when the door is not perfectly aligned and the lock is forced.

Brand quality comparison

  • HALCO & ILCO: internal mechanisms tend to break often

  • Yale: produces higher-quality jimmy proof locks, but they are significantly more expensive

Door alignment matters

If the door requires pulling or pushing for the pin to drop into the striker, the lock will bind. When users force the lock, internal parts eventually fail, causing:

  • Free-spinning outside cylinders

  • Complete lock failure

  • Customer lockouts

Best long-term solution

The best solution is to convert a jimmy proof lock to a single deadbolt lock.

⚠️ Important note for thick doors (2¼”–3”)
Many double deadbolt locks use a two-finger tailpiece design. If the lock is forced:

  • One finger can break

  • The lock may still turn

  • The door remains locked → total lockout

Recommended high-security option

A Medeco deadbolt is the best solution:

  • Uses a flat tailpiece

  • No finger-style tailpiece to snap

  • Much stronger and more reliable under stress

All opinions are based on field experience and repairs.

Serrurier Shay – Locksmith
📞 514-836-9097
📧 info@serruriermontreal.com