Replace a broken doublecylinder deadbolt lock with a new one. Use smartkey technology to match the lock to your existing housekey.

Double deadbolts have a keyhole on both sides and are intended for use in doors with a glass window, so that a burglar cannot break the window, reach in, and unlock the deadbolt on the inside. But I put them in all my exterior doors with the thought that a burglar may come in through a broken window, but he is going to have to go back out that window, too, because he can't get any of the doors open.

I installed the original deadbolt in this video 14 years ago. According to Kwikset's webpage, their products have a lifetime warranty. I'm pursuing that and will see how far I get in obtaining a replacement or refund. The result will be reported here.

http://www.kwikset.com/customersuppo...

UPDATE: I spoke with customer support at Kwikset (1800327LOCK (5625) ). I wish I remembered the name of the representative I spoke with; he was both pleasant and professional. I described the situation. He said he would need a picture of the old deadbolt, the new one, and the bottom of the box. I showed him this video and asked if it would do, and he said of course. So a replacement lock is on its way to me. They don't do refunds, but I can take it to Home Depot and see if they will.

To purchase a Kwikset: http://amzn.to/2aR1lWx

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