Modern handcuff failure points

Joined: September 23rd, 2016, 2:33 pm

July 29th, 2018, 4:34 pm #1

I have been watching a video from a US law enforcement officer talking on a live stream. He got a question about the life, usage and replacement of handcuffs.

The officer said typically they use handcuffs until they break and don't replace them before that. He said usually they break while on the person and they can't get them off, so it's not too much of a risk for the officer as far as securing people. They take them back to the station and cut them off. But he said they usually fail on the person and they cannot undo them. So this got me to thinking. I am not an expert but I have seen handcuff cut-throughs and have had (and still have some) many handcuffs over the years in my collection. So what exactly are the things that could be going wrong with the handcuffs that would get them stuck on the person to where the key does not work?

This is the example that he has:


I am torn between thinking it's a problem with the key or the cuff. Since the key gets stuck, at least in THIS particular instance, I personally believe the problem is with a worn key that the bit on the end is either no longer sticking out long enough or has become rounded so that it catches on the ledge of the pawl to raise it but too much force during the keyturn and it scoots off the ledge and the pawl snaps shut behind it. That is my only theory at this point.

If anyone with more experience has any points to add to this on how modern handcuffs fail during use and why it happens? I would be very interested and I think it could be helpful for people in occupations where handcuffs are used, so that perhaps people can make better decisions on maintenance and replacement.
Quote
Like
Share

Joined: May 29th, 2018, 5:08 pm

July 29th, 2018, 8:21 pm #2

On Handcuff day in my police academy, one of my fellow cadets got his brand new Peerless cuff stuck on one of his wrists.  Since it was not double locked, I was able to shim it open.  The also brand new key got trapped inside the lock.  I told him to return the cuff for another so I never had the opportunity to take the cuff apart to see what exactly had failed.  I wanted to get some catsup from the cafeteria and smear it on his arm when walking back to class but he was not as warped as I was. Would have been a memorable time for the class when they thought I butchered his arm all up. 

Close to me, there is a training facility that trains snipers and such to fight in Afghanistan.  Twice they brought over an unfortunate trainee to have me cut the cuffs off.  They had the exact same problem that I had in the academy.
The best way to cut off a cuff is; get a bucket of water, a rag and a Dremel.  Stick the rag under the cuff and dunk the arm in the bucket of water. Cut the bow as close to the lock as possible.  Every 3 or 4 minutes, dunk the arm in the water.  It takes about 10 minutes to do it as it is best to go very slow.
  
Quote
Like
Share

Joined: September 23rd, 2016, 2:33 pm

July 29th, 2018, 8:37 pm #3

So perhaps this is related to my theory, but in this case maybe a defect from day 1 where the ramp that comes into contact with the key flag was malformed or not long enough it's self, so the key was able to scoot off the end with enough force? If the key gets stuck farther into the cuff than normal with no way of seemingly getting the key out, it is the only thing that makes sense to me. Which would explain why it happened with brand new cuffs and why my theory would happen after worn keys are used.

If you see this again, try this theory. Shim the cuff open to free the person if you have shimming ability near by, then if the key is still stuck, turn the key as far in the same direction as normal to undo the single lock, then manually push up the pawl while you have the rotating arm not engaged and while the pawl is pushed up (simulating the normal key mechanics) see if you can crank the key backwards and free the key from the handcuffs. I believe that might work. Although if the issue happened with a brand new key and brand new cuffs, they should be returned. But if it's an old key that was the issue, a quick test with a new key with harder than usual force should determine if the cuffs themselves are defective. Hell, that may even be a good test for everyone with new cuffs, to try and "open" them somewhat (but not insanely) forcefully, in an attempt to expose a defect before the cuff gets on someone's arm?
Quote
Like
Share

Joined: January 17th, 2016, 10:08 pm

July 30th, 2018, 4:16 am #4

The theory of the key's flag being to short has come into play in the past. Most notably, it happens when one tries to use a modern, standard key in a WWII era Harvard Lock Co. Cuff or leg iron. Once the standard key is inserted and twisted in the unlock direction, the flag tends to skip past the lever that moves the pawl and become trapped. You cant turn the key back to release it. Ron Spitz showed me, if you manually push and hold the pawl down, you can wiggle the key back and forth and get the flag to pass the lever and release the key. I had tried it for quite a while, not pressing down the pawl. It was a no-go until the pawl was held down. It allowed the flag to slip past the pawl lever, with a little bit of coaxing. I did have a set of Hiatt UL-1 cuffs fail after some use. The key, just wouldnt turn in the lock at all. Something was holding the pawl in place? I never figured it out. But, Hiatt sent a new pair as a replacement.
-Richard Knip-
Quote
Like
Share

Rasberius
Rasberius

July 30th, 2018, 6:35 pm #5

In Russian handcuffs-related group there is an explanation of Peerless handcuffs flaw. You can use Google Translate to read the explanation
https://vk.com/photo-5531056_148372191
Quote
Share

Joined: September 17th, 2015, 3:43 am

August 2nd, 2018, 3:44 pm #6

I just posted about a new set doing the same thing. New s&w model 1 handcuffs and new keys. Even tried other known good keys. Key ended up getting stuck and wouldnt undo the double lock. Had to cut them.off and sent back to where i bought them. Sure hope its not gonna turn into a issue. Its clearly a manufacturer defect on those. Also hoping the quality of new cuffs has not gone down.
Quote
Like
Share

Joined: May 2nd, 2018, 7:05 pm

August 9th, 2018, 9:43 pm #7

IMHO the biggest failure of handcuffs used in North America is hands down the pathetic security offered by the "Universal Key." Steve Santini
Quote
Like
Share

Confirmation of reply: