Making A Key For A Junkunc Chain Lock
Posted: Tue Nov 10, 2015 9:38 pmA friend has a Junkunc chain lock, but no key. So took the time to make one. This is the lock.
Not exactly a large lock. But not the smallest Junkunc. Here it is with a United States quarter and a 1 Euro coin, so those on both sides of the pond have a size reference.
This lock looks similar to the 'wavy' key dual-sided wafer locks that have been around for quite a while. But this is not the same. First of all, there are no springs. The wafers are also a bit further apart. Unfortunately, don't know if this lock can be taken apart. (If you know, go ahead and post how it is done here, please).
These locks can not really be impressioned with an entire blank, since the key goes into a window inside the wafer. So you need to know what the key looks like if you can't get it apart. First step would be to pick the lock. (Not exactly rocket science picking these). Raimundo's Bogota set came out of my wallet, and a few seconds later, the lock was open.
Now that the plug is turned, the wafers are held in place, and will not move up or down. I tried to feel the heights with a pick and tried to file a key from the estimate of how the key would work, and guess what!?!? It failed.
Oh well, guess we got to do this the hard way. 
With the plug turned, even the correct key will not go into the lock. So took a small flat steel key and worked on one half of the key. Cut the key blank height down until it fits in one side of the keyway.
Now cut a bevel on the side where the center warding of the keyway is located, on the side of the key that faces away from the wafers you are trying to copy.
Now that you have the bevel cut, put the key into the lock at an angle so it fits over the warding, reaching in only as far as the first wafer so you know you have the height and angle of the bevel right.
Then turn it to be sure it can make the turn to fit flush in the keyway.
OK, that works. Now put the key full depth in the keyway. (Minds out of the gutter, guys).
Now if you turn the key, even though it looks like it goes all the way, it won't.
Why not? Because the wafers are held in place since the plug is turned a bit. NOW, you can impression one side of the lock. Ink the blade of the key, insert at an angle, turn it until it is stopped by the wafers, then jiggle it lightly. Pull it out and read the marks.
File where you see the marks.
Re-ink the blade.
Repeat until you don't get marks.
Again, this lock does not have springs. So hold the lock so the side you are trying to impression is facing up, turn the plug back to the locked position, insert the key, and tap the side of the lock a little to allow the wafers to drop against the key.
Apply turning pressure, and...
No, that was not my first attempt with the 'half key'. But that is the half key working.
Now, you do the same thing on the other side, right? Nope!
Copy the half key onto the correct half of the real blank.
Then use the half key facing the same direction as on the first side. Then it is a pattern for the mirror image.
Hurray!
Now you try it!
Gordon
Not exactly a large lock. But not the smallest Junkunc. Here it is with a United States quarter and a 1 Euro coin, so those on both sides of the pond have a size reference.
This lock looks similar to the 'wavy' key dual-sided wafer locks that have been around for quite a while. But this is not the same. First of all, there are no springs. The wafers are also a bit further apart. Unfortunately, don't know if this lock can be taken apart. (If you know, go ahead and post how it is done here, please).
These locks can not really be impressioned with an entire blank, since the key goes into a window inside the wafer. So you need to know what the key looks like if you can't get it apart. First step would be to pick the lock. (Not exactly rocket science picking these). Raimundo's Bogota set came out of my wallet, and a few seconds later, the lock was open.
Now that the plug is turned, the wafers are held in place, and will not move up or down. I tried to feel the heights with a pick and tried to file a key from the estimate of how the key would work, and guess what!?!? It failed.
Oh well, guess we got to do this the hard way. With the plug turned, even the correct key will not go into the lock. So took a small flat steel key and worked on one half of the key. Cut the key blank height down until it fits in one side of the keyway.
Now cut a bevel on the side where the center warding of the keyway is located, on the side of the key that faces away from the wafers you are trying to copy.
Now that you have the bevel cut, put the key into the lock at an angle so it fits over the warding, reaching in only as far as the first wafer so you know you have the height and angle of the bevel right.
Then turn it to be sure it can make the turn to fit flush in the keyway.
OK, that works. Now put the key full depth in the keyway. (Minds out of the gutter, guys).
Now if you turn the key, even though it looks like it goes all the way, it won't.
Why not? Because the wafers are held in place since the plug is turned a bit. NOW, you can impression one side of the lock. Ink the blade of the key, insert at an angle, turn it until it is stopped by the wafers, then jiggle it lightly. Pull it out and read the marks.
File where you see the marks.
Re-ink the blade.
Repeat until you don't get marks.
Again, this lock does not have springs. So hold the lock so the side you are trying to impression is facing up, turn the plug back to the locked position, insert the key, and tap the side of the lock a little to allow the wafers to drop against the key.
Apply turning pressure, and...
No, that was not my first attempt with the 'half key'. But that is the half key working.
Now, you do the same thing on the other side, right? Nope!
Copy the half key onto the correct half of the real blank.
Then use the half key facing the same direction as on the first side. Then it is a pattern for the mirror image.
Hurray!
Now you try it!
Gordon
