I recently got one of those little Champion 6 lever locks on Ebay for $6.95 with no key. I've noticed a lot of these locks seem to be without a key. Some of them go for a pretty high price too. I searched for some information on picking them and didn't really find anything. There was a post on another site from someone that tried to make a small set of calipers from thin wire, but there was no indication of what the results were.
There is no way I could find to tension the lock. You can push in on one lever at a time with a piece of wire, but there is no feel when the gate slides by the locking arm. There is very little tension on the lock to begin with, and it only increases slightly when you move a specific one of the six levers. If you could somehow detect the gates, you would need a way to hold each lever while you moved the others. The locking arm can't move into the lever to hold against the spring, so as soon as you let go of it the lever returns to it's resting position.
Pulling out on the shackle seems to bind against the locking arm. If you take out the lever pack and just leave the locking arm and shackle in place, pulling on the shackle does not provide any movement or force on the locking arm. Pressing in on the shackle actually removes tension because the shoulder part of the shackle presses against the other side of the locking arm.
There is also only about .010 or so gap between the body of the lock and the shackle. So there is really no good way to slide something down deep enough to provide tension. Maybe some locks would be a bit looser .
Some dimensions. In inches.
Levers are .050 thick.
Keyslot is .060 x .330
Wire I used is .039
I sanded a brass safe deposit blank so it fit the keyslot. It ended up .325 x .052 Here is how the levers and gates look inside the lock.
I marked the wire tool with nail polish to indicate the direction of the bend. You can carefully insert the tool and press in on lever two for example, then turn the tool 90 degrees to feel the gate in the adjacent levers. Once you hook the adjacent gate, measure accurately from the body of the lock to a specific spot on the tool. I used the little cap that tightens the grip of the tool. So long as it's accurate and the same place each time. Make a list of each gate like below.
Lever <> measurement
1 <> .550
2 <> .462
3 <> .595
4 <> .620
5 <> .570
6 <> .627
Now take the longest measurement in my case lever 6 it is .627 and find the difference for each lever.
1 (.627-.550) = .077
2 (.627-.462) = .165
3 (.627-.595) = .032
4 (.627-.620) = .007
5 (.627-.570) = .057
6 Longest .627
The longest measurement ends up being the uncut place or the full length of the key and each other measurement is the depth of cut needed for that lever. So that pin 4 for example is a depth of cut of only .007 and pin 2 is the deepest cut in our key of .165
Now grab a dremel and make the key. Cut carefully. If you cut too much just shorten the longest one, (pin 6 for me ) and start again.
The gates are fairly wide in my lock. Also you can move the key a bit left and right, up and down when you try it in the lock. Once you get the lock to open, there seems to be some bounce in each lever due to the extra width of the gates. At this point you know the locking arm is in the gate, so you could use a wire against the levers where the key would contact, rather than trying to feel for the gates. This should let you be more precise in your measurements and perhaps touch up your key or make a more accurate one.
Sometimes the wire tool will get stuck in the lock. Just try to be gentle and don't pull too hard. Pushing the tool in deeper and slowly twisting to locate the bend and line it up so the tool can be removed seems to work. Make sure the tool stays straight with the body of the lock. Also sometimes the levers will move apart a bit and allow the tool to get between them. This can be useful when you try to measure some of the deeper (deeper into the body of the lock from the keyslot) gates. When you measure the deepest gates the lever you are moving to put your tool in place can sometimes reach full travel before you get the tip of your tool in the gate you want to measure. If this happens, you can try to slip the tool between the levers intentionally, or you can just mark down the measurement as unknown. When you are making your key leave this lever till last and take a few thou and try the key. Repeat this procedure until the key works.