the cam is put into the correct place for the fence to fall into it.
“Reversing the direction breaks the cycle, releasing that first wheel while it’s in the right place, and allowing the next wheel to be moved until its notch lines up with the first. This is how using the correct combination lines up the wheels so that their notches are in a row. Then the fence can fall into them and no longer stops the nose engaging with the gate, and the safe can be opened. That’s how the combination works.”
“And if one doesn’t have the combination?” he asked.
I smiled. “That’s where the skill comes in. A good safecracker can turn the dial and feel the slightest differences in resistance depending on where the fence is in relation to the wheel gates. If one gate is in the correct position, there is a different feel than if none of them are. Turning the dial to the left and right lets us feel the contact points of the nose on either side of the cam gate.”
“And what does that tell you?” he asked.
“Due to the manufacturing inconsistencies, the wheels are not precisely the same size. The fence, therefore, will rest on the biggest wheel. If one finds the gate on the biggest wheel, the fence will drop ever so slightly to rest on the next biggest wheel. This means the nose will also drop lower into the drive cam and will hit the contact points on either side differently. By trying a succession of numbers on the dial, one can work out the first number.”
He appeared to be following me, which was a point in his favor. It was a lot of information to drop on someone all at once.
“How is that done?” he asked.
“Many people create a graph of the contact points, which will show a noticeable dip when the gate of the biggest wheel is beneath the fence. In my case, I make notations of the relevant numbers as I come to them. Uncle Mick does it all mentally.”
“Does he? An impressive skill.”
I met his gaze. “Are you sure you wouldn’t rather have him do this?”
He didn’t answer my question. “What’s the next step in the process?”
“Once you have the first number, you can begin to work out the others. What I refer to as the ‘first’ number is not necessarily the first number in the combination, mind you. Just whichever corresponds to the largest wheel.”
“Which you cannot know from outside the safe.”
“Correct.”
“What then?”
“Once you’ve found one number, you can use that number and then work with it to follow a similar pattern. A good safecracker can detect those minuscule changes in the distance between contact points and use them to narrow down the combination.”
I realized I had been warming to my lesson and was leaning forward. He, in turn, was watching me intently, giving me his undivided attention.
“And that’s it in a nutshell,” I said, sitting back. “I’ve simplified things, of course, and there are variations by safe, but those are the basics.”
He nodded. “Thank you. That was quite clear and concise. I’m glad we decided to enlist skilled professionals for the task.”
I didn’t know why I felt oddly satisfied by this small show of approval. He was just the sort of person I didn’t want approval from. After all, he represented a great many of the things I hated: the haughtiness of wealth and privilege, the unmerciful arm of the law. Then again, perhaps it was just that fact that made me glad he realized my talent. I knew he looked down on people like me, but now he was aware how much skill was required to do what we did.
I picked up my teacup and took a sip of the now-cold liquid. At least it was still very sweet.
“Shall I order a fresh pot?” he asked. The politeness caught me off guard, but I supposed he was feeling generous now that I had spilled my secrets. “Or would you, perhaps, prefer something a bit stronger?”
“No. Thank you,” I said. “In fact, I suppose I’d better be getting home, if it’s all the same to you.” Nacy would be wondering where I was.
“Certainly,” he said, rising. “Shall I have my driver take you home?”
I shook my head as I finished setting my hat atop it. “It’s not far. Besides,” I said, drawing the veil down over my face. “It’s better to take precautions, isn’t it?”
He didn’t answer, but picked up my coat and helped me