Key machine adjustment. Too deep or too shallow?

[Raccoon]

I don't have time at time of posting to read all the replies, but here is my input.

I'd prefer leaning on the too-deep end of tolerence, eg +0.005. Here's why.

When you have a key that is cut too shallow, when it enters the lock, it is forcing the bottom pins too high and causes them to scrape the shell wall with no give (the key is solid).

But if you have a key that is cut too deep, when it enters the lock, the bottom pins sit ever-so-slightly too low, and the top pins have enough taper to jump out of the plug when turned. There is no scraping, because the top pins naturally rest on the plug surface with light springy force. The lock is happy.

[Raccoon]

Mind you. In case there's any confusion; Bottom pins only have slightly tapered edges, to compensate for the round surface of the plug. The tapers on bottom pins DO NOT assist with imperfect keys, the taper only exists to prevent the corners from scraping against the shell wall (again, due to the curved surface of the plug).

Tapers in top pins exist to help them escape the chamber when there is natural wear in the key. They can do this with as much as 0.0015 to 0.0030 wear, sometimes more. So being +.0005 too deep is Just Fine.