Has this been modified?

[Mrfoto]

I’ve never seen a drive cam this beat up before. Just wondering how it got that way.

I guess I should add it is a Sergeant Greenleaf 6725 from about 1969

[Mrfoto]

It looks like someone hit it with a hammer right on each contact point. Could this be some oldskool locksmith mod that causes issues with manipulation? This lock didn’t plot the same way twice nor showed ANY gates thru the procedure. None!!!! The stem was one full turn loose and the whole lock performed like it was lubricated with molasses. There were no stuck flys and the molasses feel turned out to be in the dial ring bushing mostly. Now that it’s cleaned and reinstalled it still doesn’t plot like any other lock I have worked on.

Makes me want to hammer on another cam and see if makes it more manipulation proof.

[MartinHewitt]

There can be other issues or peculiarities, that can lead to such behavior. It looks like the spindle is a bit short. Short spindles make it more likely that the drive cam is not sitting tight on the spindle. When the drive cam can shift it makes the manipulation a hell. It makes it also more likely that the spline key falls out and safe doesn't open anymore with normal dialing. Of course this can also happen with a spindle of proper length and a loose spline key. Invisible gates can also happen by accident if a certain combo is set and the gates are shadowed.

[Visitor]

It's not a locksmith trick it's just wear. Old locks used a few times a day for years and years get all manner of wear you wouldn't expect.

[mastersmith]

This wear would be consistent with years of bolt end pressure while locking up. The fence would be forced into the cam.