Schlage Consumer Lock Tolerances

[misterj]

Out of boredom today, I was playing around with a typical ~$20 Schlage consumer grade entry lock. I duped the key and got one three generations down that still worked flawlessly. Started to wonder how flawed the key could be and still work.

Well, I got out a dremel and started filing down this 3rd gen key. I was pretty shocked with how far I whittled it down with it still working. I rounded out the spikes in the key and knocked every cut down by around a half a depth, then knocked the cut closest to the bow to what is approximately a #7 cut. The original bitting was 44646 and I have one that's effectively 74646 with the 4646 cuts being a little deeper than they should be (measured with a Schlage metal gauge). The key works absolutely flawlessly. It's a little alarming that one cut could be three levels deeper than it should be and the key works flawlessly.

Here's the key in that state next to the original:



Makes me wonder if Schlage's consumer quality really is much better than Kwikset. I'll have to try this with a Kwikset some day and see what the results are there.

Eventually I filed it down to a 75757 (after I took the picture) and it will still work, but it requires a little bit of determination (no, not treating it like a bump key, but it's not going to turn first try by any means). Just very interesting

[bobhdus]

You should disassemble it and inspect the pins. I have a code machine that I cut Schlage keys with when I do a rekey and duplicate the extras keys on a duplicator. My duplicator is fairly accurate but every now and then I have to make adjustments because the copy keys might not work as smooth as the Code cut keys. My Code machine is a Framon 2 and cuts to .0005" and I "touch off" on my duplicator every time I use it. If this lock had been apart before it's possible someone did not put all the top pins back into it. Usually Schlage has some factory spool/ security pins in their locks as well.

[Evan]

@misterj:

Gut the lock, it sounds as if you have a very worn/grooved plug in play, chamfered pin chamber holes or a rounded bottom pin incorrectly installed as a top pin to have that much "tolerance" in your lock...

~~ Evan

[gibson]

you indicated that it is a $20 entry set, which is most likely a Schlage 'F' series, that has a compressible 'bible'. These locks don't seem to have as tight a tolerance as their higher priced models, or even their standard deadbolts. but a difference in three pin sizes (for Schlage, .045in.) is kind of high. try taking an impression of the key you made, and see if the pin is resting on the slope of the cut. also, did you have to wiggle the key at all in order for it to turn, or was it the normal pressure that you would ordinarilly use to turn it?

[misterj]

The lock is a brand new one. I pulled the cylinder and all pins and springs are there. I can't get away with any more filing, but that's still a dramatic difference from the original. I could dupe generations upon generations of keys and they still work. I don't know exactly how far I could get away with because I got sick of cutting them and burning through blanks. The machine isn't calibrated perfectly either (project for another day), I can forget about more than one generation on a Best key.

The tolerances definitely aren't as tight as the commercial stuff. I have Everest C145 on the house and I can't even change one cut one depth on those locks.

It works just like a normal key. I can't just put any random key into the cylinder, but it seems like as long as the basic pattern is there and it's sort of close it will work.

I've run into this before--I used to have a lock like this on my front door and one of my old work keys had a similar bitting (I think the house was something like 37643 and the other key was 38743) and I accidentally used it with it working perfectly. I couldn't do it consistently at all, though...that may have been a case where the deeper cuts and the specific force I used were basically allowing me to bump the lock open. That was one of the reasons I went to the Everest stuff...plus nothing was keyed alike and I had never seen an Everest before so it was an excuse to buy a bunch of locks and key everything alike.