Rises on keys

[LockManipulator]

Ok so I should know this by now but I have no idea. Why do some keys have rises on each side of where the pins sit? It just makes it not as smooth to use the key! You can see where it goes up and then down on the key; why can't it just go up or down to the next depth?

[rai]

most keys are like that, the tiny peaks are an artifact of the shape of the cutting wheel on the key cutting machine. They also confuse and baffle anyone who is not familiar with locks and who will tend the think of those things as absolutly necessary.
they also can make it hard to remove the key in any position except top dead center.
if you see a key without them, its probably made by impressioning

when the bottom pins are pressed to the cylinder wall the key cannot be removed because the pin cannot move down into the key and cannot move up into the cylinder wall. keys made without this that might have a downward slant, could be pulled right out of the lock while the cylinder is in an unlocked position.

you may occasionally see a plug turned in a lock that seems to indicate picking, but before concluding the lock was picked, you should examine any copies of keys to see if these little tips are cut off

key machines are calibrated for the depth of the cut but changing to a different angle of cutting wheel, can mean that the width of the cutter can impinge on these tips as it makes the pin set bottom wider,
a copy of a copy of a copy, (third generation copy) can have them totally eliminated. The angle of the cutting wheel can be different on different machines, so this is always possible.

[LockManipulator]

Thanks that cleared it up! I don't think i'm ever going to make a key with them though haha They annoy me so much! I have this pet peeve against keys that don't smoothly operate

[Farmerfreak]

You can see where it goes up and then down on the key; why can't it just go up or down to the next depth?

It can go straight to the next depth, no reason for it not to with the notable exception of a key that goes from shallow to deep cuts only.

Automotive keys for the last decade have all been cut from one cut to the next without those peaks in between. Unless someone cuts a new key with the peaks in between..

[Medecopen]

I was wondering the same thing I used to think the high spots pushed the pins up lol..
I have a key I made without the highs I actually grinded them off with a dremel because it got stuck in my lock, I didn't want to try and file nice slopes and take take a chance of filing any deeper... Now it works very smooth almost to smooth almost like there's no pins in there... And once I did notice the plug turned half way and thought wtf I don't remember picking it... Maybe that's what happend in my case... I'd like to get better at filing keys and prefer them to have ridges for a natural feel and also for security... If there's a chance to leave a plug turned that's easy pickings (pun intended) for a burgular...

[Neilau]

As Rai said, they stop the key from being withdrawn unless it is TDC.

Famerfreak's mention of car keys reminded me of car door locks on cars from the 60s. GM and Fords.

Often (very often) people would remove the key without returning it to TDC. Effectively, the cylinder was turned in the lock and thus could be opened with a small coin or similar.

[ckc123]

As Rai said, they stop the key from being withdrawn unless it is TDC.
.

and on some lock types you need to rotate the keys greater then 180 degrees to open the lock.. if the key can be pulled out when not at TDC then if it's rotated without the key, then all the top pins will get pushed into the bottom of the keyway and jam the lock up..

They are there for a reason, and should be kept for "normal" use.

They also help keep the pins moving more freely (more travel).. if you only push them up to the needed depth, then it sets a wear pattern which will tend more to jam in those extended positions

[GWiens2001]

They also help when the key and pins are worn. Pulling out slightly will raise the pins a little more, allowing the key to work when there is heavy wear.

Gordon

[GringoLocksmith]

In my locksmithing school, the teacher said the rises were to prevent the cuts from being exposed to unnecessary wear. I think rai's explanation is better, though.

[magician59]

In my locksmithing school, the teacher said the rises were to prevent the cuts from being exposed to unnecessary wear. I think rai's explanation is better, though.

Both are actually quite right. The geometry of the cuts is specifically designed by each manufacturer to accomedate the design of the pins' shape and size. The seat (actually called ROOT) of the cut should be flat and parallel to the bottom edge of the key blank. Its width will vary to allow for the contact (champhered) end of the pin. (eg. Observe the differences in the cuts and corresponding pins in a Kwikset cylinder, as compared to those in a Schlage cylinder.)

The ramps between cuts, although they DO intrigue and confuse the uninitiated, are designed for ease of insertion and withdrawal of the key.

Several things may affect this ease of insertion/withdrawal:
Dirt or debris in the cylinder
Lack of proper maintenance (lubrication)
Improperly cut keys (The angle may be too steep; or there may be "hooks" caused by a flat side of a cutter, on a deep
cut)
Over-stacking the pin chambers (using too many pins, or pins that are too long for the spring(s) to properly compress)
Worn key way (or inexact key blanks), causing the users to wiggle the keys to get them in and out
Worn pin chambers--pin chambers that have become out-of-round, commonly caused by users, pulling the door open
with a turned key

The list isn't exhaustive; but I think you can see that "Why don' my keys work?" can have a complex answer.