Painless shimming of an American cylinder

[Chucklz]

Shimming American padlock cylinders can be a real pain. The serrated pins and the occasional serrated mushroom top pin can really do a number on your shim. Well, I am not a locksmith, so my stock of well shimstock is rather precious to me. Here's how I get these beasties to play nice.

Insert cylinder upside down in a vice, close gently. Face the back of the lock so it is easiest for you to manipulate the shim. Insert shim up until you hit the last pin. Now for the good stuff. Using a bit of stiff wire, or a needle in a handle, push the last pin up (down actually) past the shear line, to about what a 0 cut would be. Now, gently and slowly let the pin rise, while gently feeding in the shim. With a serration, you can feel the shim move in a bit, but no further. Keep pressure on the pin, pull the shim out a tad and try again. Spools get "trapped" by the shim, so they are easy to recognize.

The overall trick is keeping the pins under control. Always keep a bit of downward force on the stack you are working with. You can easily tell serrations and spools, and thus can save your shims.

[Darek84CJ]

American cylinders have very tight tolerences. I have had best luck shimming Americans with .05mm shim stock.

Americans are tricky with the millions of serrations they have, but like Chucklz said, if you feel it getting caught, slowly back the shim out a little, let the pin fall down a very minimal amount, and try again. Eventually, you will hit the shear line instead of a serration.

[Luke]

Ive found that shims are a great way to open locks if you need to, and either cant pick it, or are lazy. I kinda share the same views with the local locky. Just for beginners just remember, like pushing on the shim and if you're using a keyblank WIGGLE. WIGGLE = useful! I have no problem acquiring shim stock, it is just that i use it sooo very rarely that i still have a LAB pack of twenty from last year that a locky brought for me. Another great thing u can do if frontal shimming! I can't be bothered explaining but im sure someone else would elaborate!

[Darek84CJ]

"Frontal shimming"??
What would be the purpose of any lock then, if you could just shim it from the front?
No lock I own, and I own many, can be shimmed from the front, there is always a lip covering the shear line.

[Luke]

Get a dremel and remove the lip! Then shim, the lock still works with the key after wards!

[Darek84CJ]

But then that removes the "high security" aspect of the high security lock. I don't see the point, when you can just do it from the back
Please elaborate...

[Chucklz]

You could use this technique if you were unable to access the back of the lock, and if drilling would be a poor option.

[Luke]

Exactly! for example drilling lock with hardened inserts and the such. Frontal shimming is great for that!

[raimundo]

shims that are not curved are easily found in the parking lot of best buy or any large store that uses little white or black rectangular plastic capsules stuck on the packaging. ( the shoplifting tag ) there is a suitable shim in each of these capsules, and I have found two shims in one of them. About locks that shim from the front, Many years ago, a small cylinder was made for aluminium frame glass commercial doors, it was calle a peanut cylinder by Jack llewyelln of cerny's locksmith in sanfrancisco. These 1960s era cylinders could be shimmed from the front. Of course if a thief wanted to get in, a brick through the glass was faster. Whenever working with cheap knockoff locks made in some country that hasn't discovered electricity, just check the cylinder to see if there is a lip. Then pick it, just as fast as shimming on this cheap stuff.