View source for Master Lock No 1

= Master Lock No. 1 =

{{Lock model
| name = Master Lock No. 1
| Img = File:Mastercommercial.JPG
| Img_size = 150px
| maker = [[Master Lock]]
| lock_type = [[Padlock]], [[Cylinder]]
| lock_design = [[Pin-tumbler]]
| years_produced = 
| patent = 
| related = 
| spec_on       = true
| spec_comptype = [[Pin_tumbler |Pin-tumbler]]
| spec_comp     = 4

}}

The '''No. 1''' is a [[pin-tumbler]] [[padlock]] made by [[Master Lock]]. The No. 1 uses a laminated padlock body with an internal key-in-knob-style [[cylinder]]. The inner cylinder uses four pin stacks and does not use any [[security pin]]s.

The No. 1 is one of the most common low security padlocks used in the United States.

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== Principles of operation ==

The No. 1 cylinder is a [[pin-tumbler]] lock with four pin stacks and no [[security pin]]s. The cylinder typically uses the [[M1]] [[Key#Types_of_Keys|key profile]] but may use other profiles, as well. The standard No. 1 can be opened in both directions but the "commercial" series body restricts opening to clockwise rotation. The No. 1 is not a [[key retaining]] padlock.

== Disassembly instructions ==

The No. 1 cannot be disassembled non-destructively. To disassemble it the rivets that hold the laminated body together must be removed and each layer removed individually. The inner cylinder itself can be disassembled in the same manner as a traditional pin-tumbler lock:

{{Pin-tumbler standard disassembly}}

'''Notes'''
* The No. 1 cylinder requires a small diameter plug follower.
* The No. 1 plug is retained by a crimp, rather than a C-clip or [[cam]]. Above are the generic pin-tumbler disassembly instructions.

== Vulnerabilities ==

The No. 1 is vulnerable to a wide range of attacks. The reduced pin tumbler count and poor manufacturing tolerances makes it an easy lock to pick. It's commonly given to [[locksport]] beginners as a "confidence lock"; a lock that is easy to open and inspires you to continue picking. The No. 1 may be vulnerable to one or more of the following:

* [[Lockpicking]]
* [[Key bumping]]
* [[Impressioning]]
* [[Decoding]]
* [[Bypass]]
* [[Destructive entry]]

== Gallery ==

<div align="center"><gallery>
File:Master_Lock_commercial_no1_padlock.jpg
File:cutawaym1.JPG|A cutaway No. 1 padlock and cylinder.
File:Master Lock No. 1 insides.jpg|thumb|alt=Master Lock No. 1 insides|Master Lock No. 1 insides
File:Master Lock No. 1 Pins.jpg|thumb|alt=Master Lock No. 1 Pins|Master Lock No. 1 Pins
[[File:Master Lock No. 1 Actuator (1).jpg|thumb|alt=Master Lock No. 1 Actuator (1)|Master Lock No. 1 Actuator (1)]]
[[File:Master Lock No. 1 Actuator (2).jpg|thumb|alt=Master Lock No. 1 Actuator (2)|Master Lock No. 1 Actuator (2)]]
[[File:Master Lock No. 1 Actuator (3).jpg|thumb|alt=Master Lock No. 1 Actuator (3)|Master Lock No. 1 Actuator (3)]]
[[File:Master Lock No. 1 Actuator (4).jpg|thumb|alt=Master Lock No. 1 Actuator (4)|Master Lock No. 1 Actuator (4)]]
</gallery></div>

== See also ==

* [[Master Lock]]
* [[Padlock]]
* [[Pin-tumbler]]

[[Category:Lock models]]
[[Category:Master Lock]]
[[Category:Padlocks]]
[[Category:Pin-tumbler locks]]