Manipulation techniques for opening
these manipulation resistant doors



These round doors use a unique combination lock design that makes standard manipulation techniques impossible. Very different from other locks, where the contact point is found by rotating the dial with a side to side motion, here the contact point is found with a down to up motion of the dial.

A special precision tool comprised of a magnetic base with a dial indicator - capable of measuring thousands of an inch - is needed in order to accomplish a successful manipulation.


The dialing is done in the standard  4L-3R-2L-1R fashion, except when in the final turning to the right, you must stop at 0, push down (hence the name) and continue turning right until the three bolts are fully retracted into the door.


  • There is only one contact point.
  • The contact point can only be felt when the dial is being gently and slowly raised after being pushed in.
  • It is precisely at this point where measurements are taken with the dial indicator.


The drive cam is shaped like a pyramid cone structure, decreasing in diameter towards the apex and increasing in diameter towards the base.

  • The dial can only be pushed in when set at 0.
  • The dial is under constant upward pressure by the dial spring. 
  • The fence in under constant side pressure against the wheels by the fence spring.
  • At the fully raised position of the dial, the drive cam acts a wedge and keeps the fence from contacting the wheels.
  • At the fully lowered position of the dial, the drive cam is dislodged and the fence is able to contact the wheels.


  • When contacting high areas in the wheels, the fence will move farther from wheel center.
  • This will cause the fence to contact the drive cam at a lower point (higher diameter, towards the base) in the pyramid cone structure.
  • This will result in the dial being positioned at a higher distance (farther from door face) when the contact reading is taken.


  • When contacting low areas in the wheels, the fence will move closer to wheel center.
  • This will cause the fence to contact the drive cam at a higher point (smaller diameter, towards the apex) in the pyramid shaped cone structure.
  • This will result in the dial being positioned at a lower distance (closer to door face) when the contact reading is taken.


Being mounted in the floor, these safe doors are usually dirty and even greasy, specially at fast food restaurants.

  • Remove dial and secure in a safe place.
  • Take out the four screws that secure the dial ring handle assembly to the door, sometimes these can be hard to remove, be prepared to use Liquid Wrench.
  • Remove dirt from door, making sure it does not come near or fall into the spindle area. Use a little brush as a broom and a little piece of paper as a dustpan. Use of a small vacuum cleaner is optimum.
  • Use compressed air around door face, specially around the spindle hole area, flush clearance between spindle plunger and door body with WD-40.
  • Wipe clean door face with a rag or paper towel.


The dial indicator and magnetic base are precision tools intended for machine shop use. They are available from different sources, in various brands and specifications.

  • Range 0 to 1 inch
  • Tolerance 0.0010 inch


Proper installation of the magnetic base and dial indicator takes time, you have to be patient and experiment with several configurations until you find one that works best.

  • The magnetic base is designed in such way as to permit unlimited mounting configurations.
  • Down and up travel of the dial must always be               parallel to the door face, imagine a flying saucer going down and up, there can be no tilting whatsoever.
  • The down and up travel of the dial indicator plunger must be perpendicular to the door face.
  • Make sure the complete down and up travel of the dial is measured by the indicator.
  • The tip of the dial indicator plunger must always contact and rest at the exact center of the dial hub.


The magnetic base and dial indicator must be calibrated to an initial reference setting. This is done so that you may return to the setting to verify and readjust (if needed) in case any parts are moved accidentally during the manipulation.

  • Turn dial four turns left to 0.
  • Move dial down and up, feel contact point.
  • Adjust indicator plunger height in such a way that the needle is approximately at twelve o  clock when feeling the contact point.
  • This adjustment is tricky, take your time, do not rush it, the entire manipulation process depends on this.
  • Once the base has been set and the indicator calibrated, this adjustment cannot be disturbed.


This is probably the most important and difficult part of all. The spring tension of the dial must be completely balanced out - zero buoyancy - in order to feel the contact point.

  • The dial only pushes in when set at 0.
  • Place index finder and thumb of left hand at approximately 90 and 60 on the dial.
  • Place index finger and thumb of right hand at approximately 10 and 40 on the dial.
  • Push the dial down completely and then, easing on the tension, gently go up to feel the contact point, repeat this as necessary until you are sure of the contact.
  • Use two hands to move the dial down and up, moving both hands exactly at the same time.
  • Do this while observing the needle on the dial.


Manipulation of these doors is challenging, you have to be able to see the numbers and dial them with the tip of the dial indicator plunger riding on the dial at all times. 

  • Create a new dialing index out of a piece of paper.
  • Dial the numbers upside down.


It is strongly recommended that before starting the actual manipulation, you practice by moving the dial down and up when feeling the grip of the contact point. Observe how much the dial travels when doing this. The newer the safe, the stronger the grip, the older the safe, the weaker the grip. In older safe doors, because of excessive wear, an audio amplifier might prove beneficial.


Compared to standard manipulation, indications from the dial indicator are huge, you wont believe how big they are until you see them, the numbers will jump right at you!

Because of the high precision of the dial indicator and the slippery grip of the contact point, readings can be unstable. Do not be concerned too much with small fluctuations - plus or minus 5 numbers - when taking contact readings. Gates usually indicate with an abrupt 15 number change.

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