Everything I Know About Schlage Primus By: Supallama, MMDeveloper;
Last Updated: 2017/08/08

Prologue

This is to serve as an exhaustive wall of information with all I know about the Schlage primus, and learning how to pick them. I think primus locks are the intermediate level high-security locks and they aren't as difficult to pick as a lot of people think they are. There is a lot of misinformation, and partial information out there which can lead to frustration when learning how to pick them.

I've been picking Primus locks for some time and I've come across lots of information; some good, some bad. This will be a continually updated document for what I know to be factual and/or useful.

What Is A Primus

The Primus is a UL 437 rated pin-tumbler(P/T) made by schlage. It uses 6 P/T's and a sidebar that requires five finger pins to be lifted and rotated properly. The primus is functionally identical to the ASSA Twin Combi but does not include as many pick resistant features or key control.

Primus Picking Philosophy

The way a Primus lock works, is that in addition to the standard P/T keeping the plug from rotating, there's also a sidebar (literally a bar that runs along the side of the plug) that fits into a groove in the core wall. Lifting the pins to shear will take care of one shear line. Then it is down to lifting and rotating the finger pins to the correct positions for the sidebar to engage.

Trademark Security Mechanisms

Sidebar Finger Pins

The primary security feature of a Primus lock is that not only do you have to lift the pins vertically, you also have to lift and rotate the finger pins to the correct height and angle in the finger pin chamber. This will allow the sidebar to interact with the finger pin.

The finger pins have ears (Illustration ::0) to facilitate this lift / rotation from either a key or pick with a maximum turning radius of 60 degrees.

Illustration ::0
Sidebar Pin Finger
Illustration ::1
Finger Pin Sidebar Groove

Sidebar

To complement the finger pins that must not only be lifted to the correct height, but rotated as well, the sidebar is what interacts with these finger pins(Illustration ::1). The sidebar is a device that runs the length of the plug (Illustration ::6), and sits between the plug and the core wall. Through spring pressure, the sidebar wants to push against the core wall. The sidebar has little cut outs (Illustration ::1) that mate through the plug with the finger pins gates (Illustration ::2).

When the finger pins are not rotated properly (Illustration ::3), the gates are not facing the sidebar. This causes the sidebar to protrude outside of the plug and into the grove inside the core wall. When the finger pins are rotated properly (Illustration ::4), and all the gates are facing the sidebar, the sidebar (as a whole) will interact and engage the finger pins.

When the sidebar fully engages with all of the properly rotated and lifted finger pins, it will be given the ability to sink inside of the plug and out of the groove in the core wall (Illustration ::5). Provided all other mechanisms of the lock have been satisfied, the lock will open.

Illustration ::0
Sidebar
Illustration ::1
Sidebar with Finger Pin
Illustration ::2
Sidebar Channel (no pins)
Illustration ::3
Finger Pins Misaligned
Illustration ::4
Finger Pins Aligned
Illustration ::5
Sidebar Engaged
Illustration ::6
Sidebar Groove

Great Tolerances

The machining tolerances inside a Primus lock are very good. There is extremely little, to no, slop in a Primus lock and heavy tension is not required but recommended. This is not your $2 gas-station lock.

Identifying A Primus

Branding and Logos

If you have clear view of the face of the core, you can determine which style of Primus P/T lock you have.

Typically there are only 2 logos that signify a style of Primus lock and they are always placed just above or to the left of the keyway. There's the "PRIMUS" logo to indicate it is a Primus (Illustration ::1) and an Everest stamp to the left of the keyway as well as the "PRIMUS" logo above the keyway to indicate it is an Everest primus (Illustration ::0).

Illustration ::0
Schlage Everest Primus
Illustration ::1
Schlage Primus

Finger pin Movement

The Primus finger pins have a maximum rotation of 60 degrees.

Schlage Primus

Security Mechanisms

  • Tight Keyway
  • 0 Security driver pins
  • Key Pins lift to shear
  • Limited pin rotation/height for a sidebar
  • 0 false gates on all 5 finger pins

Tools Used

  • 0.030" TOK Prybar
  • Southord Deforest Diamond
  • Finger pin pick

Picking

These are probably the most fun version of Primus locks to pick, in my opinion. Their tight keyways offer some degree of difficulty and the satisfaction of defeating this locking system is equivalent to defeating an ASSA Twin 6000.

I found heavy tension works well on these locks, simply pick the top stack then move to the finger pins.

My picking technique as follows:

  1. Pick top stack. get slight core rotation signifying top stack picked (standard drivers so I would expect a false set feeling to be picked as opposed to spools)
  2. Crank down on tension (helps to find the binding finger pin)
  3. Slip the finger pin tool under each finger pin, as centered as possible tap each finger pin as to slightly lift them, if they don't bind nothing to worry about as the spring will push them back down
  4. Once the binder has been identified decide whether to push or pull the finger, I tend to push the finger by rotating my pick slightly CCW, hook on to the finger and pushing the pick in to the lock further. then slip the pick under the pin center lift slightly and then get back to the finger and hook the finger with the pick and pull towards you sweeping the pin from full left to full right. then repeat the process.
  5. At this point you will either set or over set the finger pin, you know it is set by either a sharp click or a small movement in the core or both, you may even feel it. If you have overset the finger pin release tension very slowly until you hear a small click, if you leave your finger pin pick in the lock you may feel the finger pin hitting the pick. then repeat step 4.

I have found after 2 or 3 pins are set a noticeable amount of rotation happens on the third or second set pin, just continue finding the binding finger and set them, I also do not force the finger pins back down I simply release tension to drop the finger pin, on some occasions the finger pin has dropped in to the correct height / rotation and set itself.

Schlage Everest Primus

Security Mechanisms

  • Tight Keyway
  • 0 Security driver pins
  • Key Pins lift to shear
  • Limited pin rotation/height for a sidebar
  • 0 false gates on all 5 finger pins

Tools Used

  • 0.050" TOK Prybar
  • Southord Deforest Diamond
  • Finger pin pick

Picking

The mechanism is the exact same as the Primus so picking is no different, The warding is somewhat less intrusive so it has less play in how much you can maneuver your picks in the keyway.

What I like to do is apply heavy tension to the lock. Using my Deforest Diamond, I search for the first binding pin.

Primus do not usually have a set binding order like back to front. The standard pin chambers will set to shear easily. Once the last pin is lifted to shear it's time to move to the finger pins. Following the tactics for this, discussed above, the lock opens.

Primus/Everest Primus Interchangeable Core

The Primus I.C. systems do not work like a BEST or Medeco I.C's where they use a control sleeve and multiple sheer lines within the stacks to engage a locking bar in to the lock body, instead the Schlage I.C. systems have a seventh half pin located at the very back of the lock. This half pin is under spring tension and acts like a standard pin stack that engages a control ring, this ring when rotated 20 degrees clockwise pulls back on a locking lug which then allows the I.C. to be removed or placed in to the lock body.

Security Mechanisms

  • Tight Keyway - Primus
  • Open keyway - Everest primus
  • 0 Security driver pins
  • Key Pins lift to shear
  • Limited pin rotation/height for a sidebar
  • 0 false gates on all 5 finger pins

Tools Used

  • 0.050" TOK Prybar - Everest primus
  • 0.030" TOK Prybar - Primus
  • Southord Deforest Diamond
  • Finger pin pick

Picking

The mechanism is the exact same as the standard Primus Mortise, rim, or key in knob (KIK) so picking is no different.

What I like to do is apply heavy tension to the lock. Using my Deforest Diamond, I search for the first binding pin.

Primus do not usually have a set binding order like back to front. The standard pin chambers will set to shear easily. Once the last pin is lifted to shear it's time to move to the finger pins. Following the tactics for this, discussed above, the lock opens.

There is no set tool for picking any Schlage I.C. in to control at this current time, some have used a tip from a control key and placed it where the control key would engage the seventh half pin, then pick the lock to control. Others have picked the lock then rotated the plug 180, using a hook the seventh pin upper half is depressed and the drivers pushed back up in to the bible and using a tension wrench rotating the plug to control.

Learning How To Pick A Primus

The Primus mortise cylinder is probably by far the most readily available Primus lock online for decent prices. My favorite place to find these is doing an Ebay search for "Schlage primus". Usually you can find them for roughly $25-$30 a piece without keys($40+ With keys). Read the descriptions and make sure they have pins in them and are not just "sub assembled".I also pay attention to the keyway it may be an Everest primus despite the ad stating "Primus".

Progressive Pinning

This is by far the most recommended method for learning to pick Primus locks. To get accustomed to moving a pick around a Primus, you'll want to empty all of the pin chambers. If your lock came with working keys, make sure to keep each chamber separate. If you mix the pins up, your key will not work again until the pins are back in the correct chambers, orientation, and order. If your lock did not come with keys, you can mix them up all you want.

Now, pick any finger pin and any spring. What we're going to do is put one of the finger pins back into chamber one, Flip the core upside down drop in the spring in to the smaller chamber closest to the front of the keyway and then drop the finger pin after it, there is a small hole in the top of the finger pin for the spring to rest in (With ear facing in to the keyway and the larger end touching the core wall) then re-assemble the sidebar and springs in to the plug (sidebar has no right way, Sidebar springs will be significantly smaller than the finger pin springs or top stack springs) then reassemble the rest of the lock, You've just pinned up your first practice Primus lock.

Use your tension tool to tension the lock, and use your pick to slide under the finger pin. Under moderate to heavy tension push or pull the finger pin away or towards you (to pull hook the finger pin ear with the finger pin pick) then position the pick as center to the finger pin as possible and lift the pin slightly, then do the opposite to the push / pull you did before to "sweep" the finger pin from full left to full right or vice / versa. Continue to do this motion until you get an open. If you feel you have over lifted the finger pin slowly release tension until you hear a click of the finger pin dropping and start over until open.

Open the 1-pin Primus a few times until you get the hang of what's going on in the lock. Now put a second finger pin, and spring in chamber #2; repeat the previous step until you get the hang of a 2-pin Primus.

Once you feel pretty good about 2-pin Primus, put a third pin set in the lock, but instead of using chamber #3, put the third set of pins in the farthest chamber in the lock. This will let you practice reaching into the back of the lock and manipulating a finger pin that's not so close to you.

Now that you're opening a 3-pin Primus pretty regularly, you're pretty much set.. If you can open a 3-pin Primus, you can open a 5-pin Primus. More pins do not add to the difficulty, only to the time required to open the lock.

Before you jump to a 5-pin lock however, you need to practice with the top stack. Remove all the pins from all the chambers. Put any keypin in the first chamber, and then a standard driver on top of it, and fill chamber #1 for the finger pin. Use your tools to lift the keypin until it sets, you should feel slight rotation on the plug. Then move to the finger pin and lift / rotate like before.

Continue picking and pinning the Primus until all chambers are filled.

My Personal Techniques

I find the hardest part about these locks are actually from the standard driver pins, after picking security pins so much you become accustom to how hard it is to over set them.

If you feel that you have over set a finger pin you probably have, slowly let off of tension until that finger pin has dropped.

The binding finger pin can sometimes be influenced by the rotation of another that has not been set, this is usually because that finger pin has been overset, drop those pins and start over on them.

Most finger pins need more rotation than they do lift, focus more of lifting the pins very slowly, and rotate one end to the other. If the finger pin pick has an angle to its push/pull walls it may also lift the finger pin as you are pushing or pulling missing the gate.