View Larger Image WWYD? Double-Core Cylinder 32 Comments ⬇ I know there is someone out there reading this who can tell me more about this type of cylinder. How does it work? What’s the purpose? WWYD? Thank you to Darren Patton of Isenhour Door for the photo! You need to login or register to bookmark/favorite this content. By Lori Greene|2019-08-13T10:37:24-04:00August 13th, 2019|Locks & Keys, WWYD?|32 Comments Share This Story, Choose Your Platform! FacebookTwitterLinkedInRedditWhatsappGoogle+TumblrPinterestEmail About the Author: Lori Greene Recent Posts 32 Comments alex sency August 13, 2019 at 8:18 am - Reply hi, it is a Yale bicentric system the upper core is master keyed the lower core is change key only. both cores operate independently of each other. dorms & hotels usage. Kevin Lach August 13, 2019 at 9:10 am - Reply https://www.lockpicking101.com/viewtopic.php?f=9&t=15842 Charles a August 13, 2019 at 9:48 am - Reply One a tenant key And one a security/ owner key?? Like with some Knox devices:; https://www.knoxbox.com/store/files/KnoxVault-4400-Dual-Lock-Spec-Sheets-W.pdf Travis Anteau August 13, 2019 at 10:19 am - Reply I assume it would be the same as this padlock: https://www.antique-locks.com/showthread.php/1988-Yale-Bicentric-padlock email@example.com August 13, 2019 at 10:51 am - Reply Information on this type of locking system can be found here http://www.1st-net-lock-museum.com/ot2.htm Jon McKinney August 13, 2019 at 1:05 pm - Reply Looks like someone tried to key and IC core and didn’t know what they were doing. Ronald Betschman CML,CFDI August 13, 2019 at 3:07 pm - Reply Yale duplex is one manufacturer. It allows master keying on two different keyways and does not even have to be in the same family of keyways. Jerry Richmond AHC/CDC (retired) August 13, 2019 at 3:10 pm - Reply I think I can at least identify it for you. Looks like an old Yale bicentric cylinder. In my 44+ year career, I only knew of one local utility company that used these on their facilities and sub-stations. We did not move much Yale product in our area and I’m retired, so I’m sure someone else out there has more detail about the intricate workings of this cylinder. Glendrick August 13, 2019 at 3:11 pm - Reply I found a little information online, but not much. https://www.lockpicking101.com/viewtopic.php?f=9&t=15842 Dave Snell, AHC August 13, 2019 at 3:13 pm - Reply It is a Yale Bicentric Cylinder. I don’t remember exactly how it works but it was for very large Grand Master Key Systems. Angie August 13, 2019 at 3:18 pm - Reply Is it for a secure room that requires 2 people’s keys to enter? Joel Niemi August 13, 2019 at 3:36 pm - Reply work-around for two different masterkey systems? Randall Oxley August 13, 2019 at 3:40 pm - Reply This is a Yale Bicentric cylinder that is keyed for a master key (or keys) and a change key, each with it’s own keyway. It was designed for extremely large master key systems and long use. The two keyways are fitted with gears on the back end and they provide different operating functions. Ken Adkisson August 13, 2019 at 3:43 pm - Reply Back in the late 70’s and early 80’s, a hotel I was working at used a similar type cylinder with two keyways that was made by Winfield. If I remember correctly, one keyway was a guest key and the other was for housekeeping and security. Chad A Jenkins August 13, 2019 at 3:56 pm - Reply The top cylinder is a master override. Kwikset made a line of these too. Harry August 13, 2019 at 3:58 pm - Reply Would assume a security door where 2 keyholders need to be there to unlock the door. firstname.lastname@example.org August 13, 2019 at 4:32 pm - Reply Hi Lori. That’s a Yale Bicentric cylinder. These were available as rim or mortise cylinders, essentially it’s two cylinders in one shell. From the master keying perspective it’s similar to the master ring cylinder in that the change key and the master keys were independent of eachother, but with the bicentric they could even be different keyways. If you search Yale Bicentric you can probably find a picture of the exploded view Ronald Betschman CML,CFDI August 13, 2019 at 5:04 pm - Reply Also known as a Bi-Centric cylinder. Approx. 1924 according Billy Edwards(retired key systems manager for Yale,Medeco and Master) David Federico August 13, 2019 at 5:12 pm - Reply These were used in large master key systems . The bicentric core allowed the unique master key to open the cylinder using it’s own keyway or core as it were . It allowed for more change key bittings . The back of the cylinder has two interconnecting gears that operate the cam or tailpiece allowing either core to operate the lock its installed in David Federico August 13, 2019 at 5:16 pm - Reply Most of these lock cylinders are obsolete now however Weiser has just reintroduced this configuration in there so called smart key systems in order to allow for “Master Keying “ Chuck Park August 13, 2019 at 6:17 pm - Reply That’s an old Yale Bicentric. Each cylinder plug operates independently of the other to turn the cylinder cam, allowing two different keys to operate the lock. In it’s heyday, they could be ordered with the same keyway, or different keyways in each cylinder plug. Here is a picture that shows the gear drive for the cam: https://preview.redd.it/i8vj5knakmj01.jpg?width=640&crop=smart&auto=webp&s=22fcfb7109eafc047571eca0b456d68acef51c58 André Robichaud August 13, 2019 at 10:00 pm - Reply That cylinder is a Yale bicentric. They were used as a master key system where the master used one plug and the change key, the other. You can have masters that are on a completely unrelated keyway system than the change keys. These cylinders have two superposed cams, the upper keyway operating one of them with a set of gears. I believe they are no longer in production, the standard split-pin master keying having superseded it. Howard Krutzler August 13, 2019 at 10:20 pm - Reply Howdy, Howdy Lori, I believe you have access to clearstar.com In the archives / search section, type in dual cylinder, or dual plug, or bicentric, or yale bicentric for discussions, photos and so on, there were different functions Howard Krutzler August 13, 2019 at 10:40 pm - Reply Howdy Again Lori also google Yale Bicentric, yale bicentric mortise lock, yale bicentric mortise cylinder http://www.simon-says.net/lds3/vt_build_me_one.htm https://www.lockpicking101.com/viewtopic.php?f=9&t=15842 and so on Peter Schifferli August 13, 2019 at 10:40 pm - Reply Looks like an old Yale ‘Bicentric’ cylinder, an early alternative to split-pin masterkeying where the change key was used in one plug and the master key in the other. The current Kwikset SmartKey key control deadbolt uses a similar system with two lock plugs, one of which is concealed. Less common were Yale dual custody versions where two simultaneous keys were required to operate the lock. Howard Krutzler August 13, 2019 at 10:47 pm - Reply Howdy again, a little more Winfield https://www.google.com/search?q=Bicentric+Mortise+Lock&client=firefox-b-1-d&tbm=isch&source=iu&ictx=1&fir=RSwDJKaDF3L2-M%253A%252C7tYrOg0i2nITvM%252C_&vet=1&usg=AI4_-kRAEmCnVv2JZ0RiS7fKCb413tWY4Q&sa=X&ved=2ahUKEwj3nMzsq4HkAhWK4FQKHXoaC68Q9QEwAXoECAYQBg#imgrc=k-CtwiljGkEMAM:&vet=1 https://patents.google.com/patent/US4069694?oq=4069694 Howard Krutzler August 13, 2019 at 11:05 pm - Reply Yale Catalog # 26 from the Internet Archive a great site, If i recall Yale produce Bicentric cylinders into the 1990’s, https://archive.org/details/YaleCatalogNo.26/page/n37 https://archive.org/details/YaleCatalogNo.26/page/n257 https://archive.org/details/YaleCatalogNo.26/page/n401 Charles a August 14, 2019 at 12:01 am - Reply Modern day:: https://www.kwikset.com/smartsecurity/key-control.aspx RB August 14, 2019 at 9:10 am - Reply Clearly this is for the missile launch scene at the beginning of the movie “Wargames.” Both guys in the silo need to turn their keys simultaneously. (kidding) email@example.com August 14, 2019 at 1:15 pm - Reply Most of the above is correct but want to add some detail. I have not seen these as mortise cylinders which are dual custody but they may exist. Usual case is as described where end user gets a key using one keyway and the others get a key using the other. They were used in very large systems and allows more layers to the master key system. Both keyways could be master keyed in the usual progression system. The use of a different keyway meant an end user could not escalate authority to learn the other levels using the other keyway. With a 6 pin Yale key, it is easy to get 3 levels of master key per cylinder so the system could handle 6 layers if wanted. I doubt this was often done but it could. David Federico S.H.C. T.C.P.L. AAADM August 14, 2019 at 7:18 pm - Reply Well Lori looks like you got your answer. Lol seems there are still a few of us that have worked on and remember this product. Oldies but goodies Richard Howard AAADM CFDAI CRL DHT IQP April 13, 2020 at 8:04 pm - Reply Really great answers. Isolating the TMK bitting from the from the pin stacks to me is the real payoff for the B-Centric or Master Ring or Duplex platforms. In 2 – step systems, when you do not loose the TMK in your KBA the quantity of your theoretical changes is at its maximum. Leave A Comment Cancel replyComment Save my name, email, and website in this browser for the next time I comment. Don't subscribe All Replies to my comments Notify me of followup comments via e-mail. You can also subscribe without commenting.