Mosler 302

[Oldfast]

BREAKDOWN


Mosler MR 302

Group 1R ... 3 wheel ... hand change ... spring loaded fence

Wish I was posting this in Oldfast: Safe Chronicles as a successful manipulation, lol... but that's gonna have to wait.
In fact, I'm not even all too qualified to be talking much about this lock. Instead, I'll simply present some photos
& point out some of the features we're dealing with Mainly, my hope is to stir up some good discussion here.





Upon removing the back cover, we can take note of several things....

First, a friction plug. You see the white circular piece of delrin within the wheel post? It is spring loaded
and presses firmly up against the spline key. Just as the name implies, it creates friction when turning the dial
and effectively reduces feedback. Again, thoughts are welcomed - as this friction plug may serve another purpose.


Next, you may have already noticed the additional piece behind the drive cam.
We'll take a look at this manipulation resistant drive cam in a moment, but first....

These locks are known mostly for the wheel design. The back side of each wheel helps combat
radiological attacks. If x-rayed, the design is such that each wheel will appear to have 16 gates.



Most interesting to me as a manipulator though, is the outer edge of these wheels:
Each wheel is comprised of 16 major flats & 16 minor flats... creating a 32-sided wheel.



The obvious intent behind such a design -- interfere with manipulation attempts.
Graphing such a wheel will result in something resembling the Appallachian mountains. lol

So I did my homework while waiting for these locks to arrive. I was fully prepared to deal with
this type of wheel. However, there was something within these that I was NOT expecting.......

......this particular model is equipped with Mosler's manipulation resistive shutter driver.



This little work of art sets upon a heavily spring loaded bearing within the lock body.




This creates two very distinctive 'clicks' that can be heard and felt each time the dial passes this area.

The two pieces are spring loaded and, to some extent, will move seperately from each other. In other words;
the bearing in the lock case will catch and temporarily hold the shutter driver. Meanwhile, the drive cam will continue
rotating. When enough pressure builds up, the shutter driver snaps free of the bearing and catches up with the drive cam.


The shutter driver is designed to defeat manipulation attempts using audio instruments. And I can tell you...
from the brief amount of time I've spent with this lock: it really does a FINE job of masking the contact points.
However, I've been informed by more than one credible source... that these locks can indeed be manipulated.




A truly marvelous mechanism. Although the manipulation of it may elude me at this point... I'm more than happy
to simply appreciate it for now. Also, this lock cleaned up nicely and treated me to an amazing transformation.



I very much welcome ANY thoughts, questions, history, or info you'd be willing to share/add about this lock. THANKS!

For example.... this is the first time I've seen a 'forked' spline key. Maybe the design of it,
coupled with the friction plug lessens the chances of a malfunction and a possble lockout?

[Altashot]

Beautiful write up Oldfast.

I have seen X-ray proof locks before but nothing like this one.
At first, I wondered why "The bolt must be out to remove cover", then I saw how the fence lever pivot screw interlocks with it when in the unlocked position. I guess it is to prevent someone that has access to the safe but not the combination to inconspicuously remove the cover to decipher the comb...?
That "friction plug", is it a spring loaded plunger that presses the dial/spindle/drive cam assembly outward directly via the spline? If so, could it be to assure the spline key never falls out and/or to assure that the "shutter driver" engages with the spring loaded ball bearing effectively? I noticed the re-locker too, I've never seen that type.
That split cam is something else, I can see how the cogs catch on the ball and yet still allow the cam to turn to build spring pressure that overcomes the ball bearing spring. I bet it camouflages the contact points very well with its clicks and sudden releases...
Speaking of the cam, Does this clickety click mechanism assist in throwing the bolt at all upon locking? If so, does it auto scramble too?
I am not a fan of "hand change" combs but this one seems to be very well made.
I don't like plastic in any locks either...But to meet the radiological resistance, I guess it has to be

Really cool lock, something that was made to meet some very strict requirements. Probably a Government or some Embassy...

thanks for sharing!

M.

[keymaster1053]

Hey Oldfast,
Great Writeup. I'm thinking that the horseshoe spline key was used, because of the friction plug. it would seem to me that if you used the standard "L" spline key, the sharp end of it, over time may dig into that friction plug and create problems? what do you think?
As far as the "302 Click, Click" as it is affectionately known in the industry, it can definately be manipulated, as I have a friend that manipulated EVERYTHING my boss gave him to open when we worked together years ago. my boss even went so far as to loosen the drive cam on the 302 before he gave it to him to open, so the dial was real sloppy. he still got it open! so I guess it comes down to practice, practice, practice!
let us know how it goes!
Jim.

[MrAnybody]

Yet another gorgeous Oldfast writeup. Can't beat em

While I've got nothing to add on the lock itself, I just wanna say many thanks for sharing. It's such a pleasure to see.

[ARF-GEF]

Oldfast do you have any guess how old it might be? I know Mosler went out of business, but on the other hand the plastic wheels always look rather modern to me.

[gfunx]

Beautiful pictures as always. Could you do me a favor and post the patent numbers when you get a chance? I couldn't quite read them from the picture of the back cover.

As far as it looking modern, I believe the lock was made from the early 60s to early 90s. It was designed for DOD/military applications. Very nice lock.

[MBI]

Some very clever engineering there. It's enjoyable to see examples of the escalating "arms race" between lock makers and lock breakers.

[Blacky]

Nice lock for safe?

look good thanks

[Oldfast]

Beautiful write up Oldfast.

Thank you much. I only wish I knew a little more about it. All in due time I guess.

At first, I wondered why "The bolt must be out to remove cover", then I saw how the fence lever pivot screw interlocks with it when in the unlocked position. I guess it is to prevent someone that has access to the safe but not the combination to inconspicuously remove the cover to decipher the comb...?

Makes sense. I would agree. I can't really think of any other possible reason for such a feature.

That "friction plug", is it a spring loaded plunger that presses the dial/spindle/drive cam assembly outward directly via the spline?

EXACTLY

If so, could it be to assure the spline key never falls out and/or to assure that the "shutter driver" engages with the spring loaded ball bearing effectively?

At first I thought it was another security feature, but I think ya hit the nail on the head here.
More so than impeding manipulation, I think the system is in place to ensure proper function.

I noticed the re-locker too, I've never seen that type.

The low density wheels are probably susceptible to heat, but so too is the relocker. Kinda evens out I guess. lol
Notice the corresponding brass pin on the lock cover that depresses the re-lock trigger; this pin is held in place
by a thermal link metal. If the lock is attacked with heat, it will sink into the cover and activate the relocker.

That split cam is something else, I can see how the cogs catch on the ball and yet still allow the cam to turn to build spring pressure that overcomes the ball bearing spring. I bet it camouflages the contact points very well with its clicks and sudden releases...

Indeed it is With the bearing holding the shutter driver in place... I AM able to move the cam over and passed
the contact point WITHOUT the release/snap of the shutter driver. Placing the bearing in the other indent allows
me to do the same with the other contact point. But still, I'm unable to detect much of anything. You can see in
my second picture how, even at the point of contact, the lever nose still rides on the shutter driver. Good stuff

Honestly, my normal 'patience of Jobe' seems to be a bit depleted after this summer work season. lol
My peaceful hibernation deep into the winter might be the best time to give this one another shot. ha.
But for now, it's a beautiful lock that I'm very pleased to place into my small (but growing) collection.

Speaking of the cam, Does this clickety click mechanism assist in throwing the bolt at all upon locking? If so, does it auto scramble too?

No, and no. After dialing the combo, the bolt can be extended and retracted multiple times.

Really cool lock, something that was made to meet some very strict requirements. Probably a Government or some Embassy...

I know these, and several other models of the 302-402 were used on government safes & containers for a number of years.
When exactly these became 'out-dated', I'm not sure... but I know it wasn't all that long ago when they stopped using them.

[Oldfast]

Great Writeup. I'm thinking that the horseshoe spline key was used, because of the friction plug. it would seem to me that if you used the standard "L" spline key, the sharp end of it, over time may dig into that friction plug and create problems? what do you think?

Thanks Jim. And yeah, I'd say with a forked spline like that, it not only gives you a smooth surface, but a solidly seated spline
key that's utilizing 2 of the grooves on the spindle rather than just one. Couple that with the constant pressure applied from
the friction plug... the entire design just seems to create for a good, sound, and reliably functioning mechanism.

....As far as the "302 Click, Click" as it is affectionately known in the industry, it can definately be manipulated, as I have a friend that manipulated EVERYTHING my boss gave him to open when we worked together years ago. my boss even went so far as to loosen the drive cam on the 302 before he gave it to him to open, so the dial was real sloppy. he still got it open! so I guess it comes down to practice, practice, practice!
let us know how it goes!

Very impressive.... AND encouraging! It's the frustrating ones that can really turn me on I guess. LOL. I'll give it my best.

[Oldfast]

Yet another gorgeous Oldfast writeup. Can't beat em

While I've got nothing to add on the lock itself, I just wanna say many thanks for sharing. It's such a pleasure to see.

Thanks so much. Always so nice to be around some fellow lock-porn addicts that can truly appreciate it
No one else wants to listen to me ramble on. Well, my girl listens... but does she really have a choice? LOL

Oldfast do you have any guess how old it might be? I know Mosler went out of business, but on the other hand the plastic wheels always look rather modern to me.

Sadly I do not. Maybe the Serial # or one of the patent #'s will reveal more?
I know you're quite a collector (haven't forgot about a possible trade this winter, btw)
..... does your collection include/focus much at all on safe locks?

....Could you do me a favor and post the patent numbers when you get a chance?....

No problem... I'll post the #'s when I get home tonight.
Do share any interesting finds you may come across?

Some very clever engineering there. It's enjoyable to see examples of the escalating "arms race" between lock makers and lock breakers.

Isn't that the truth. Always interesting. I'd say they compliment each other quite nicely. LOL

Nice lock for safe?
look good thanks

Exactly right. For a safe or chest of drawers. Glad you like!

[Oldfast]

....Could you do me a favor and post the patent numbers when you get a chance?....

No problem... I'll post the #'s when I get home tonight.
Do share any interesting finds you may come across?

So the tag says.....

PROTECTED BY ONE OR MORE OF
THE FOLLOWING US PATENTS

3, 699, 789
3, 702, 551
3, 719, 064
3, 727, 439

3, 772, 904
4, 073, 554
4, 230, 912
4, 510, 417

It's right in front of me and I'm STILL having trouble determining a few of the numbers. Hope it's all correct.

[GWiens2001]

Fascinating safe lock, Oldfast. Your explanations and questions/answers are well thought out. Thank you for showing us the breakdown of this lock.

Gordon

[CPT1911]

Thought I'd bring this thread back since there was so much discussion about the Mosler forked spline key and the friction plug.

So today, I finally achieved my first open on my Mosler 302 (Group 2 variant with regular brass wheels). Honestly, I'd only been toying with it to this point because I FOUND THE CONTACT POINTS TO BE VERY TOUGH TO READ CONSISTENTLY. The friction caused by the spring loaded plug made my dial move in a jerky fashion and the exact moment of contact with the cam was very hard for this Newb to detect. When I was learning the lock, I actually sat there like an idiot with the back of the lock held to my left ear and listened for contact because it was so hard for me to feel!

Anyway, Oldfast, you mentioned that the friction plug slowed you down a little in your chronicles...but it really didn't seem like a huge impediment for you. Meanwhile, I found that it caused me tons of difficulty and it was only by SSSSLLLLLOOOOWWWWWLLLLLYYYYY approaching each CP several times that I could read it....

Then I went back to your pics in this thread and the Chronicles and I noticed something...

Take a look at my spline key:

FP.JPG

FP elevated.JPG

Versus the one in your 302s (appears to be the same in the one you manipulated in the Chronicles):

f02f6377-d926-4a15-8cb2-8570708fb491_zpsf59be4f4.jpg

Seems to be quite a bit different!

Lacking your experience, I am not surprised I had a toughter time reading CPs on this lock. But do you think the larger, flatter bearing surface of my spline key added a little more friction and weirdness to the CP readings? If I had to guess, I'd say they originally manufactured the lock with my spline key (which is a more costly part to make), and then realized they could get away with the stamped U shaped spline key and swithched over at some point. Anyway, it is an interesting difference in design that I thought you might find entertaining.

[Oldfast]

Anyway, it is an interesting difference in design that I thought you might find entertaining.

You're right! Very interesting. I'm glad you shared photos! I myself have never seen one like that.
I'd be curious to hear from Altashot as to how many he's come across with a spline key like that.

Anyway, Oldfast, you mentioned that the friction plug slowed you down a little in your chronicles...but it really didn't seem like a huge impediment for you. Meanwhile, I found that it caused me tons of difficulty and it was only by SSSSLLLLLOOOOWWWWWLLLLLYYYYY approaching each CP several times that I could read it....

I have a feeling that your difficulty was not so much a case of 'YOUR sense of touch' versus 'MY sense of touch'.
It may very well be that your lock actually gave you ALOT more friction than mine did. That could be due to the
spline key design or it could just be the lock itself. Every lock is different. Either way, nice job overcoming it!