Problem with CISA oval cylinder

[Woodsmith]

I am trying to pick a CISA oval cylinder, the cylinder is out of the lock, and in situations like this I use a yale key with all the bitting, and top edge of the key ground off as a tension tool, this means I can hold the cylinder and apply tension with the same hand, this has been effective on every cylinder so far.

When my modified key is inserted into the keyway, it hits some sprung resistance about four fifths of the way in. this does not appear to happen when the correct key is inserted, I have also tried regular tension tools.

I am wondering if this is some anti-pick mechanism, or just part of the workings, I appear to be getting the pins to set, but so far no success in opening it! ( methods used so far 1: individual pins, 2 :raking, 3 :snap gun)

Any Ideas?

[EvoRed]

Not sure if CISA cylinders have security pins but I would presume so and it sounds like it, so when all the pins appear set, does the plug turn a few degrees before stopping? If so, and when pushing on the 'security' pin, the plug turns back towards where it started, then yes it's some kind of security pin...

Just push on the security pin slowly, while easing off the tension, allowing the plug to turn back and it should then set and, assuming all the other pins are set, Robert's your Father's Brother, it should pop open...

[Woodsmith]

EvoRed
Thanks for your reply, in desperation I dismantled the cylinder here is what I discovered:

1, The spring resistance is caused by the key actuating a spring plunger device in the plug, this locates into the 'bolt throw', it disengages when the key is removed so that the lock can be operated inside via the thumb turn.

2, There are four spool drivers, and one serrated driver, I'm not sure of the order as I could not use a plug follower.

3, Three of the pins are serrated.

The key bitting is a eye opener too, the two furthest pins are set at the highest bitting, centre pin about half way, next pin lower still, last pin lowest point, from what I have seen on other posts this kind of bitting is more difficult to overcome, and with the drivers I'm not surprised I was having trouble, being a newbie an all!

Still, I now have a better idea of the sort of problems I may encounter with this brand in future, all I have to do now is try and get the B*****D back together again.

Cheers,
Woodsmith.

[EvoRed]

Four spools and a serrated? They certainly have got security pins!

You will feel that spongy feel on most thumb turn cylinders as the thumb turn plug is permanently engaged in the cam. A key being pushed into the key side pushes the follower and spring in so this plug has now engaged the cam too with it's follower...

With no key in the key side the thumb turn plug is engaged only, but with the key also in both plugs are engaged in the cam.

[jason]

CISA are not nice.

When you're trying to put it back together put the key into the cylinder and drop each of the pins into the holes - when they are all level you've got em in the right order

[Woodsmith]

Thanks Jason, I had already sussed that out, my problem is removing the thumbturn plug, I can't see what holds it in the cylinder. It's got to come out to re-load the drivers using a plug follower.
I'm stumped at the moment!

[Chucklz]

Forget about removing the thumb turn. Remove/rotate the cam out of the way. Get a piece of 1/2 inch dowel (or whatever diameter the appropriate plug follower would be) Cut it into a few thin sections so that you can add one disk at a time to "build up" a plug follower.

[toomush2drink]

Search for euro cylinder repinning as a guide has been posted in this section somewhere.