Simple preventive against bump keys...

Seems to me that splitting one of the top pins into two pins should do it, since only the uppermost pin would bounce up,

not really.. seems another method might be a bit more 'resistant'..

gotta watch the upper pin height carefully I would think, so you didnt create an 'incidental master'

--Shiva--

Well,...the "lower" top pin would have to cover the shear line, so the upper edge of it would be over the shear line anyway.

In and of itself probably not, although it might help slightly, it does not overcome the physics involved. There might be some benefit to playing with the point style on the pins. Try this, set up a cylinder with an assortment of traditional pointed pins, some Kwikset bull nose pins and one or two chambers with Russwin ball bearings and flat bottom pins.

By doing this you may be able to achieve enough timing variation so that if a person were to try to bump the shear line gap would be blocked by some pins on the down stroke while others were on the up stroke. You may have to spend a little time when generating change keys to accommodate this scheme by making a rounded cut for the balls a wider cut for the bulls and a standard cut for the points but you should end up with a smooth working key and a more difficult to bump lock.

1. Use good springs (Major Mfg TRS-250 tangle resistant one's are nice)

1. Use the correct height drivers, not all shorties

2. Use spool and/or serrated drivers

1. Sell the customer a better lock with sidebar or other secondary mechanism

But not where the secondary mechanism is 'keyed alike' as in ASSA (or derivatives such as Australian Lockwood twin) or Schlage Primus, as found in universities and the like or region covered by a prominent locksmith shop. Any stray related key can be made into a bump key with a reasonable chance of working.

I've now tried my "solution" on three different locks, and it works fine. Just stretch a couple of springs...

Obviously, a locksmith would rather replace a cheap Kwikset with a Schlage Primus - but the fix works fine on the Kwikset.

good point "peterwn".

my2¢

I tried the stretched spring solution on a couple of locks and it worked fine. However, every lock and every bump key (with its own unique ramp and height of teeth) is a unique combination. Has anyone else tried this simple technique? If so, what results?

Thanks,

So you can't (according to you) bump key it but anyone with a clue what they are doing can still pick it faster than I wrote this, so what's the point?

Anyone tried pushing two springs together, side to side? So that you could put a double spring in the top chamber?

Or mix brands of springs, so they have different power.

I've only once had someone ask me about making cylinders more bump proof. And never had anyone ask about making them more pick proof. So, perhaps in the real world, it hasn't caught on?

Hey all!

Had a customer with the bump key problem.. (SON) tried the split top pins (added a small top pin above the standard one) I cut a bump key and still got it picked. tried stretching the springs and it slowed me down but the springs didn't keep the tension long and it finally bumped open. last but not least I added a couple mushroom top pins and still got it.. Damn it man! So I did all three methods together and finally couldn't bump 3 out of four locks. Just one gave in. Recommended to the customer I change all the locks to HS.

So the customer is waiting for the tax refund and I'm off to change all the locks!

Roger

The "point" is that any doofus with a bump key ($15 for a set of 6, online) can bump a lock open with no training, no clue. Picking --- now that's another story.

If you load two springs into a lock bad things are likely to happen. I believe that you are running the real risk of crushing the springs or forcing off the cap. There is only so much room and when you have a long pin all of this room is taken up when a high cut is inserted.

True. But you need only *one* long/stretched/doubled spring to bump-proof a lock, so put it where the pin is short.

Stretching out the spring will not take up more space, but two springs will.

They shouldn't really have to ask you. I upsell to many many customers with these el cheapo locks by taking the initiative.

Hardly. Picking a kwikset usually amounts to nothing more than raking which anybody with about 60 seconds practice can do just fine. It's easier than bump keying. BY FAR.