Couple of newbie questions

[cledry]

You guys make a lot of assumptions in this thread. Construction keying is often using small ball bearings, not master pins. And rarely 3 ball bearings in separate positions. I see it all the time......locks that have never been rekeyed often have master pins in them, because the builder may buy all his locks from the wholesaler in one big lot.....they are usually keyed alike in batches for each separate house/dwelling and are keyed to the builders master key so he can get into every place during construction without wasting time.

What assumptions?

You mustn't be familiar with how Kwikset for example does construction master keying. They use 3 ball bearings in place of one master pin in one chamber, the 3 ball bearings take the place of a .025" master pin. The remaining chambers have a master pin of varying lengths. So they use master pins AND 3 ball bearings. I don't think I said they use ball bearings in different chambers, sorry if I confused the matter.

The rest of your statement is simply repeating what others have said about construction keying in this thread.

[cledry]

I think I was wrong that the balls replace a .025" which is a #1 wafer. They instead replace a #2 wafer. The rest still stands they use master pins in the remaining 4 chambers. Here it is explained on a web page. http://www.locksmithcharley.com/builderkey.html

[DanG]

Okay, my new locks have arrived, so I took one of the old one apart (very carefully this time). Here is a photo of the pins and springs from the hull, as well as the plug (pin 5 is on the left, pin 1 on the right)



So, my novice assessment of this is: There are 3 master pins in columns 5, 4 and 3. There was a ball bearing inside the plug in the construction key 'hole' in pin 1. I think the reason my reassembled lock without the master pins still worked is that the master key setup is such that the master key would have deeper cuts than my change key (and consequently, I think this may mean that I could grind my house key and make a master - which as a couple of folks pointed out seems like either a rather incompetent locksmith did this, or they just came that way and the builder never changed them).

I admit I'm a total novice at this, but I want to learn, so any help/analysis from you guys would be greatly appreciated.

[cledry]

Your analysis is correct. It isn't an incompetent keying job though; it is keyed as specified by the manufacturer. You would need 5 keys in order to make a MK though, this is because the ball (which is actually considered a master pin) can be in any of the positions. When you turn your key in the lock the ball bearing will be above the shear line and as the plug turns the ball drops in the small chamber you see next to each pin chamber where it will remain. This effectively drops a single .030" master pin out of the cylinder. The MK now should no longer work.

[minifhncc]

In my opinion I don't think it's wise to use construction key 5 pin locks. I believe they should only be done on locks with 6 or more pins.

I was involved with two houses built by separate builders around the same time. They were both construction keyed by the builders. However, I found out later that the change key for one of the houses worked perfectly (without any clipping) on the other house, after the change key for that house had been used on the lock (and therefore the construction ball had been dislodged).

It was a Gainsborough lock (TE2, 5 pin keyway) which is commonly used by builders here for some reason.