Anyone Removed Brass Padlock Tumbler Caps Via Blowtorch?

[Robotnik]

Odd question: I've heard of a method of rekeying extruded brass padlocks (the ones with small embedded caps over each tumbler) wherein the lock is heated with a blowtorch, then quenched. In trying this out on a scrap Corbin, I was wholly unsuccessful. No movement of the caps to speak of.

Anyone had success with this method? I tried heating the capped area of the body with a propane torch first for two minutes, then five. Quenched immediately in approximately 35 degree water both times. No luck either time.

[RumballSolutions]

Try lightly and repeatedly tapping the area of the caps with a hammer handle or wood mallet. It usually causes just enough movement to show the edge around each cap. Then just very lightly centre punch and drill the cap with a sharp drill bit that is just undersize. Try not to drill too deep or you will break through and have to replace your springs.

You should be left with a very thin, hollow portion of the bible plug or cap (depending on where you come from). Wind in an appropriately sized tap with a t-handle and once the thread bites, use the t handle to pull the cap out.

Much of the time you luck out and the cap starts spinning as you drill. When you pull the drill back, the cap is stuck on the end and using the tap is not necessary.

[C locked]

How would the blowtorch work when both materials are the same
So both would expand/ contract at the same rate.

If it was set screws(steel) in a brass body, it might get some difference in the movement
But then why blowtorch stet screws

[Robotnik]

I'm familiar with locating and drilling these caps, but was looking for a comparably nondestructive method for a specific lock.

Only explanation I can think of for why such a heat treatment would make sense when both body and cap are brass is that the relatively smaller pins cool more rapidly when quenched...but that's a total shot in the dark. Hasn't worked for me, so unless I can confirm with someone, I'll chalk this up to the locksmith equivalent of an old wives' tale.

[C locked]

Id think itd be less of a non destructive method than you think
Enough heat to cause the brass to expand etc would probably anneal the springs,
On the plus side you could probably use a comb pick on it then...

Actually using a comb pick to provide pressure on the springs while quenching might help
Pop the plugs out

[Joshua904]

I've used this technique at work for years to get seized components apart... But it's always been with steel- so no idea on how it would work on brass. Maybe your torch is too big? They make small butane "pen" torches for soldering... I believe for jewelry. I'm only about halfway through my coffee so I can't think of a good way to do this, but you could also try to keep the plugs cooler via heatsink in some way.
If you're just looking to keep it looking unmodified after repinning, it might be be easier to remove them with a drill and recap with some brass rod.

[MatrixBlackRock]

No luck either time.

I have found the easiest way to pull the caps is as already mentioned, drilling them, I have discovered a quick way to locate the caps is to clamp up the lock in a vise and run a fine file over the edge once done the caps will be visible.

Wayne

[adi_picker]

I have tried this a few times on the older style Lockwood 234s (Image here --> http://i14.photobucket.com/albums/a338/ ... ure183.jpg). At first I tried with a Yellow MAP gas blowtorch for about 25/30 mins into regular water, no luck. Then on a butane camping stove for the same time into regular water and got 1 or 2 caps, and the shakle assy cap (Round disc about 10mm in diameter, top side, near the locking dog location). Third attempt was on the butane stove for 40min and into ice cold water, still only 1 more cap. The rest just wouldnt budge.

I have never looked at the temps produced by either gas, but I think it was a pure lack of heat. When I used to work repairing heavy machinery we would get lots of bent panels and beat them back into shape with heat, but the heating time was long, upwards of 30 minutes, and we were using an Oxy / Acet torch, which Im sure would get much hotter than the two heat sources above. Also brass seems to conduct heat very well, so you have to heat all of the lock to get it up to temp. Next time I want to pull one apart, Ill give it another go, but with the Oxy and report back.

I can however attest to the method put forward by Rumball, this is how I have taken many many Lockwoods apart in the past. Pretty much exactly the same method. I use a 3mm drill in the mill / drillpress, and find that the Pin Hole Plugs sold by LAB are a perfect fit. Hammer em in until you have about 1/2mm showing, and then a light file to curve the tops and clean up the area, and no one can tell it aint factory. I havent used a tap as Rimball suggested before for removal, but will in the future, I have almost always had to replace most of the springs. But then springs are cheap, and its better to keep the lock in good nick.

Best of luck,

-adi

[Tyler J. Thomas]

How would the blowtorch work when both materials are the same
So both would expand/ contract at the same rate.

Coefficient of thermal expansion.

When an object is heated or cooled, its length changes by an amount proportional to the original length and the change in temperature.

This is why some locksmiths will drop stubborn cylinders into boiling water and then remove them to quickly shim them. I was perplexed at first until I ran the idea by my chemist friend. The size of similar materials does have a correlation to their thermal expansion. In other words, they don't all expand, or contract for that matter, at the same rate simply because they're the same material.

And, not to nitpick, but the brass caps and cylinder aren't entirely the same.

[kwoswalt99-]

I don't recommend torching locks. I use either a small screw or small screw extractor to take the caps out.

[C locked]

How would the blowtorch work when both materials are the same
So both would expand/ contract at the same rate.

Coefficient of thermal expansion.

When an object is heated or cooled, its length changes by an amount proportional to the original length and the change in temperature.

This is why some locksmiths will drop stubborn cylinders into boiling water and then remove them to quickly shim them. I was perplexed at first until I ran the idea by my chemist friend. The size of similar materials does have a correlation to their thermal expansion. In other words, they don't all expand, or contract for that matter, at the same rate simply because they're the same material.

And, not to nitpick, but the brass caps and cylinder aren't entirely the same.

I understand, and with the difference between materials, i was ignoring the fact that the different mass of the object would affect the transferance of the heat acting under the old phrase
"close enough is good enough"
Assuming the amount of heat required(!when applied by an oxy torch)
would have already melted the brass.

Thank you for correcting my error