Combination bicycle locks.

On 6/26/2016 5:10 PM, Jeff Liebermann wrote:
On Sun, 26 Jun 2016 13:50:36 -0700 (PDT), Sir Ridesalot
wrote:

Perhaps the bicyclist just left the lock there so they'd
not have to carry it or so they wouldn't forget it?

I suspect it's a mix of various reasons. I know two of the commuters
involved. Both believe in the 2 lock system for security. Neither
wants to carry the lock on their commute. At home, the bicycle
doesn't need a lock, so it's easy enough to leave it at work. They
would probably keep it in their respective offices, except that they
have to go up the elevator to retrieve the lock every time they arrive
at work. It's easier to just leave it attached to the rack.

One overweight chain lock is owned by a local itinerant bicycle
repairman. His method of operation is to leave various repaired and
to be repaired parts and pieces attached to the racks with a cable
lock, where his customers can pick them up. He has such locks all
over town. Some are marked with his name, but most are not.

There's an awful lot of this going on in Paris at this bridge!
http://www.magazinetimepass.com/wp-c...e-paris-04.jpg

:-)

--
- Frank Krygowski

On Mon, 27 Jun 2016 08:38:57 +0700, John B.
wrote:

You can buy a battery operated 4" angle grinder for $50.00 on e-bay
and titanium cuts about like 304 stainless :-) They also work well for
opening a safe.

I have a Makita 9500D 4" cordless angle grinder.
http://www.makitapowertoolsonline.com/Cordless-Tools/Makita-Cordless-Angle-Grinder-9500D.html
They claim 6500 rpm no load. I've never bothered to measure the rpm
or the power delivered under load, but it's not enough for "bypassing"
locks. The 7.2v NiCd battery is gutless and the depressed center
cutoff wheels have a very limited maximum rpm.

The newer 18v LiIon powered Makita Model XAG01Z 4.5" at 10,000 rpm
might be suitable, but it's looks too big, heavy, and expensive.
http://makitatools.com/en-us/Modules/Tools/ToolDetails.aspx?Name=XAG01Z

Most of the power is lost in the right angle gearbox, so I decided to
build my own. Sorry, no photos or details. I think the unloaded rpm
is about 12,000 rpm, but the delivered power is much more than the
common cordless power tools. The thin abrasive discs I'm using are
rated at about 33,000 rpm maximum. Under load, I measured 25A drain
from a model car battery at 11.5VDC. I can go higher rpm and power,
but I'll need a bigger battery, better bearings, and some way to cool
the motor. Unless I break the cutoff wheel, water (or antifreeze)
mist injection keeps it cool enough to easily double its expected
life.

Or you can buy a "snap gun" for as low as $17 or $18. :-)
https://www.youtube.com/watch?v=y_YgCw4oA00

I've been tempted to buy one of those, but since I consider lock
picking to be a sport, I simply bought a lock picking tool set and a
few cutaway practice locks. If I wanted to do this professionally, I
would probably buy one.

Titanium work hardens nicely when you try to cut it. That's a useful
feature for some applications. It's not very useful when you want to
machine it. I've never had to work with titanium, but I hear its
rather difficult. No clue how it cuts, grinds, or files.

--
Jeff Liebermann
150 Felker St #D http://www.LearnByDestroying.com
Santa Cruz CA 95060 http://802.11junk.com
Skype: JeffLiebermann AE6KS 831-336-2558

On Sun, 26 Jun 2016 21:50:18 -0400, Frank Krygowski
wrote:

There's an awful lot of this going on in Paris at this bridge!
http://www.magazinetimepass.com/wp-c...e-paris-04.jpg

The city ripped it out last year. I would have expected the French to
understand the value of such art (Pont des Arts) but I guess not:
http://www.cnn.com/2015/05/30/travel/paris-love-locks-bridges-feat/
Notice that the Pont des Arts had only a few combination locks as they
might symbolize an easily broken relationship.

Fortunately, the British seem to have taken over after the French
dropped the ball.
http://www.startribune.com/taking-a-cue-from-paris-love-locks-onto-hastings-bridge/384356181/

--
Jeff Liebermann
150 Felker St #D http://www.LearnByDestroying.com
Santa Cruz CA 95060 http://802.11junk.com
Skype: JeffLiebermann AE6KS 831-336-2558

On 6/26/2016 10:49 PM, Jeff Liebermann wrote:

Titanium work hardens nicely when you try to cut it. That's a useful
feature for some applications. It's not very useful when you want to
machine it. I've never had to work with titanium, but I hear its
rather difficult. No clue how it cuts, grinds, or files.

I've never actually worked on the stuff either, but an instructor in our
machine shop lab told of the time that a student mistakenly grabbed a 2"
round bar of titanium instead of the mild steel he was supposed to work
on. The big power hacksaw took some insanely long time to cut through
it, and when he chucked it in a lathe, he kept wrecking high speed steel
tools when trying to cut it, while getting almost no cutting done.

The school's machinist told of machining titanium one day and having the
chips catch fire. Supposedly that was quite exciting.

--
- Frank Krygowski

On 6/26/2016 11:00 PM, Jeff Liebermann wrote:
On Sun, 26 Jun 2016 21:50:18 -0400, Frank Krygowski
wrote:

There's an awful lot of this going on in Paris at this bridge!
http://www.magazinetimepass.com/wp-c...e-paris-04.jpg

The city ripped it out last year. I would have expected the French to
understand the value of such art (Pont des Arts) but I guess not:
http://www.cnn.com/2015/05/30/travel/paris-love-locks-bridges-feat/
Notice that the Pont des Arts had only a few combination locks as they
might symbolize an easily broken relationship.

Fortunately, the British seem to have taken over after the French
dropped the ball.
http://www.startribune.com/taking-a-cue-from-paris-love-locks-onto-hastings-bridge/384356181/

Pittsburgh's got a bridge with a small collection of those locks.


--
- Frank Krygowski

On Mon, 27 Jun 2016 10:03:00 -0400, Frank Krygowski
wrote:

On 6/26/2016 10:49 PM, Jeff Liebermann wrote:

Titanium work hardens nicely when you try to cut it. That's a useful
feature for some applications. It's not very useful when you want to
machine it. I've never had to work with titanium, but I hear its
rather difficult. No clue how it cuts, grinds, or files.

I've never actually worked on the stuff either, but an instructor in our
machine shop lab told of the time that a student mistakenly grabbed a 2"
round bar of titanium instead of the mild steel he was supposed to work
on. The big power hacksaw took some insanely long time to cut through
it, and when he chucked it in a lathe, he kept wrecking high speed steel
tools when trying to cut it, while getting almost no cutting done.

That sounds about right. One of the engineers at a former employer
was making titanium push rods for his VW engine in his spare time. He
claimed that the stock rods were designed to bend, thus limited the
high end RPM. He figured that with lighter and stiffer push rods, he
could get more horsepower out of the engine. He spent about 6 months
cursing the material, but eventually made a complete set. By then, I
was off to another job and never found out if they actually worked and
if it was worth the effort and expense.

The school's machinist told of machining titanium one day and having the
chips catch fire. Supposedly that was quite exciting.

Spark tests for metal identification:
https://www.youtube.com/watch?v=7PWCh6fdXdw
Titanium starts at 4:58.
https://www.youtube.com/watch?v=D094eBa4S7c
Titanium starts at 9:30.


--
Jeff Liebermann
150 Felker St #D http://www.LearnByDestroying.com
Santa Cruz CA 95060 http://802.11junk.com
Skype: JeffLiebermann AE6KS 831-336-2558

"John B." wrote in message
...
On Sun, 26 Jun 2016 15:56:34 -0400, Frank Krygowski
wrote:

On 6/26/2016 1:08 PM, Ian Field wrote:
On Saturdays visit to the supermarket, there was a steel wire
combination lock wound round one of the tie rails with no bicycle
attached.

It took me just a couple of minutes to release it - seriously, does
anyone still buy this crap?!!!

If I find a bicycle slung in the bushes, that lock will do to secure it
till I have time to recover it - but for the bicycle I use, no way!

I wouldn't use one.

But OTOH, what I use almost all the time is a tiny key lock in
conjunction with a thin plastic-coated cable. I suspect any wire
cutters could get through this thing, yet I've never had a bike stolen.

I think the key is to not park a bike in a really vulnerable spot. If
you choose your spot well, almost any lock will do.

You are replying to a fellow who took a week or more to make his
V-Brakes to work (if he ever did) and can open a bike lock "just a
couple of minutes". One can only speculate on how he developed these
skills.

By being smarter than you, stooooopid.

"Jeff Liebermann" wrote in message
...
On Sun, 26 Jun 2016 22:28:32 +0100, "Ian Field"
wrote:

"Jeff Liebermann" wrote in message
. ..
On Sun, 26 Jun 2016 18:08:04 +0100, "Ian Field"
wrote:

On Saturdays visit to the supermarket, there was a steel wire
combination
lock wound round one of the tie rails with no bicycle attached.

It's not from a stolen bicycle. A good bicycle thief doesn't leave
evidence behind, which means he takes the lock, which would be full of
his fingerprints.

A bicycle thief would at best discard the lock by throwing it on the
ground,
and certainly not re-lock it.

As neither of us are likely to be an actual bicycle thief, I suspect
our speculations on the thought processes of a real bicycle thief
might be somewhat lacking. In this case, methinks that you're making
a bad assumption, that the bicycle lock was left attached to the
supermarket bicycle rack for no useful reason. Please re-read what I
scribbled for several good reasons.

It would appear that it's common in the UK, although some people seem
to have found ways to abuse the practice:
http://www.cyclechat.net/threads/leaving-a-lock-attached-to-a-bike-rack-or-similar.95429/

Either way, I've done someone a favour - they're now reflecting on how
lucky
it was their bicycle hadn't been secured by such an easy lock.

I suspect otherwise. My guess(tm) is that a supermarket employee will
arrive to work tomorrow and find their bicycle lock not where they
left it.

The supermarket has secure areas behind locked gates that an employee could
put their bike.

It would be inconvenient - but not as inconvenient as losing their bike
because the lock they used was completely worthless.

They only lost the lock - and learned not to buy another like it - unless
they're as stupid as john.b.

"Jeff Liebermann" wrote in message
...
On Mon, 27 Jun 2016 08:38:57 +0700, John B.
wrote:

You can buy a battery operated 4" angle grinder for $50.00 on e-bay
and titanium cuts about like 304 stainless :-) They also work well for
opening a safe.

I have a Makita 9500D 4" cordless angle grinder.
http://www.makitapowertoolsonline.com/Cordless-Tools/Makita-Cordless-Angle-Grinder-9500D.html
They claim 6500 rpm no load. I've never bothered to measure the rpm
or the power delivered under load, but it's not enough for "bypassing"
locks. The 7.2v NiCd battery is gutless and the depressed center
cutoff wheels have a very limited maximum rpm.

The newer 18v LiIon powered Makita Model XAG01Z 4.5" at 10,000 rpm
might be suitable, but it's looks too big, heavy, and expensive.
http://makitatools.com/en-us/Modules/Tools/ToolDetails.aspx?Name=XAG01Z

Most of the power is lost in the right angle gearbox, so I decided to
build my own. Sorry, no photos or details. I think the unloaded rpm
is about 12,000 rpm, but the delivered power is much more than the
common cordless power tools. The thin abrasive discs I'm using are
rated at about 33,000 rpm maximum. Under load, I measured 25A drain
from a model car battery at 11.5VDC. I can go higher rpm and power,
but I'll need a bigger battery, better bearings, and some way to cool
the motor. Unless I break the cutoff wheel, water (or antifreeze)
mist injection keeps it cool enough to easily double its expected
life.

Or you can buy a "snap gun" for as low as $17 or $18. :-)
https://www.youtube.com/watch?v=y_YgCw4oA00

I've been tempted to buy one of those, but since I consider lock
picking to be a sport, I simply bought a lock picking tool set and a
few cutaway practice locks. If I wanted to do this professionally, I
would probably buy one.

Buy?!!! - I made my own lock pick hook by grinding an old Stanley knife
blade to the required shape.

A Honda motorcycle had sat on the back yard waiting for an engine, by the
time one turned up I'd lost the steering lock key. A narrow strip of
thinnest feeler gauge edged between the lock barrel and body stopped the
pins going back after I'd lifted them with the DIY hook.

Once unlocked, I could take the barrel out and replace the pins one pair at
a time as I hand cut a new key as I went along.

On Sun, 26 Jun 2016 19:49:00 -0700, Jeff Liebermann
wrote:

On Mon, 27 Jun 2016 08:38:57 +0700, John B.
wrote:

You can buy a battery operated 4" angle grinder for $50.00 on e-bay
and titanium cuts about like 304 stainless :-) They also work well for
opening a safe.

I have a Makita 9500D 4" cordless angle grinder.
http://www.makitapowertoolsonline.com/Cordless-Tools/Makita-Cordless-Angle-Grinder-9500D.html
They claim 6500 rpm no load. I've never bothered to measure the rpm
or the power delivered under load, but it's not enough for "bypassing"
locks. The 7.2v NiCd battery is gutless and the depressed center
cutoff wheels have a very limited maximum rpm.

You must have an older one as the new Makita is 10,000 RPM.

Use the 1mm thick flat wheels. I can cut 1/2" steel bar in (probably)
less than 30 seconds.

The newer 18v LiIon powered Makita Model XAG01Z 4.5" at 10,000 rpm
might be suitable, but it's looks too big, heavy, and expensive.
http://makitatools.com/en-us/Modules/Tools/ToolDetails.aspx?Name=XAG01Z


Most of the power is lost in the right angle gearbox, so I decided to
build my own. Sorry, no photos or details. I think the unloaded rpm
is about 12,000 rpm, but the delivered power is much more than the
common cordless power tools. The thin abrasive discs I'm using are
rated at about 33,000 rpm maximum. Under load, I measured 25A drain
from a model car battery at 11.5VDC. I can go higher rpm and power,
but I'll need a bigger battery, better bearings, and some way to cool
the motor. Unless I break the cutoff wheel, water (or antifreeze)
mist injection keeps it cool enough to easily double its expected
life.

Are you talking about the life of the grinding wheel? If so I buy the
4" x 1mm disks for something like a dollar or maybe a few cents more,
a piece.


Or you can buy a "snap gun" for as low as $17 or $18. :-)
https://www.youtube.com/watch?v=y_YgCw4oA00

I've been tempted to buy one of those, but since I consider lock
picking to be a sport, I simply bought a lock picking tool set and a
few cutaway practice locks. If I wanted to do this professionally, I
would probably buy one.

Titanium work hardens nicely when you try to cut it. That's a useful
feature for some applications. It's not very useful when you want to
machine it. I've never had to work with titanium, but I hear its
rather difficult. No clue how it cuts, grinds, or files.

It does work harden - very quickly. With a sharp drill and an
experienced "operator" you can drill it about the same as stainless.
BUT, if you let the bit slip, even as little as one revolution, you
end up with something that is "hard as glass".

But hard or soft it grinds about the same and cutting it with a 1mm
cutoff wheel is not really a big problem.
(Been there, done that)

--
cheers,

John B.