Combination bicycle locks.

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.

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


Here is a quote on machining titanium from a machinist group:

onlinemetals was having a sale so I got a foot of 1/2" titanium round
in "grade 2", whatever that is.

I tried it out on the Sherline lathe. The stuff makes stainless steel
look like brass. Never seen anything work harden as fast, or make such
nasty sharp chips that never break off and just make a brillo pad.

Like the folks on the internet say, as long as you don't interrupt
your cut and don't back off on cutting pressure, it's not bad at all.

The real struggle is always with parting off as everythings wants to
slip out of square on the tiny lathe. I measured the thicknes of the
chip that came off with a HSS parting blade at 0.005 when things we
running OK.

I cut with "relion" cutting fluid, and got a little smoke as Ti gets
hot when cutting as it's apparently a bad conductor of heat.

The stuff takes a decent finish and cleans up real nice with fine
sandpaper if you're real forceful.
--
cheers,

John B.

On Tue, 28 Jun 2016 06:25:08 +0700, John B.
wrote:

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.

It's quite old, back in the days when specifications actually meant
something. Want to buy a megalumen flashlight? My discs are about 2
mm thick. I broke too many of the 1mm variety.

Various locks versus cutters:
https://www.youtube.com/watch?v=pywN558dJaU
Cable locks, about 2 seconds.
Chain, 11 seconds.
U-lock versus battery powered angle grinder, about 5 seconds.
The longest time was 70 seconds for a fancy U-lock.

Are you talking about the life of the grinding wheel?

Yes.

If so I buy the
4" x 1mm disks for something like a dollar or maybe a few cents more,
a piece.

http://www.harborfreight.com/pack-of-10-4-inch-cut-off-wheels-for-metal-45432.html
$0.90/ea in packages of 10. They're cheap enough, but I don't like
changing discs in the middle of a job. Somehow, I always manage to
burn my fingers.

A friend called me from a storage locker facility asking for help. He
had lost the key and didn't have any tools with him. If he didn't get
his stuff out immediately, he would be charged for an extra month. He
has a Ryobi battery powered angle grinder, but not much else. So, I
go to the local hardware store and they're out of cutoff discs. I buy
grinding wheels instead, a big mistake. I then find the angle grinder
has two half dead batteries and the nearest AC for charging is about 5
times as far away as my extension cord is long. I should have driven
8 miles home and returned with the right tools, but I decided to give
it a go with the Ryobi. An hour and two grinding wheels later, I was
getting nowhere. The problem was obvious. Instead a nice narrow 1mm
wide kerf, I was gouging a much larger v-shaped chunk out of the lock.
Then I wore out my 3rd and last grinding wheel, I had removed enough
metal that I could finish the job with a hammer. Incidentally, while
we were burglarizing his storage locker, about 20 people drifted by.
Despite the obvious amateurish and crude assault on the lock, nobody
asked what we were doing or bothered to call the police.

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".

I'm told one also has to use a rather slow drilling rpm.

I'm wondering how well the titanium lock does against and angle
grinder?
Most of these videos say it holds up well:
https://vimeo.com/107618227
but I don't like the way the tools were used.
These videos say that the TiGr lock is lousy:
https://www.reddit.com/r/bicycling/comments/1n13in/the_tigr_lock_is_incredibly_easy_to_break_127/
(5 seconds).

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)

Which means a grinder will work on the TiGr titanium lock.

Well, if titanium isn't good enough, perhaps reactive armor as in tank
armor. For the lock cable, I would use steel or copper tubing filled
with some kind of explosive and some manner of pyrophoric (ignites
when exposed to air) igniter. When someone tries to cut the
cable/tubing, it explodes in their face. As long as the cable/tubing
remains sealed and air tight, it's safe.

Bike Mine:
http://www.gizmag.com/bike-mine-explosive-alarm/43300/
--
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 Mon, 27 Jun 2016 20:55:49 -0700, Jeff Liebermann
wrote:

On Tue, 28 Jun 2016 06:25:08 +0700, John B.
wrote:

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.

It's quite old, back in the days when specifications actually meant
something. Want to buy a megalumen flashlight? My discs are about 2
mm thick. I broke too many of the 1mm variety.


Megalumin? No but I've got an LED flashlight that states "1500W" right
there in white letters on the body. I assume that this means 1,500
watts. and miracle of miracles, it does it with a 3.7 volt, 4800 mAh,
battery. Ain't science wonderful?

Various locks versus cutters:
https://www.youtube.com/watch?v=pywN558dJaU
Cable locks, about 2 seconds.
Chain, 11 seconds.
U-lock versus battery powered angle grinder, about 5 seconds.
The longest time was 70 seconds for a fancy U-lock.

Are you talking about the life of the grinding wheel?

Yes.

If so I buy the
4" x 1mm disks for something like a dollar or maybe a few cents more,
a piece.

http://www.harborfreight.com/pack-of-10-4-inch-cut-off-wheels-for-metal-45432.html
$0.90/ea in packages of 10. They're cheap enough, but I don't like
changing discs in the middle of a job. Somehow, I always manage to
burn my fingers.

Wear leather gloves like the safety manual tells you to :-)

A friend called me from a storage locker facility asking for help. He
had lost the key and didn't have any tools with him. If he didn't get
his stuff out immediately, he would be charged for an extra month. He
has a Ryobi battery powered angle grinder, but not much else. So, I
go to the local hardware store and they're out of cutoff discs. I buy
grinding wheels instead, a big mistake. I then find the angle grinder
has two half dead batteries and the nearest AC for charging is about 5
times as far away as my extension cord is long. I should have driven
8 miles home and returned with the right tools, but I decided to give
it a go with the Ryobi. An hour and two grinding wheels later, I was
getting nowhere. The problem was obvious. Instead a nice narrow 1mm
wide kerf, I was gouging a much larger v-shaped chunk out of the lock.
Then I wore out my 3rd and last grinding wheel, I had removed enough
metal that I could finish the job with a hammer. Incidentally, while
we were burglarizing his storage locker, about 20 people drifted by.
Despite the obvious amateurish and crude assault on the lock, nobody
asked what we were doing or bothered to call the police.

The British Army, I believe has a motto called the 7 P's "Proper Prior
Planning Prevents **** Poor Performance".

As for calling cops :-)

I parked on the main street of Phuket, Thailand and locked my keys in
the truck. Well, I could have broken the window, but it was MY truck
so I was trying to find something that I could slip down beside the
window to pull the lock button up.

I'm down on my knees on the side walk trying to fish the lock with a
24" steel ruler and a Thai guy, good clothes and all, comes along and
says. Oh. Locked your keys in the car?" I, probably a little
embarrassed, say, "Yup". The Thai guy says, "that thing you got isn't
going to work. Wait a minute." He walks off and comes back with a
bicycle spoke with the nipple on it, says, "Here, let me" and reaches
over and pops the lock.

Which, I suppose, in spite of Kipling, demonstrates that the "White
man's burden" isn't always. And bicycle shops sell burglar tools.

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".

I'm told one also has to use a rather slow drilling rpm.

I'm wondering how well the titanium lock does against and angle
grinder?
Most of these videos say it holds up well:
https://vimeo.com/107618227
but I don't like the way the tools were used.
These videos say that the TiGr lock is lousy:
https://www.reddit.com/r/bicycling/comments/1n13in/the_tigr_lock_is_incredibly_easy_to_break_127/
(5 seconds).

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)

Which means a grinder will work on the TiGr titanium lock.

Well, if titanium isn't good enough, perhaps reactive armor as in tank
armor. For the lock cable, I would use steel or copper tubing filled
with some kind of explosive and some manner of pyrophoric (ignites
when exposed to air) igniter. When someone tries to cut the
cable/tubing, it explodes in their face. As long as the cable/tubing
remains sealed and air tight, it's safe.

Years ago we lived a bit outside a town in N. Thailand, in a typical
Thai house, up on stilts, and I kept an old motorcycle under the house
to get back and forth to work. Chained to a post. One night someone
came by with some bolt cutters and stole my motorcycle. Well, I had to
hitch a ride to work and I had to buy another clapped out bike, and
was trying to figure out how to protect my "new" motorcycle.

Since Thai two wire electrical systems have a power and a neutral leg
I reckoned that I could drive a ground stake not too far from the
motorcycle and connect the Neutral leg to the stake and clip the hot
wire to the motorcycle, rubber tires, kick stand on a rubber mat.

I even went so far as to drive a ground rod. Then reality struck, Late
night; wake up; late for work; swill down a cup of hot coffee, burned
mouth; run downstairs; ZAP!


Bike Mine:
http://www.gizmag.com/bike-mine-explosive-alarm/43300/
--
cheers,

John B.

"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.

It could have been left there for a *VERY* useful reason - field testing a
small variety of locks.

The lock manufacturer will always tell the customer that their lock is the
ultimate in security - the reality is usually somewhat different.

If you leave 2 or 3 locks secured to the rail in various locations - you
don't bother replacing any that go missing.

If you've bought a high tech bicycle - losing a couple of locks is far
cheaper.

Jeff Liebermann wrote:
: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. The bike rack in front of a local small office

Assumes that anyone investigates bike theft. Chicago police won't
send someone to take a report, let alone let a detective think about
investigate one. The bike thief could leave his name and address, and
the cops wouldn't care.

:Maybe a Titanium lock?
:https://tigrlock.com
:https://www.kickstarter.com/projects/tigrlock/tigr-titanium-lock-as-cool-as-your-bike/description
:$100 to $200.

20 seconds with an angle grinder takes care of that.


--
sig 8