Cutting 16 mm hardened steel with hacksaw

[Tim King]

Clearly an angle grinder would be one of the best tools to cut a 16 mm hardened steel. But my budget is limited.
If I had to use a hacksaw, could anyone recommend a blade? Would it be better to use 14 TPI or 24 TPI?

More importantly, how long does it take to cut through? Like 10 minutes? or 60 minutes?

P.S. I lost my keys to my bike lock recently.

[Bill Dufour]

The more teeth the better. Here the bike thieves freeze the lock, maybe liquid N, then hit it with a hammer.

[Mel Fulks]

I have a neighbor who has a real estate lock box on their railing. Realtor says it's broken , I'm going to grind It off with my Harbor Freight disk grinder. It's been used several times,but still works.

[Roger Nair]

Can the cylinder be drilled out?

[Bill George]

Trust me, buy a 4 1/2 inch angle grinder with a 5/8 arbor new ones can be had for less than $20 off Harbor Freight or else where. You can get off Craigslist used also. Buy a abrasive cut off wheel(s) and the 16 mm hardened steel will be cut in less than a minute. Yes you will need safety glasses. A hacksaw blade will not touch. I cut two locks off my wife's bike on two separate bikes, longest one took a full 60 seconds.

[Mark Wooden]

You can try a carbide grit covered hacksaw blade, a regular one won't touch it. But it will probably take a long time. +1 with Bill's suggestion

[Tim King]

Can the cylinder be drilled out?

Interesting idea! I do have a hand drill. But I am not convinced that the latch bolt would move even if the cylinder is completely drilled out. Are you sure?
The bike lock I have has the disk detainer type of cylinder. Also I was actually considering to pull out the disks from the keyway by using a threaded screw. But I figured it might not that easy after I saw an online photo of an attempted cracking of that kind of lock.

[Roger Nair]

If the lock has a brass cylinder and a common keyway, drilling out the cylinder should disable the lock. The big but is this is a suggestion not based on observation nor deep experience.

[Bill Dufour]

Note that drilling out a cylinder does not need to be full diameter. All you need to do is disconnect the cylinder from the cam on the back end. A 1/4 or 3/8 drill should do it.
Bill D.

[Bruce Wrenn]

+1 on the HF $9.99 angle grinder. Add a Lenox diamond cutting wheel (about $15 at Lowes,) and you are ready to take on the world.

[John Lanciani]

Location? Chances are good that someone here will loan you what you need if you are close by...

[Mike Trent]

Here’s an alternative suggestion: Take locked bike to a locksmith. A friend of mine is one, and he popped the trailer hitch lock off of my truck, after I lost the key. It was the circular style lock you typically see on bike locks, vending machines, etc. He picked the lock in under a minute, and I gave him $20 for his troubles.

[Tim King]

Here’s an alternative suggestion: Take locked bike to a locksmith. A friend of mine is one, and he popped the trailer hitch lock off of my truck, after I lost the key. It was the circular style lock you typically see on bike locks, vending machines, etc. He picked the lock in under a minute, and I gave him $20 for his troubles.

LOL, I called them a few days ago. The one in my area (NYC) asked 29 bucks just for coming to the site to "take a look". The actual lock-picking price goes from there. So I would rather get an angle grinder if I have to.

// My bike is locked to a bike rack in a public area.

[Tim King]

If the lock has a brass cylinder and a common keyway, drilling out the cylinder should disable the lock. The big but is this is a suggestion not based on observation nor deep experience.

Thanks! Also thanks goes to @Bill D.

Let me try this next week. And very likely I will come back to let you guys know how it goes.

[Brice Rogers]

The HF angle grinder is a good idea. I had a Master lock with a hardened shaft that needed to be removed. I tried a hacksaw and it just "skittered" over the shaft. I tried for 2 or 3 minutes. It looked like it shined up the shaft/hasp but didn't even scratch it. So at that rate it appeared to be a several year operation. If I recall I either used my AC welder cranked up or used an oxyacetylene torch. I recall that the lock was in 2 pieces in about 5 seconds.

[Bill Dufour]

You can also buy a cordless angle grinder for less money then calling a locksmith.
Bill

[Ted Phillips]

It would be a lot more fun to get a flask of liquid nitrogen and a sledgehammer...

Just sayin'...

[Peter Kelly]

The Home Depot on 23rd street has a selection of cordless angle grinders. Otherwise the nearest HF is all the way down on Goanus..

[Floyd Mah]

Check to see if there is a tool lending service at your local library that can loan you an angle grinder. I recall the first time I tried to cut hardened steel with a Sawzall. The steel took the teeth off the metal-cutting blade in no time flat. Otherwise, I'm all for the HF grinder. Less than $15 and you also have a tool that can be used later on.

[Tim King]

I thought about drilling out the cylinder, however, I did not bother to make the effort to attempt as I suspose the disk-detainer type of locks are designed for protecting from drilling.
Eventually, I got a brushed cordless angle grinder of 6500 rpm from Home Depot. With a metal cut-off wheel, it took about 90 seconds to make a single cut. Then I was able to rotate the cut shackle to release my bike free. (I thought I had to make two cut).
(I was only considering to give it a try with this cheap brushed grinder with the default 1.3 A 18 V battery, and thought that I might have to upgrade to 10000 rpm brushless one with 4A battery. But it worked. And with this battery of only 1.3A, it can even last for 8 - 10 minutes under load based on antoher test afterwards.)
// Pretty funny, I was cutting the lock in busy hour of the day right outside the main entrance of a large building, huge noise and sparks drew no attention at all to passerbys. Only a security guy in that area approached in the middle of my cutting and smiled at me "Cutting your own bike?", I said yes, When he was about to leave, I voluntarily showed him my Amazon orders of the bike lock and tire as the only evidence I can eaisly get to prove the ownership.