Angle grinder on forged vs other bolts?

[JHZR2]

I am renewing latches and locks on my new bank of garages. Some of the sliding doors have a 1/4” steel plate heavy latch that an eye bolt goes through and locks. I need to get a new eye bolt.

I know angle grinders are a fast way to cut through locks. The eye hole and the plate used for the latch are large/thick/heavy, so a very large padlock could be used. At some point they’ll just cut through something else that’s weaker. It’s not a high crime area, don’t need fortification, but just want to get the right thing....

So at Tractor supply, they have all sorts of eye bolts, up to 3/4”, and then they have some that are labeled as “super strong” and forged. These sorts of things are usually used for lifting, so locking is a different scenario.

Is there any benefit to getting the super strong forged ones, versus whatever is the regular zinc coated steel one that is thickest? If the forged one is harder to cut, then it’s worth it. If it is no difference to an angle grinder with a metal cutting disc, then I’ll save the $.

Thanks!

 

[Skippy722]

Forging generally makes metal harder to deform, while heat treating to make it hard makes it more difficult to cut. But hard metal is more prone to shattering.

 

[JHZR2]

Ok, somthe forged eye bolts might not be buying me much, at least relative to cutting. Prying may be another story - the old crowbar attack...

 

[Langanobob]

Forged lifting eyebolts might be harder to cut with bolt cutters but an angle grinder won’t have much trouble with one. No quality forged and properly heat treated eye bolt is going to be brittle. A prybar or sledge hammer will damage a cheaper standard hardware store eyebolt long before it will damage a forged eyebolt.

I see gate locks with a steel box over the lock with the only access to the lock being the bottom of the box with enough room to get a key in. Maybe you could adapt something like that without too much expense. Or a locksmith might have some good suggestions?

 

[ABN_CBT_ENGR]

Is there any benefit to getting the super strong forged ones, versus whatever is the regular zinc coated steel one that is thickest? If the forged one is harder to cut, then it’s worth it. If it is no difference to an angle grinder with a metal cutting disc, then I’ll save the $.

Absolute Zero

They are almost all universally forge formed from various steels. The "hardening"/"quenching" is nothing more than for rigidity ( to keep them from deflecting laterally during a properly rigged lift). Its also a surface hardening at that. ( "super" just means a little deeper)

They might make someone sweat for a brief minute with a hand powered hacksaw but any powered grinder wouldn't even slow down

 

[Fattylocks]

Angle grinder won't know the difference.
But for hardware I'd look for a better grade than the bulk they sell at my local farm store. Bought some 9/16-12 nuts and bolts for a project and two of the fasteners failed. Strong like chilled butter. Unbelievable the junk in stores today.

 

[AutoMechanic]

They are all pretty much the same if I remember correctly. All relatively strong too the regular ones would be the easiest to grind or cut most likely. But the forged probably would be harder to cut I’m not too sure.

 

[wpod]

Grinders eat through most alloys like butter.

 

[BlueOvalFitter]

I find this brand of cutting wheel works great for me.

 

[Kestas]

The "hardening"/"quenching" is nothing more than for rigidity ( to keep them from deflecting laterally during a properly rigged lift).

Actually, this is not true. Heat treatment of steel does little to change its elastic modulus. Though it does change the yield strength and ultimate tensile strength. That means heat treated steel will take more force before deflection is permanent. I point this out because this concept is not intuitive to engineers.

Otherwise I agree with the last number of posters that a strong padlock will not resist abrasive cutting more than a softer padlock,

 

[ABN_CBT_ENGR]

Actually, this is not true. Heat treatment of steel does little to change its elastic modulus. Though it does change the yield strength and ultimate tensile strength. That means heat treated steel will take more force before deflection is permanent. I point this out because this concept is not intuitive to engineers.

Negative, It is true and correct in context with the specific subject of an eye bolt as it was used. This is why "eye bolts" are not certified for lifting in most countries and require certified lifting lugs and shackles. It has nothing to do with conventional heat treatment of metals as your comment is directed. ( which is generally otherwise as applied) This is basically a bake and dip. ( with the base metal recipe determining the heat graph on hold downs and all that against its plan loading)

For an eyebolt specifically with a base ( the only ones narrowly approved for official lifting) they are screwed in to where there is parallel contact with the load to be lifted is made ( no exposed thread whatsoever). they are hardened to prevent any deflection whatsoever ( rigidity from the base coming from it not deforming- not the conventional beam calculations for stress) because people have a tendency to lift with the strap/chain at an angle which would otherwise bend the more conventional threaded portion making a potential catastrophic failure likely.

( another reason no PE would ever certify a lift with an eyebolt involved except in very rare circumstances)

I point this out on eyebolts because these concepts are not widely known outside of the people who actually have to certify lifts and the rules that apply and the reasons for them.

 

[Kestas]

Deflection is entirely dependent on elastic modulus. Look up the elastic modulus of soft steel and heat treated steel, compare the two and report back. You'll find there is little significant difference.

My post addressed the original words you chose to post. Perhaps you are considering other nuances of design in your case, such as notch sensitivity. Otherwise I couldn't understand what you were saying about eyebolt design.

Also, to address your original post, heat treatment is not limited to surface hardening. There is also through hardening.

 

[Skippy722]

Yep, I cut a lot of through hardened stainless.... 17-4 gives a beautiful finish when it’s hard.