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Stretched chain on chain hoist

marka12161

Hot Rolled
Joined
Dec 23, 2016
Location
Oswego, NY USA
I just finished building a nice small rolling gantry crane for the shop. Primary use will be for handling machine accessories (V-heads for horizontal mill, dividing head, shaper & mill vices etc) loading work on and off of machines and other light-duty material handling. I'll be moving hundreds of pounds with this, not thousands so a while ago i bought a nice, compact 1/2 ton spur gear chain hoist of japanese manufacture off of cragslist. This is the perfect size for my needs as it is fairly compact and doesn't have a big wad of chain like my 2 & 3 ton units.

Anyway, I bought it from a guy selling off stuff from an estate sale and paid something like $30 or 40 for it. Well i just got around to hanging it off of the crane and when i tried to operate it, the chain would jam in the "capstan-like thing" over one section of chain. After a bit of disassembly and inspection, it's readily apparent the unit had been overloaded at some point in its life. Links in the effected section of chain (all the way to the hook) do not move freely against each other and have stretched almost an 1/8 of an inch. I considered buying a new length of chain for it but after some consideration, i'm just going to scrap it. The body of the chain hoist may be perfectly fine, or there may be a crack just waiting to propagate while under load (even my small loads) and for $40 bucks, i'm not willing to take a chance. Despite a minor disappointment, it's good to know that these things bend and don't break.
 

sfriedberg

Diamond
Joined
Oct 14, 2010
Location
Oregon, USA
Scrapping is wise. I have no idea if the body could have a hidden flaw, but the chain is absolutely, definitely toast. At $40 you are not out of pocket for much, and the peace of mind is incalculable.
 

hobbyman

Hot Rolled
Joined
Oct 30, 2011
Location
Canada, BC
It is good to see someone taking the right action by disposal. I was in one shop that had several slings with stretched links. Finally someone cut them up and laid them in front of the foreman's door for him to see in the morning. He was not a happy camper but he finally backed down and ordered new chain slings.
Also be mindful that the really strong hardened chains give no warning. They do not stretch. I have seen such a chain fail. I was about thirty feet away and saw the flash of light. We never did find the broken link. Fortunately the load dropped about a foot to land on the truck trailer deck.
 

tdmidget

Diamond
Joined
Aug 13, 2005
Location
Tucson AZ
Yes, scrap it or file a claim with E Bay. The hoist of unknown history but obvious abuse is not worth the chance of injury or damage to the work and/or machine. As noted above , chain gives very little warning and you have yours. This one of the reasons that chain is not preferred as a rigging item. The peace of mind has to be worth a lot and even with new chain you can not have confidence in the abused hoist.
 

partsproduction

Titanium
Joined
Aug 22, 2011
Location
Oregon coast
This one of the reasons that chain is not preferred as a rigging item.

OT, I just wanted to mention that a guy came into my shop once and very seriously told me to throw away my nylon slings, said he'd seen a man die because no one noticed a cut in a sling. So, now that chains are also taboo I guess that leaves cable slings. :D


But for the record I prefer nylon slings, and throw them away when they are damaged. I've seen chain slings try to slide, sometimes pretty fast, off of forks. webbing slings don't do that.

BTW, Harbor Freight sells 110v cable hoists pretty cheap, just double the max weight you'll need it for and buy one rated at that. I bought one to raise and lower a door and it's been very reliable so far 2 years later.
 
Joined
Apr 19, 2006
Location
Manchester, England
One shop I worked at did a lot of work on rubber mill rolls. Usually they weighed in at around 10,000 lbs and could be 12 feet long and 30" or so in diameter.

To sling these rolls we had what we called " Belly Bands ". These were a sort of chain mail mesh fitted to profile burnt ends. One end had a slot in it that you could thread the other through in a choke hitch. The other end had a hole in it for the crane hook. The whole of the chain mesh was coated in thick rubber to protect the finish of the mill roll.

One of my inspector colleagues was miking up the diameter on a roll that had been out for grinding on the top diameter. He had it chest high on the overhead crane. As soon as he had recorded the sizes it was going on a truck and out to the customer. The bearing blocks had been fitted on and were held together with a small chain hoist to stop them moving around.

My pal had just finished miking and was half turning around to put the micro down when the roll just came crashing down with no warning at all ! I was walking towards him to borrow his micro when this happened so I got a good view of it happening.

My pal was shaken but unhurt. The bearing block had a lip on the bottom about 2" wide by 15" long and these lips were buried into the concrete floor.

What had happened was the the chain mesh under the rubber coating had been " fretting " where it joined the profile cut ends and eventually failed. After that we cut away the rubber on all the other " Belly Bands " so this area could be inspected.

Don't take chances with lifting gear , it's not worth it.

Regards Tyrone.
 

tdmidget

Diamond
Joined
Aug 13, 2005
Location
Tucson AZ
It is good to see someone taking the right action by disposal. I was in one shop that had several slings with stretched links. Finally someone cut them up and laid them in front of the foreman's door for him to see in the morning. He was not a happy camper but he finally backed down and ordered new chain slings.
Also be mindful that the really strong hardened chains give no warning. They do not stretch. I have seen such a chain fail. I was about thirty feet away and saw the flash of light. We never did find the broken link. Fortunately the load dropped about a foot to land on the truck trailer deck.
No such chains are approved for overhead lifting. To be approved the failure mode MUST be gradual, ie; the chain must show gradual bending before breaking.
 

john.k

Diamond
Joined
Dec 21, 2012
Location
Brisbane Qld Australia
Thats the difference between gr 80 certified lifting chain and the same tensile "load binder" chain made from cheap carbon steel tempered hard........the certified Gr 80 chain stretches the links until they lock up solid......the hard temper binder chain snaps suddenly,and pieces go flying.............incidentally ,chain hoists generally have a "graduated" link chain ,which is different dimension from standard lift chain (shorter links ,I think) and generally isnt available except in large quantities.
 

Froneck

Titanium
Joined
Dec 4, 2010
Location
McClure, PA 17059
I'm thinking the hoist would not be able to stretch the chain. Something else did like someone putting the 1/2 ton hoist on a 5 ton hoist possibly to add length. So that now not only is the chain stretched the hoist itself has been overloaded and may fail. Might be best to cut it up and save someone else that might get it from a scrap yard or from your trash.
 

DDoug

Diamond
Joined
Oct 18, 2005
Location
NW Pa
I'm thinking the hoist would not be able to stretch the chain. Something else did like someone putting the 1/2 ton hoist on a 5 ton hoist possibly to add length. So that now not only is the chain stretched the hoist itself has been overloaded and may fail. Might be best to cut it up and save someone else that might get it from a scrap yard or from your trash.
The ground clamp fell off the part that they were welding on whilst hanging from said chain hoist.
 

JST

Diamond
Joined
Jun 16, 2001
Location
St Louis
Old thread.

It was my understanding that the hook should open before the chain is damaged. I have an old Yale and Towne 1/2 ton differential hoist. The hook is spread a bit, but the chain works fine on the hoist.

The way the differential hoist is made, the chain has to fit in pockets, which it would not do if stretched.

(I de-rated the hoist arbitrarily to 1/4 of original marking, and it has held up since, hook and all)
 
Joined
Apr 19, 2006
Location
Manchester, England
I was once working very near to a big horizontal boring machine that had a column mounted jib crane for loading the tooling etc. It was a 1/2 ton electrical chain hoist.

All of a sudden I heard a terrific crash from behind me and when I looked around the chain hoist was on the boring machine table. What had happened was the operator, instead of using the jib crane pendant, decided to power the spindle frame upwards to release the chain from a snout bar he’d just fitted. Instead he pressed the wrong button and sent the spindle frame down !

The machine drive was more powerful than the jib crane and the hook at the top of the block straightened and dropped the lot. As you say the chain stayed intact. Nobody was hurt but the operator was a bit shaken.

Regards Tyrone.
 

Joe Michaels

Diamond
Joined
Apr 3, 2004
Location
Shandaken, NY, USA
I've seen wire rope slings and fabric slings fail under load due to damage or misuse (pulling across a sharp corner under load). While none of these failures resulted in injury, the damage done was significant. In industry, we had an 'across the board' policy: if rigging appears damaged or questionable, cut it up so it cannot be used. Misuse of rigging (slings, shackles, lifting eyes, chainfalls, etc) inevitably happens. The next persons to use the rigging are often the ones to discover the damage when inspecting it before use. Plainly, it is not worth taking a chance on questionable/damaged rigging equipment. Inspection of hoists and rigging is one of those things that likely is not done by many people in home shops or small shops. In larger industrial/heavy construction work, inspection of rigging is enforced and anything questionable either is sent for repair (such as heavy chainfalls, which are then re-certified for the load capacity), or scrapped (such as slings, lighter chainfalls, comealongs).

I recall one rigging failure which was entirely preventable. A contractor had used some 'imported' threaded lifting eyes to pick a heavy steel bulkhead gate with a bridge crane. The lifting eyes they used were un-shouldered, and had plain threaded shanks. The eyes were also un-rated (a lifting eye made by reputable firms will have the safe working load or 'SWL' forged onto it). The threads on the shanks of these lifting eyes ended a short distance below the actual eye. The eyes were screwed into tappings in the bulkhead gate (these were 3/4" threaded tappings). To compound matters, the contractor did not bother to screw nuts and washers onto the threaded shanks, which would have provided some reinforcement on the threaded shank in lieu of a forged shoulder. As if things were not bad enough, the lifting slings were 'bridled' at about 45 degrees, and the eyes, as screwed in, did not line up with the face of the eye along the line of load. Load from the slings was applied transverse to the face of the eye. As the load was being raised, one eye failed and the second eye failed within an instant of the first one. The sound of a bulkhead gate, made of heavy fabricated steel plate with wideflange stiffeners and channel steel sides
hitting the concrete floor of the powerplant was probably like a train wreck. The main load block and wire hoist rope of the bridge crane and the bridge crane itself gave quite a jump when load was suddenly let go. It did not take a graduate degree to figure out what happened: the contractor cheaped out on rigging, and bought the cheapest forged steel 3/4" eyebolts. The eyes failed right across the roots of the last threads. No one was injured, and there was an investigation, and it was a 'lesson learned' for that contractor. A swivel type of load-rated lifting eye was what should have been used. Pricey, for sure, but the safe and sure way to rig that kind of load. No damage to the bulkhead gate other than some damaged epoxy paint, and no damage to the bridge crane, which underwent a complete inspection by an independent crane inspector.


The light chainfall in the OP's post is just not worth taking a chance with. Finding chain to fit the chainfall may prove to be a hard proposition as this would be a metric-sized chain, let alone needing to be 'proof chain' rated for hoisting overhead loads. I am surprised, in reading the OP's post, that the hooks on that chainfall had not spread due to the overload condition. One thing we always did at the powerplants was to inspect the hooks by doing dye penetrant or magnetic particle inspection for cracking, as well as dimensional gauging to see if they had spread. The chainfalls coming in from Japan and China are immediately distinguishable by the shape of their hooks. Their hooks are a bit lighter in pattern than US chainfall hooks, and should have spread due to an overload before the chain stretched and deformed. The best thing for the OP's chainfall is a cutting torch and a sledge hammer. At the powerplant, we used to send the chainfalls and comealongs out to a rigging shop for scheduled inspections, service and repair. These were heavier US or Japanese made hoists, from known manufacturers. Parts were readily available, and the capacity (think of a 10 ton chainfall or comealong, or a 20 ton chainfall) was such that it paid to do this. The 40 bucks spent by the OP is a cash outlay, but is 'chump change' when the potential for injury and damage caused by using that chainfall is considered.
 
Joined
Apr 19, 2006
Location
Manchester, England
In the UK all lifting equipment has to be inspected by an insurance inspector by law. Lifting gear - every 6 months. Overhead cranes - every 12 months. These guys are really thorough and go over every link by hand. Any slight cuts on tubular nylon slings - they get cut in half on the bandsaw. Nothing is left to chance. Just as it should be.

Regards Tyrone
 

jmm03

Hot Rolled
Joined
Aug 8, 2004
Location
ventura,ca.usa
When you scrap it disassemble it and throw away the pieces separately. The likely hood of it being recycled again at a scrapyard or picked out of the dump is probably high. Although I have used horrible freight chain hoists for loads under 1/2 ton I remain dubious as to the actual load rating of any chinese equipment. Jim
 








 
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