Using Threaded eyebolts

By ctacker (****)

Date 11-13-2008 21:41

I would think you could get a forged nut to match the strength of the eyebolt.
Remember also that when using a shouldered eyebolt at 45 deg. angle you should only be lifting 1/4 of the rating for the eyebolt and your load angle factor is 1.414 for a 45 deg angle.

Carl

By aevald

Date 11-13-2008 22:07

Hello Bill M, my response isn't based on any codes, laws, or other specifications that I could quote to you. I would , however, say that using the eyebolts you have described for lifting anything other than a straight up lift at the rated working load could be a bad idea. I am also saying that this isn't an uncommon practice for many situations by a lot of different folks, I have seen it enough to know that.
In most instances, the eyebolts that you are referring to are commonly found on many electric motors, gearboxes, and any number of other industrial products. They are very well suited to these purposes and in most instances I am pretty sure that their applications for these uses are very much over-kill with regard to loading/weight. Using them for other lifting tasks could set yourself up for some serious consequences regarding safety and liability. In particular, if the individual who is using these items doesn't have a clear understanding of their load ratings and also the orientation of the loops on the tops of these while they are being used, they could be in for a serious accident or failure. You spoke of using them up to a sling/chain angle of 45 degrees. If the orientation of the eye isn't in-line with the lift you could see a tearing or shearing of the eye at the point where the shoulder is attached to the threaded shank in some circumstances. Also, if the eyebolt threaded shank doesn't have a shoulder to deal with this side shear and instead has threads up to the shoulder, it could definitely fail much more readily. Using under-sized eyebolts and making up for the slop in the hole by using flat washers simply adds to the possibility of over-loading the eyebolt beyond it's designed use.
There are a host of specifically designed lifting devices that utilize a similar loop that can be swiveled and have a high-grade bolt(s) that can be used to attach them to whatever you are planning on lifting. You may wish to consider some of these choices for your use instead of the eyebolt. Otherwise you need to be willing to put yourself in a position of liability for accepting responsibility for using the eyebolts. I will try to include a link to an example of these lifting devices. Best regards, aevald

Attachment: hoist_rg.htm (32k)

By ctacker (****)

Date 11-14-2008 07:18 Edited 11-14-2008 07:23

Allen, The rigging class I referred to in another thread talked about using shouldered eyebolts(never use eyebolts that dont have shoulders on them), and using one on a 45deg angle is the equivalent of lifting 4 loads of the same weight at a straight vertical lift. thus a 1k load lifted at 45 deg you need a 4k rated shouldered eyebolt. I would agree a hoist ring would be a much better choice. another thing to remember is to use forged and not cast.
Also, the load rating factor for chains or wire rope at a 45 deg angle is 1.414 pounds for each pound lifted. so if your using 2 chains at a 45 deg angle off the horizontal plain and lifting 2000 lbs (1000 lbs per side) you would need 2 chains each rated for over 1414 lbs.
At a 30 deg. angle from the horiz. plane the load rating factor becomes 2.
and when you have 3 or 4 chains lifting an object, you always calculate using the limits for 2 chains.(they say only 2 chains are lifting and the 3rd and 4th are stabilizers)

I hope to get into this a little more as time allows.
Hope that helps

Carl

edit: try this as an example of lifting using the load rating factor, put a 1 lb weight at you toes and reach down and pick it up, now take the same weight a foot away from your toes, then again at 2 feet away.
see how it gets harder to lift as it gets further away.
the same thing happens when you spread your chains further apart.

By aevald

Date 11-14-2008 07:54

Hello Carl, I have no doubt that when used "properly", eyebolts can be used safely and not pose any unforeseen problems. If however, a load shifts unexpectedly for any reason, or if they are used for rolling or otherwise manipulating a load, I could see some real problems. Eyebolts such as these are an item that could easily be misused by someone unknowingly and that is the basis for my concerns for using them as lifting devices in the manner described. To me they kind of fall into the same category as improperly placed or welded picking eyes. Have seen numerous instances where picking eyes have been welded/stitch welded/tacked onto structures in order to roll them over or re-position them and once the item has been hoisted and the direction of load has shifted relative to the picking point there is a failure and the eye gives way. All of this is relative to education and understanding of some basic principles of both safety and rigging principles as you have already pointed out in your reply. My comments are mainly directed to individuals who might not be aware of some of these points as opposed to others who are already aware. For any who are following this thread or come upon it, at least they will have a bit more information about this situation and can make their own judgments on whether they would or wouldn't use this technique. Best regards, Allan

By DaveBoyer (*****)

Date 11-14-2008 05:13

I don't have any paperwork to prove it, but IF You oversize the eye bolt enough to deal with the off axis loading the Gr. 5 nut will be plenty strong enough. I doubt that an eye bolt is any stronger than a Gr. 5 bolt.

At the auto frame plant We used eye bolts loaded at 90 degrees to the bolt axis to lift heavy tooling, We used rather large eye bolts. For really heavy parts We had shop made lugs that loaded the ataching bolt in shear.

By rlitman (***)

Date 11-14-2008 18:20

Here's the way I see it (please remember that all numbers are for comparison purposes only):
Go to the hardware store (Ace by me has a good selection of these), and compare the ratings on the real forged eyebolts (say for comparison purposes 3000lbs for a 1/2" one), with the eyebolts that are just a bolt, bent into an eye shape, and not welded shut (say 300lbs for the same 1/2" one).
The difference is dramatic, BUT, the rating of the forged eye, is based on strictly pulling straight. The bent eye, may have its rating based on straight pull testing, but because of its shape (and the fact that the eye is open), it will fail when the eye bends open, and so its strength when loaded at 90 degrees is about the same as straight on (assuming its attachment is solid). I would trust the forged eye at 90 degrees, up to the point that the shank risks bending . . .
The difference is like being able to lift a car straight on, or a lawnmower otherwise.

Now, the OP referred to 45 degrees. Unfortunately, that's not halfway between straight on, and 90 degrees.
The force in shear, is the tension on the chain, times sin(angle). When that force exceeds the bending strength of the bolt, it will bend.
sin(45) is .707, so if the bending strength is 1/10th the tensile rating, you should not exceed 14% of the rating, not 25%.
sin(30) is .5, and .1/.5 = 20%.

By ctacker (****)

Date 11-14-2008 23:21

here's where my info comes from, watch out for buying shackles from a hardware store, they are cast and not forged

Attachment: SKMBT_50008111413570.pdf (43k)

By rlitman (***)

Date 11-15-2008 03:20

Nice chart. The numbers I was going through were just to show that for a -shoulderless- eyebolt, even a small deviation off vertical lifting severely reduces your capacity.
Yes, a shoulder helps enormously in preventing the shank from bending. I agree that its bad practice to pull these at more than 45 degrees from vertical, but that doesn't mean its impossible. Its just you would need something almost large enough to lift a house when vertical, to lift me, when pulled from the side.

Still, at 575lbs, and way heavier than my puny mill drill (which is the second largest thing I sometimes lift in my shop), I still only use 1 ton (and more) rated equipment, and load it the correct way, to lift my Miller AEAD-200le, and it still scares me when its more than an inch from the floor.

Funny thing, is none of this really speaks the the OP.
And, every time I buy forged eye-bolts, they come with matching nuts, so I don't even know how to answer that one. Hummm.

By ctacker (****)

Date 11-15-2008 04:44

>Funny thing, is none of this really speaks the the OP.
>And, every time I buy forged eye-bolts, they come with matching nuts, so I don't even know how to answer that one. Hummm.

I would agree that the OP got kind of derailed, I just took that rigging class a couple weeks ago, so its still fresh in mind, and since it was under the safety section, I wanted to throw out some of the safety issues involved in using eye bolts. Sholderless eyebolts are never to be used except straight vertical lifting.
The matching nuts are matched for a reason, your not supposed to swap them out! that should have been the answer for the OP. I'm not sure you can buy replacements without buying the whole thing, I have tried to find shackle pins and have yet to find them without replacing the shackle!

while were off the subject of the OP I had mentioned before that people need to be aware that buying shackles from a hardware store that most do not have a rating on them, and therefore are cast, and will break even when lifting under the rated load for the size shackle used. So I hope everyone looks at their shackles and if there is no load rating on them do not use them for lifting.

Keep it safe, Carl

By DaveBoyer (*****)

Date 11-15-2008 04:42

To elaborate on the eye bolts used at 90 degree loading: These were screwed into tapped holes in the edges of plates, castings or weldments. The eye bolts had a lockwasher and a heavy nut permanantly run down against the shoulder, and were screwed in with the nut as close as possible to the edge of the part without influencing the fair lead of the eye to the hook. We used 1", 1 1/4" & 1 1/2" eye bolts this way, and would on ocasion bend [and discard] them. In my years at that plant I never saw or heard of anyone breaking one.

The shop made lugs I mentioned used 1", 1 1/4" & 1 1/2" bolts, but the bolts were in shear with these and had much greater capacity, as there was no bending or prying forces.

By swnorris (****)

Date 11-19-2008 20:29

Eye bolts are designed for straight vertical pulls. Safe working loads drop off to 25% for 45° pulling angles.