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View Full Version : engine hoist swivel hook design?



metalmagpie
04-19-2012, 12:50 PM
There's a CL ad for a modified engine hoist with a clever design for a swivel hook, something I have long wanted for mine. See the pix:

http://www.tinyisland.com/images/temp/swivelHookBracket.jpg
http://www.tinyisland.com/images/temp/swivelHook.jpg

Everything looks easy to make for a guy who knows how to cut metal and weld it, except the actual swiveling mechanism. It looks like a flat rod with a hole, somehow attached to a thrust bearing.

How would *you* make this?

metalmagpie

Black_Moons
04-19-2012, 01:11 PM
Start with huge round (Billet!!)

Cut off two large chunks from each side to form the flat that the hook pins into.

Grind the flat to be narrower then the OD of the round, drill hole into U bracket that is larger then the flat but smaller then the OD

Alternatively, You could make the top chunk be a disk with a step machined into it, or similar, then put a pin through it that has a matching flange machined into it, and/or weld the two pieces together.

All depends how much you wanna turn versus weld and how much you trust your welds to support the weight in question. Personally I love the idea of 1 piece even if wasteful or at least a large machined step so the welds are not 'required' for high strength. Then again my welder is a little on the low current side so I don't like to weld such huge chunks of metal without deep gouges and many passes to fill it up.

camdigger
04-19-2012, 01:12 PM
My first impression would be to start with a large piece of stock and turn a top hat crossection. Mill flat and drill for crosspin to mount hook. Assemble clevis including thrust bearing and then mount to lifting arm.

Next would be to make the swivel pin on two pieces - a flat, extra thick washer and a pin with the flats milled to the width of the hook clevis....

coalsmok
04-19-2012, 05:42 PM
Forge out the rough shape of the swivel pin then machine to suit. Or just start with a bolt that is close the sizes required.

lakeside53
04-19-2012, 05:57 PM
A 1 inch (or whatever suits) grade 8 bolt with two flats milled for the hook, drilled for the clevis. Insert into suitable bearing (even an old radial) or thrust washers though U support. U support is just 3x5x3/8 tube with one side milled off.

oldtiffie
04-19-2012, 06:27 PM
Given that all "approved" swivel hooks and the like must be "rated" (with a prescribed safety factor) and some need to be load-tested, the implied risk is very high and a failure can be catastrophic.

I just buy approved or rated hooks.

http://www.acemlts.com.au/index.php?page=shop.browse&category_id=42&vmcchk=1&option=com_virtuemart&Itemid=34

http://www.google.com.au/#hl=en&rlz=1W1IRFC_enAU360&sclient=psy-ab&q=swivel+hooks+for+lifting&rlz=1W1IRFC_enAU360&oq=swivel+hook&aq=1&aqi=g4&aql=&gs_nf=1&gs_l=hp.1.1.0l4.0.0.1.23995.0.0.0.0.0.0.0.0..0.0.H 49HB0ZYqoU&pbx=1&bav=on.2,or.r_gc.r_pw.r_qf.,cf.osb&fp=bd47e94720a76d26&biw=1920&bih=785

uncle pete
04-19-2012, 06:35 PM
I've been doing far past what would be considered heavy lifts by the average HSM type person for over 40 years. If your not a mechanical engineer and a high pressure pipeline or atomic generating plant rated welder? Completely overkill is what your looking for. 100% Zero chance of failure for the weight is the bare minimum you should expect. I've seen a few failures for no apparent or logical reason with very well maintained and expensive lifting equipment. It's never pretty, Or cheap. Thankfully I didn't own the equipment and no one has ever got hurt or killed due to my refusal to allow anyone under a suspended load without safety blocking.

I've said it here before, But I'll repeate it again. I automaticly downrate standard off the shelf consumer grade offshore equipment like engine hoists, shackels, chains, slings etc by half. Those 2 ton Chinese rated engine hoists get downrated in my shop to a maximum of 1 ton and AFAIC that's even pushing it. Yes there's people who have lifted to their rating and maybe above it here. They can obviously do as they want. But they wouldn't be doing it with something I own dangling off the hook. If it weighs enough to use lifting equipment? Then that's not the place to cut corners. Sooner or later you will regret that. In any industrial setting I've worked in, Offshore and especialy Chinese built equipment won't be tollerated or used on any jobsite. It's judged as and is totall unreliable crap. And I do own a Chinese built engine hoist. Any welder today with more than 20 years experience will also mention how crappy the cheaper Chinese steel is today in comparison to the older North American steel. Actual costs for lifting equipment should be a secondary consideration.

Pete

cameron
04-19-2012, 10:45 PM
Good quality fittings for lifting generally have a rated working load of 1/5 or 1/6 of the ultimate strength of the fitting.

If you're building your own, there are three ways you can go.

1- Do it right, which means good design, including stress analysis of all parts, good workmanship, and assurance that material condition and strength are what you want them to be. And, while you're at it, proof test it before use.

2- Overbuild to the point there's no way in hell it's going to break.

3- If you don't really care if you drop the load, just eye ball it and hope you're right.

With procedure 1 or 2, you may be at least as safe as using cheap import equipment at its rated load.

metalmagpie
04-19-2012, 11:32 PM
OK, I get the safety thing. Don't beat it to death already. Personally I have always been a huge fan of overkill.

The original picture appeared to depict a swiveling post that was somehow integral to the thrust bearing, as opposed to just one sitting on top of a bearing. That's really what I wanted insight on, not how to weld a washer to a round rod, thanks.

metalmagpie

lakeside53
04-20-2012, 12:48 AM
How do you know it has a thrust bearing? Could just be a thick "washer" or turned head. If you want to bury a bearing inside, it's just a simple lathe operation.

Black Forest
04-20-2012, 01:51 AM
I've been doing far past what would be considered heavy lifts by the average HSM type person for over 40 years. If your not a mechanical engineer and a high pressure pipeline or atomic generating plant rated welder? Completely overkill is what your looking for. 100% Zero chance of failure for the weight is the bare minimum you should expect. I've seen a few failures for no apparent or logical reason with very well maintained and expensive lifting equipment. It's never pretty, Or cheap. Thankfully I didn't own the equipment and no one has ever got hurt or killed due to my refusal to allow anyone under a suspended load without safety blocking.

I've said it here before, But I'll repeate it again. I automaticly downrate standard off the shelf consumer grade offshore equipment like engine hoists, shackels, chains, slings etc by half. Those 2 ton Chinese rated engine hoists get downrated in my shop to a maximum of 1 ton and AFAIC that's even pushing it. Yes there's people who have lifted to their rating and maybe above it here. They can obviously do as they want. But they wouldn't be doing it with something I own dangling off the hook. If it weighs enough to use lifting equipment? Then that's not the place to cut corners. Sooner or later you will regret that. In any industrial setting I've worked in, Offshore and especialy Chinese built equipment won't be tollerated or used on any jobsite. It's judged as and is totall unreliable crap. And I do own a Chinese built engine hoist. Any welder today with more than 20 years experience will also mention how crappy the cheaper Chinese steel is today in comparison to the older North American steel. Actual costs for lifting equipment should be a secondary consideration.

Pete

Amen! OP, read this three times!