I need to set up a chain fall to unload a lathe from a pickup truck. The lathe weighs about 600 pounds. The roof in my garage is built with common trusses made of 2X4s, 24″ on center with 4/12 pitch spanning 20′. I’d like to bridge 4 of the trusses with a 2X4 and attach the chain fall to the 2X4 about 1/3 of the distance from the end of the trusses shown by the red rectangle in the attached drawing.
Will it carry the weight?
Replies
You do know that you aren't supposed to do that. Those trusses are not designed to hang concentrated loads from. However, I weigh over 200# and have never caved a truss in by standing on the bottom chord.
I wouldn't use a 2x4 if you try this. That could easily break with a load of 600# hanging from it.
I don't doubt that a standard garage truss, in good condition, can carry an additional 600 pounds of weight. But the bottom chord isn't intended to carry much load, and I'd be (slightly) concerned that the joint might separate on you. (Also concerned a little about the ability of a 2x4 to carry 600# on the flat.)
The 2x4 isn't, if attached flat against the bottom of the trusses, going to distribute much force beyond the center one. Better to figure out how to apply the load safely to a single truss, perhaps using your 2x4 to reenforce the joints somehow.
I was going to put the load centered between two of the trusses in the belief that it would at least get distributed across each truss to either side. It makes sense that the load wouldn't get distributed beyond those two trusses. That makes 300# per truss. I'm starting to get scared.
Why not rent an automotive engine removing cherry picker, or a material lift? One or the other should get you what you need.If you're not familiar with Old Woodworking Machines website, go there (http://www.owwm.org) and search on "rigging" for ideas.I wouldn't test the strength of your trusses. You could be fine; or you could be SO, um, [term that relates to a threaded fastener].
Edited 10/17/2009 8:22 pm ET by Houghton123
If you use a 4x4 to span 4 trusses, you would be a lot better off. You would really be a lot better off if you forgot the whole idea and found another way to unload the lathe!
I way 300 lbs and am not scared. Just make sure that the trusses are in good shape, and for goodness sake, don't use a 2x4 on the flat!!!
years ago I just hired a tow truck to do the same thing.
Trusses ain't designed for live loads of that spectrum.
Eric.
What I have done in the past is to use a 4x4 spanning four trusses. Put two kickers in cut to fit tight between truss and floor. Back up truck as close as you can to the kickers with tailgate removed.
Raise lathe and pull truck ahead. Lower lathe.
Mike
Quickstep,
Done similar by using 4x6 spanning trusses and then posting(2x4 T's) under the trusses so they didn't carry any load except the weight of the 4x6. Screw every thing together so it can't shift.
KK
If you placed a 4x4 across 4 trusses and connected a length of chain in a swag from midway between trusses 1 & 2 to midway between trusses 3 & 4, then hang your hoist tackle from the middle of that chain swag, you would be placing 150lb on each truss.
That's less than if you walked on one.
Call your local rental yard and have a forklift dropped at your door. i have done it many times for my machinery. safer and cheaper. Last time i did it, I had my ducks in a row and the company dropped the lift, I unloaded the machine and reload the lift as the driver waited. Took about 15 minutes and I paid $135 for rental and in/out fees. A day use is usually around $250, some places charge more.
Or, rent a Budget truck with a liftgate. I just moved a 16' trucklet of equiptment and because the distance was <10 miles round trip, I paid $50.00(plus I have a pallet jack)
Ditto to what Junkman said. I have done the same a number of times. DanT
Of course, $135 would buy a lot of beer. 600 pounds is something six hefty guys could handle easily (if you don't open the beer until after).
As I stood before the gates I realized that I never want to be as certain about anything as were the people who built this place. --Rabbi Sheila Peltz, on her visit to Auschwitz
what does one little oops cost?
Unless the replacement cost is cheap, then it just aint work it. I concider it cheap insurance.
My 37"wide belt sander weighed 800-1000lbs. to replace it was $8k
Taking the time, setting up bracing, and a chain winch isn't going to be cheap. Not including a few cases of good beer.
After all the back problems that I have gone trough, I have learned to work smart. Plus, the wife hates it when I moan after doing "stupid"
No matter how you do it, an "oops" is always possible. Depending on the object, often having several reasonably strong men to handle it is the safest approach.
As I stood before the gates I realized that I never want to be as certain about anything as were the people who built this place. --Rabbi Sheila Peltz, on her visit to Auschwitz
(This comes to mind because I'm remembering back to my college days when I watched a couple of "bump and grind" (Buildings and Grounds) guys struggle to move a piece of test equipment (probably weighing 600-800 pounds) into one of the engineering buildings while about ten profs stood around giving advice. They finally sent for a fork lift, but if the guys standing around had each put a hand on the thing (it was long and narrow, so easy for a bunch of people to lift) they could have easily moved it.)
As I stood before the gates I realized that I never want to be as certain about anything as were the people who built this place. --Rabbi Sheila Peltz, on her visit to Auschwitz
Like some of the others have said - It's too much for one truss.
Use a beam of some sort 8' long. Lay it across at least 4 trusses, and hang your chain inbetween 2 trusses. That should spread it out pretty well.
Don't try it if the trusses are home made ones. And if ya hear a lot of cracking and popping give it up and try something else.
Looked to me like if the connector plates were good for 500# each, and the roof had no snow, he could do it - while listening for 'pops' <G>
Was going to look up nailplate shear strength once, could not find a good on-line set of tables - you know where any are online??
e.g. for homemade trusses, 'hydraulic' pressing in the nailplates between a driveway and the stabilizer on a backhoe.
Shear strength on the plates isn't generally a limiting factor. Most often it's just the square inches of plate area.Never seen anyone try to use a backhoe stabilizer to press truss plates. Seems like a pretty slow method, either dragging the truss around or moving the backhoe. I think it takes 400 PSI to press them in, so you couldn't do a really big plate that way.
When Humpty fell, I wonder if they tried duct tape?
Shear strength on the plates isn't generally a limiting factor. Most often it's just the square inches of plate area.
I'd guess the plates would be engineeried for those 2 factors to be equal? Or do the designers factor in a bigger safety margin for shear strength/pullout so the steel yeild often could fail first?
They have to balance the tooth holding and shear values, I guess. And they have to work with several different species of lumber. On most residential trusses the tooth holding is gonna be the bigger factor. Shear comes in to play on larger trusses or very unusual ones.
The government is like a baby's alimentary canal, with a happy appetite at one end and no responsibility at the other. [Ronald Reagan]
several different species of lumber
Good point, Out here it is near 100% west coast hemlock and DFir. I do get some SYP on pallets from Texas and Georgia and S.C.
Still have never used nail plates for any DIY trusses myself, always end up using glued on plywood gussets or bolt thru connections.
In defense of OP, he did show his point of attach at a joint, which is where the calculated 450# min shear came in. I'd not hesitate to load a similar truss to 600# at the joint for a short period of time.
Son's attached garage has a similar truss to OP truss, 30 ft span, but 16" oc. Put a 1/2 ply floor over the tension 2x4, doubled the strength of the 16 ft garage door opening by bolting a 3/16 by 6" steel blate to the bottom face of the 6x12 glulam, attached 1x6 to bottom chord of each truss on far side of drywall with deck screws(partly to make sure drywall screws dont pull thru the drywall). 7 years now and no sag or deflections, I did post for them a BIG chart on permissible loading - e.g NO big boxes of books in center span, etc. and leave the aisle down the center clear! <G>
600# at one joint would be WAY too much IMHO. It might work if the plate was positioned perfectly and there were no flaws in the wood. But since we can't see the guys' trusses I'm not willing to make that bet. If he got a truss where the plate was an inch too low the joint itself might fail, even if the rest of the truss held.
This is a nice place to visit, but I really wouldn't want to live here
600# at one joint would be WAY too much IMHO.
ah, that must be why all the 3/8" bolts on my shed trusses are bent <G>
Before you start, could you take and post here pictures of "before lift" and "after lift?" Oh yea, be sure to attach that 2x4 to the bottom cord with sheet rock screws, the long ones, "toe nailed" into the sides of the cross piece.
Thanks...
Several good simple solutions have been proposed so far. If you feel more comfortable go ahead and rent the forklift/engine hoist or whatever.
If I were in your shoes and didn't want to break a truss I would do the temporary posts already mentioned to hold up the truss and if you really wanted it to be secure just clamp or screw a 4 by 8 (or similar) to the truss in question and put the posts underneath it.
That should take the load off the truss but be sufficiently stable.
Karl
We got something similar to this:http://www.northerntool.com/webapp/wcs/stores/servlet/product_6970_200305491_200305491http://www.tvwsolar.com
We'll have a kid
Or maybe we'll rent one
He's got to be straight
We don't want a bent one
He'll drink his baby brew
From a big brass cup
Someday he may be president
If things loosen up
Snort,
those imported hydraulic hoists can be surprisingly capable. I have one similar to the one you linked to that has a small hand winch as well as the hydraulic ram I can bolt to the bed of my f350.I managed to lift an empty 500 gallon propane tank onto the truck with it. I didn't have any thing else available so I approached it with a lot of determination to make it work but it didn't seem to pose much of a challenge. I looked up the weight of a random 500 gal tank online and it was listed as 1100 lbs so I think the lathe the original poster is dealing with should be an easy task.The nice thing about an engine hoist is that he can probably roll it under the truck bed to grab the lathe from its center of balance and just pull the truck out from underneath the lathe.Karl
We've moved a lot of heavy stuff with that hoist, an 800lb concrete slab... a 12" table saw from the back of a truck... but no one ever felt brave enough to get underneath the weight<G>http://www.tvwsolar.com
We'll have a kid
Or maybe we'll rent one
He's got to be straight
We don't want a bent one
He'll drink his baby brew
From a big brass cup
Someday he may be president
If things loosen up
Another vote for an engine hoist/cherry picker - you can usually rent them for a nominal fee. The only problem may be that since the lathe is in a pickup, the hoist may not have a high enough lift range to pick it out of the bed.
I helped a buddy setup a hoist to lift car engines in his garage and we tossed an 8 foot fence post in the truss webs and wrapped a chain around the middle and fed it thru a hole in the drywall cieling. Still working fine 10 years later and can't see and deflection in use.Rik
Simple solution to that: Just hang the lift from the roof trusses.
As I stood before the gates I realized that I never want to be as certain about anything as were the people who built this place. --Rabbi Sheila Peltz, on her visit to Auschwitz
snork....
Life is Good
Looks like an engine hoist is the way to go. By the time I bought enough lumber to rig it up right, I can rent the hoist. Only $30/day. Might save a lot of pain literally and figuratively
Whenever I'm at the scrapyard I have to check out what they have for sale. Walked in one day last year to find a pile 4 feet high and 6 wide of chain hoists. All different sizes and $25.00 each. Just about killed me. When I moved last time I sold or junked a semi-load of 'stuff' so I have learned to be strong but it's still hard.
What about a ramp?
I use that Egyptian method too
Welcome to the Taunton University of Knowledge FHB Campus at Breaktime. where ... Excellence is its own reward!
This is a simple rigging problem. Forget hanging it from your trusses; the right way is much simpler.
Set up a tripod made of 4x4s or 3" steel pipe. Chain the legs to each other at ground level so they can't spread. Back the truck under it. Hook the chain fall to the apex of the tripod, and hoist the lathe off the deck of the truck. Drive out from under it, and lower away onto your bedplate.
Dinosaur
How now, Mighty Sauron, that thou art not brought
low by this? For thine evil pales before that which
foolish men call Justice....
That is exactly what I was going to suggest earlier today, but got an email, then forgot to reply.Probably just as easy, though is to thread the aformentioned 4x4 through the rafters. Then set two 4x4 posts, vertically, from the floor up... And bolt those to the 4x4 that is through the rafters.Take maybe 15-20 minutes to set up, 15-20 minutes to dismantle when done...It's all fun and games, until someone puts an eye out..You are always welcome at Quittintime
Make the tripod with 4x4s and one 5/8" x 16" carriage bolt. Leave the bolt a bit slack so the outer legs can spread. 12-footers will be more than long enough to get the width and height required to back a truck under it.
Cheap 'swing-set' chain is strong enough for the anti-spread preventers. Wrap it around the base and run a #14x1½" screw with a washer through a link into each leg.
Loop a 2" web nylon tow strap over the apex; loop it enough times to bring the eyes at the ends of the strap together underneath. Hang the chainfall from them.
Dinosaur
How now, Mighty Sauron, that thou art not broughtlow by this? For thine evil pales before that whichfoolish men call Justice....
That is exactly what I did, to remove an engine from a truk, here.I let the ground itself be the anti-spread mechanism, but other than that, I did it exactly the same...It's all fun and games, until someone puts an eye out..You are always welcome at Quittintime
My dad used a similar trick for pulling engines, but he never would have dreamed of the extravagance of store-bought 4x4's and carriage bolts. He used logs cut on his own property and a chunk of rebar in place of the carriage bolt.
Yep, that'll work fine.
Tripods and shear-legs are standard rigger's tools. In the days of 'iron men and wooden ships'--pre-power machinery, in other words--such devices were commonly used to hoist and install the masts on ships.
If a ship's rigging or spars were damaged in a storm or battle, the normal procedure was to jury-rig something that would enable the ship to limp to the nearest island with trees on it. It was taken for granted that, without shipyard facilities, with nothing but the hand tools carried on board, the ship's crew would in a relatively short time replace and re-rig any damaged spars.
Assuming nothing left standing of the original spars (a radical assumption, but...) the new mast would be floated out and laid alongside. It would be hoisted on board using doubled slings made fast on deck at one end, passed under the mast, and led to the capstan. Heaving in would roll the timber right up the side of the ship. No crane or derrick required.
Those huge, tall masts were raised into position by hauling a pair of sheer legs shorter than the mast vertical with the capstan. The sheer legs were assembled, and laid on the deck. The feet were stopped on pads and made off with preventers so they could not slide. A line to the apex was led to the capstan, and was heaved in as a gang started the apex upwards. As the angle got steeper, the force required to lift it decreased logarithmically.
As the the sheer legs rose, a line from the apex made off to the mast at about 2/3 of its height would start pulling up, instead of sideways. Eventually the mast would be vertical, it's weight supported by the sheer legs, and could be lowered through the decks to the mast step on the keel. Obviously, as the whole mess got close to vertical, guys and preventers were rigged to keep it from toppling over.
Once one lower mast was in place, it could be used to hoist up the top masts and yards other upper spars.
Dinosaur
How now, Mighty Sauron, that thou art not broughtlow by this? For thine evil pales before that whichfoolish men call Justice....
Which is exactly the method I suggested several weeks ago when someone wanted to lift a long wall section. Make an A frame. fix the legs at the bottom. Tie off one top side to your truck and the other top side to the top of the wall. Viola wall comes up with no manual effort.
Of course, the trick among others in your boat scenario is not dropping the thing through the keel.
the trick among others in your boat scenario is not dropping the thing through the keel.
Yeah, that'll get you 50 of the bosun's best.
All these traditional procedures are preserved in Darcy Lever's classic 1808 bible of seamanship and rigging, A Young Officer's Sheet Anchor, available in an excellent cloth binding from Lee Valley's Algrove Publishing Classic Reprints division. Best $30 bucks you could spend on yourself for an early Christmas present....
Dinosaur
How now, Mighty Sauron, that thou art not broughtlow by this? For thine evil pales before that whichfoolish men call Justice....
Did you already try this once? http://forums.taunton.com/tp-breaktime/messages?msg=125745.1
Rent a scaffold and hang hoist from a 6x6. That would be fairly inexpensive. A forklift or engine hoist is great but could be more expensive.
mike
I've thought about this a lot, and I have two answers.
The first is, by spreading the load across several trusses, you can almost certainly get away with it. Whether you should is the question. Yat brins us to the thinking that leads to my next answer:
Trusses are designed to hold up the roof. That bottom piece is there to keep the angle between the top pieces from opening. You could replace that bittom piece with a length of wire rope, and the roof would remain solid; that's because the piece is in 'tension,' rather than 'compression.'
So, what you really want to do is to hang / attach / support that beam holding the hoist from the top two parts of the truss - not the bottom chord.
Just a minor point to argue with ya - The bottom chord is in tension MOST of the time. But wind can cause uplift situations in which the forces are reversed. Also - Trusses are made for loads spread out over a wide area. He's talking about hanging a load on one joint. In that case the strength g the plate at that joint becomes the controlling factor. Tension in the bottom chord would be fairly small.
John Kruk: "I'm not an athlete. I'm a professional baseball player."
You may be right. The last time I did truss calcs was in engineering school, back in the 70's, and I wouldn't know where to begin today.
So what did you finally decide to do?
And was it successful?
Haven't you seen the broken truss thread?
As I stood before the gates I realized that I never want to be as certain about anything as were the people who built this place. --Rabbi Sheila Peltz, on her visit to Auschwitz
Just screw a bicycle hook into the bottom chord... works like a charm.
I ended up renting an engine hoist to remove the lathe fromt he truck. The estimate of 600 pounds may have been on the light side. The hoist made relatively easy work of it, but you could tell that thing was heeeeeeaaaaavy. It's pouring driving rain here now. It would suck if I didn't have a garage roof. The hoist cost $30 to rent - cheap insurance for the safety factor. Thanks for the advice.
On a different note, this would be a good time to use it as an excuse to buy a used backhoe or loader<G>
Float it down.
Make a box a little wider that the lathe, put banding around the corners to keep it together. The top edge should match the truck edge.
Put a PVC tube on the bottom with small holes drilled regularly, made in such a way that it circles around the bottom of the box like a gas burner. Put an air fitting on the end sticking out of the box with a valve.
Fill the box with sand. Cover it with 1/2" plywood.
Bring the lath home and slide it on top of the box. Cover the lath with plastic.
more later
Tu stultus es
Rebuilding my home in Cypress, CA
Also a CRX fanatic!
Look, just send me to my drawer. This whole talking-to-you thing is like double punishment.