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I want to lift the body off my 66 VW (not the whole car). Since I already have a 450 lb rated hoist, I decided to take an advantage of it and use it for lifting. This comes handy specially when try to put the body back on the frame. Question I have if my design can handle the weight? I am only planning to suspend the body for a few mins, until I move the frame out and place the dolly under it to lower it down. With that said, I have I have two 2”x6”- 5 feet long going across the front and rear windows opening. (inside I have some extra woods / padding so it not resting on the doors). On top I have a 5 feet long 2”x8” with a 1/2" eye in the center of it. The bottom woods are fastened to the top wood with 3/8” threaded rods and also all the bolts are 3/8” head.

The weight of the body is 200 LB, but for safety, let’s assume is 300 LB. can the woods handle the lift? My main concern is the top wood which is lifting 300 LB (~ 150 on each side). can 150 LB on each side bend the 2”x8” enough to break it? All these woods were purchased from Home Depots. Not sure what kind of woods they are but used for constructions. enter image description here enter image description here enter image description here enter image description here

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  • You can increase the strength of the existing structure by rotating the planks 90° which then distributes the force over the greater dimension of the lumber. – fred_dot_u Feb 11 '20 at 16:11
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    I'm a little more concerned about that ceiling you're suspending it from... – Jamie M Feb 11 '20 at 16:39
  • I can't believe you would build a thing like that without turning the wood edgewise, especially because in several places (e.g. the 2x4s) it costs you nothing. Do you just not know how much stronger that makes it? I would endorse it if the 2x4s and top beam were edgewise; as is, no. – Harper - Reinstate Monica Feb 11 '20 at 17:08
  • where do those circled threaded rods go? are they holding the track up? is ir sumething like a beam that goes over the bottom part of 4 or more trusses? – Jasen Feb 12 '20 at 3:46
  • They are fastened to a 4x4 which is sitting on top of the two 2x4 joists – borna Feb 12 '20 at 4:19
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This will most likely work if the body is as light as you say, but that seems like an optimistic estimate. When you start to lift, the board should tell you if it's going to be ok.

By the book, this isn't strictly "safe", but I don't have a problem with self-engineered solutions. The one thing you have to remember is to treat the lifted object as if it could fall at any moment. Never put yourself or one of your limbs under the body and always predict how it will fall if it does and stay out of that path.

What you have created will work, but it is also dangerous in that it has not been tested or properly planned/designed. It could damage the car, and it could damage you, so treat it like a pending failure, and be happy when everything does work out.

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  • I second this. The lumber is the LEAST of his concerns. It looks fine. The wench... I do not like how thin the cable is. I would rather use a rope/pulley . – DMoore Feb 11 '20 at 16:29
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Pay very close attention to the attic structure and how this hoist is attached up there. A minimal attic truss with only 2x4 cross members on the lower joists is not up for this.

I'm not happy with it grabbing only 2 joists. (tell me you didn't just use drywall anchors? Drywall has 0 strength). I'd be happier to see it grabbing 4 joists.

I'm very concerned with the possibility of the attic trusses running parallel with your mounting beam so you are only attaching to one of them. If so, you'll want to go up in the attic and install some cross members to spread the load to 5 trusses at least. Use those 2x8 and fit them vertically on edge, with Simpson ties.

Also, from the way your design gratuitously lays all the wood on its side, I'm guessing that you did not get the memo that wood is much, much stronger lain on edge. Ask on engineering.se why that is, but you'll notice all the working beams in your attic are edgewise.

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  • Good point about picking up more than one joist. I think two is ok if the car is as light as described and the load is up there briefly, but I agree that one is not enough. – JPhi1618 Feb 11 '20 at 18:22
  • @JPhi1618 Well, the worst that could happen would be pretty expensive and destructive, so I suppose it's OP's call. I for one would prefer a rig where I wasn't forced to hurry, because hurrying introduces its own matrix of risks. – Harper - Reinstate Monica Feb 11 '20 at 18:32
  • As far the installation of hoist, I drilled 2 holes on a 4x4 and pass the threaded rods through it into the ceiling and fastened it to the metal bracket which the hoist is sitting on it. now the 4x4 is sitting on top of the two 2x4 joists in the attic. I am thinking this is not different from me standing on top of the joist in the attic, but I could be wrong. Also I am not planning to keep the body up for more than 2 or 3 mins. Once is up, I'll pull the chaises out and bring the body down to a dolly. – borna Feb 11 '20 at 19:10
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The wood should be fine. Like the others have said, there are other concerns. Is the ceiling attach strong enough? The safety margin on the hoist is marginal. I would like 5X.

Calculation for the 2 x 8 on top. The deflection is not acceptable for building construction, but OK for what you are doing.

enter image description here

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  • Why have a safety factor of “5x” when you footnote one your calculations says 10x ? Also, the safety factor from “ultimate stress design” to “working stress design” is generally 1.8 for most building (static) members. The OP says it will be supporting the car shell for just a few minutes. Why not use “impact” loading. – Lee Sam Feb 11 '20 at 17:24
  • @LeeSam What does "just a few minutes" have to do with anything? For instance a heavy semi-truck is on a bridge for seconds so does that mean the bridge can be built lighter? – Harper - Reinstate Monica Feb 11 '20 at 17:25
  • @Harper-ReinstateMonica Yes, there are different stresses used for “short-term” loading and “long-term” loading. If snow only lasts for a week, the design stresses in lumber can be increased by as much as 100%...thus allowing the designer to use smaller size lumber. (This does not apply to steel or concrete.) – Lee Sam Feb 11 '20 at 17:34
  • My opinions, which come to the same conclusion as some of the others. 10X for construction (the bottom footnotes are generic), this is not long-term construction. 5X for the hoist, OP does not have this much margin, others are concerned as well. – Mattman944 Feb 11 '20 at 18:33
  • @Mattman944 Your calculations are for the member on “edge” and the pictures show the members on side. – Lee Sam Feb 11 '20 at 18:49
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wood table pic attached

if u are going to use 2x8 in the lifting orientation per your pic, then you're doing it perp. to the grain and you are not taking advantage of it's strength... which is ok you can just stack 2x8's two, three, or four thick to meet your strength needs. Not ideal obviously.

the smarter thing to do would be to use a lifting strap to allow orientation of the 2x8 so you can lift parallel to the grain (with the 8" side of the 2x8 being vertical)

i didn't modify the pic's for 2x8, it is for 2x4.

rather than using one 2x8 you could easily use two or more 2x4 passing through the interior to lift the body.

be mindful of ripping your hoist out of the ceiling. Strength of using [multiple] lag bolts into ceiling joists is completely independent of the attached wood compress/shear tables.

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  • use basic 2x4 stud which is doug-fir, typically 1000 lb shear strength used properly parallel to grain; use 4 total: 2 through each window with a plywood topper to keep it orientated and prevent the 2" side of the 2x4 denting in to the body- spread the load out so it's not a lifting point on the body. Then only worry about strength of hoist mounted to ceiling. – ron Feb 11 '20 at 16:54
  • You understand the table is just the stress values for various species. It CANNOT be used to determine loads without knowing span of member, etc. – Lee Sam Feb 11 '20 at 17:08
  • he's not using a 16 foot length, and not doing anything complicated. an 8' long enough to pass through the body using a nylon sling on each end, using the max load as a reference. I though that would be reasonable and obvious more most people to interpret. – ron Feb 11 '20 at 18:19
  • there, no more incorrect load tables – ron Feb 11 '20 at 18:20
  • As far the installation of hoist, I drilled 2 holes on a 4x4 and pass the threaded rods through it into the ceiling and fastened it to the metal bracket which the hoist is sitting on it. now the 4x4 is sitting on top of the two 2x4 joists in the attic. I am thinking this is not different from me standing on top of the joist in the attic, but I could be wrong. Also I am not planning to keep the body up for more than 2 or 3 mins. Once is up, I'll pull the chaises out and bring the body down to a dolly. – borna Feb 11 '20 at 18:43

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