# Optimal length of lag screws

I have a wooden cart on casters on which I will have a generator. Its weight is 1,400 lbs, and the weight of the entire stucture would be 1,600 lbs. This cart may one day be winched into a trailer on ramps.
To the front of the cart, I want to attach a lifting eye. It is a big lifting eye with the threaded stem removed, and welded to a 1/4" plate, which would be attached to the cart by means of four 5/16" lag screws.
My question is, what is the optimal length of these lag screws. The wood is regular soft wood. I assume that beyond some length, the extra grip given by extra length is meaningless.
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I'd use bolts, not lags.
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I have worked with lag screws extensively and I do not feel confident that lag screws will hold consistently any heavy load if the stress is being applied vertically. Horizontally (to the lag screw) perhaps, but not vertically.
If the lag screws are stressed sideways, I would want at least 3 1/2" to 4" minimum.
I would suggest some kind of threaded BIG bolts, another plate on the other side from the eye plate, and extra nuts.
I have built platforms that needed to be winched onto a trailer or truck before. What I did was to jrill a big hole and run a bolt throough it. I cut out a section near the middle of the bolt. I then threaded the bolt through a big iron ring. This was sufficent for any kind of hook or other means of attaching the cart to the cable.
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wrote:

Here's a lag screw load calculator: http://www.awc.org/calculators/connections/ccstyle.asp ?
R
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RicodJour wrote:

Actually, it also for bolts, wood screws, and nails...

Good link to have handy - thank you!
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Morris Dovey
DeSoto Solar
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EXCELLENT link! that one's going into the favorites.
jc
wrote:

Here's a lag screw load calculator: http://www.awc.org/calculators/connections/ccstyle.asp ?
R
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In article <ac323131-1442-4f7e-9869-
says...

Thanks indeed! That's a great tool to have around.
I'm planning something akin to what the OP is doing. I have an unfinished room above my garage with access only to the second floor of the house (it's where they generally put the "bonus room"). My plan is to use if as my shop (convert it to the bonus room if I move).
I'm trying to think of a way to get tools and materials up there, so was considering a hoist (what's the difference between a "hoist" and "winch"?) with an access door down to the garage. I'd have to lift a table saw (~600lbs.), hence the interest in this load calculator.
-- Keith
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krw wrote: ...

Hoists are for lifting, winches are for pulling.
As well as the connection, need to be sure you're attaching it to something that can hold the load.
A FWW a couple years ago had a shop in upstairs over garage w/ the same idea. It, of course, was designed dedicated so he designed for and installed a full length trolley beam, but a simple block and tackle was sufficient for lifting even larger qear. (IIRC, he had an old 20+" jointer which would have been roughly twice your weight...
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What's the difference? A winch rated for 1000lbs. has to pull with 1000lbs. force. A hoist has to pull the same force. Obviously I'm missing something basic here.

The "attaching it to" is easy. A few 2x12s can easily support a 1000lbs, once the interface problem is solved. ;-) The floor has to support the same load.

I thought of using something simpler since moving the tools is a one-time (maybe two ;) thing. I figured that once I solved the difficult problem of the tools, materials would be a piece of cake. I also need to get a pile of plywood (flooring) and sheetrock up there. Carrying any of this stuff through the house won't impress SWMBO. The fallback position will be to keep the big tools in the garage and move partially finished stuff upstairs. This doesn't sound like a lot of fun though.
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Keith

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krw wrote:

Winches for pulling don't have the safety locks for overhead lifts hoists do...
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Some winches don't even have a brake on them, so when you turn it off the line is allowed to go slack.
It might be like the distinction between a rabbet and a dado. At their most basic, they're a groove cut in wood. They have distinct properties, however, that make one more useful than the other in certain situations.
Puckdropper
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Ok, that makes some sense, at least. Hoists automatically have safety locks? What sort of locks?
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Keith

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krw wrote: ...

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Ok. ;-) Is there anything, written in stone, what these locks have to be? Is there a way of determining what they are for a given hoist? Specs? Standards?
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Keith

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krw wrote:

I'm certain there are many Standards and, of course, in the US, OSHA rules. What any are, specifically, by number I don't know; not my field. I don't think there are requirements on the braking mechanisms themselves, per se, only that they perform the required specified function in a failsafe mode.
Look at the two links I posted earlier that point at a typical winch and overhead hoist to get an idea of the difference in equipment (and note relative costs).
The general definition, however, holds--winches are for pulling and hoists are for raising.
While there are lots of folks who ignore such rules and many winches do have brakes and locks that are designed to prevent backsliding, they aren't intended for overhead lifting and such usage is risky at best.
It's a lesson learned in the electric utility business where lifting is common, often complex and serious. It's no less serious for an individual w/ a 50-lb load above them--it'll kill just as readily.
For a home shop kind of thing you mentioned, unless you have budget, I'd go w/ the manual chain hoist myself rather than the power option.
A good block and tackle works, but isn't nearly as risk-free or convenient.
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I would think there would be pointers in the literature ("meets xyz789") but I see nothing.

I did, but the two aren't comparable for many reasons. One is a commercial/industrial unit and the other is a homeowner's unit. Such makes for bad comparisons.

I understood that. The difference obviously isn't the force, so I asked specifically *what* the difference was. You've done a decent job of explaining the difference. I only want a bit more information ao I know what to look for (or forget the whole thing).

I wouldn't be lifting anything over my head, though wouldn't much like to see a \$2000 saw break my garage floor either. ;-)

Sounds like a RPITA to lift 10'-12'. Most I've seen don't have that sort of lift.

Sounds more risky than a winch.
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Keith

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krw wrote: ...

I wasn't shopping for you, I simply showed two that are roughly the same pulling power-rated mostly so you could see the characteristic difference between the design of a winch vis a vis a hoist.
It's up to you to select what level of performance you're going to be satisfied with, I'm merely attempting to ensure you do understand the essential difference to avoid, hopefully, an accident down the road.

I'd stick w/ reputable vendor/manufacturer and check out the manuals. I believe it's required for all to be compliant in the US to be legal, but it's an area of sufficient gravity (pun intended) that I, personally, would avoid the cheapest of Chinese knock-offs a la Harbor Freight, etc. They may be fine, but I'm not trusting my life to one, thank you very much.
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Actually, they're not that bad and have the facility to simply stop at any point. I think...flip, flip, flip--ah, yes...looking at the catalogue, Northern has up to 24' versions that I'd trust for \$150 or less.

Not really if the winch doesn't failsafe on loss of power, for example. I don't recommend it as the first choice if the intent is a 1000-lb TS, but I don't have any real problems w/ them, either, if one is familiar w/ their operation. Having grown up on the farm we used the farm hay rake routinely and handled easily that much routinely but practice makes for easier and safer usage. It was 1-inch rope and does have reverse ratchets that work like dynamic braking on elevators if it starts to lower too rapidly and also has locking device. It was originally designed for use w/ horse/mule team, of course, although had switched to tractor power by the time I was large enough to be involved. Manually, one uses a snubbing post similar to a stationary bulldogging post (I'm sure that's a reference you're totally familiar with... :) ).
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One could (as I've already done) do the same with two hoists. Your comparison was unhelpful (though the rest of your posts have been quite helpful - thanks).

I've got the idea, but it still sounds dangerous. Many of these old farm devices were.
I still haven't completely thought through this idea. You've given me a lot to think about and safety is certainly one of my concerns. Thanks again.
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Keith

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krw wrote:
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Well, so be it...
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Your out of context quotation makes me look unappreciative of your efforts. That certainly isn't the case. This one comparison was all I was unhelpful.
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Keith

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