Chain hoist DONE

I have not done that much, but I am feeling proud. The chain hoist is now suspended beneath a 6x6"x8' wooden beam, lying on 5 joists, on a steel beam held by two 1/2" threaded rods that are under very equal tension. I feel that it can handle a ton, which is more than I need. Even if I ever buy something like a military surplus Onan DJC generator, it would be way under a ton.

The wooden beam has a slight arch-like bend in it, about 1 cm, which was reduced by tensioning to about 0.5 cm. The benefits of it are going to be better weight distribution and some minimal amount of cushioning in case the load drops a few cm for some reason.

Thanks to all for correctly pointing out dangerousness of my previous setup, and making helpful suggestions.

How much does a bridgeport mill weigh? ;-) our military base has a few for sale. :) Since I may soon have 3 phase gensets, I could try to buy one mill, maybe for resale.

i
Reply to
Ignoramus7414
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Photos:

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The joists are 2x7" , spaced 16" apart, and are supported by a load bearing wall 5 feet away, and another wall about 15 feet away.

i
Reply to
Ignoramus7414

On 6 Nov 2004 02:33:30 GMT, Ignoramus7414 vaguely proposed a theory ......and in reply I say!:

remove ns from my header address to reply via email

Drills mercilessly in...:-<

I would watch the spot where you have the shackle pin going through the T piece. I am not sure, and nor do I have any idea how to calculate the strength of the, but it looks like the spot.

If you ever expect a ton, would you stand 14-15 people at the spot the chain hoist is hanging, up in the attic? Still think about those pillars for heavy stuff.

***************************************************** Have you noticed that people always run from what they _need_ toward what they want?????
Reply to
Old Nick

Reply to
RoyJ

Looks good, just don't put a ton on that thing..

Reply to
Michael Shaffer

snip------

Barely under one ton. The series II machines are much higher, though.

Harold

Reply to
Harold & Susan Vordos

They are actually "Cincinnati size 2 model OO", whatever that means.

Looks just like the milling machines I saw in Russia, big, cute and heavy.

That said, I don't think that I'd want one, it is too big.

i
Reply to
Ignoramus22442

The CNC version of the Series I Bridgeport (BOSS-3 through BOSS-6 version) is something like 3300 pounds, IIRC -- so over 1-1/2 tons. (There are lots of heavy transformers in that machine, including a big three-phase one which provides the power for the three stepper motors, and three mag amps (saturable reactors) to adjust the supply voltage to the steppers on a per-axis basis.

Enjoy, DoN.

Reply to
DoN. Nichols

snip----

Not the same thing, perhaps not even close. ??? Curious why you asked about a Bridgeport then. Can I conclude that you call any drop spindle mill (assuming the Cincinnati in question is a drop spindle mill) a Bridgeport because of its design?

The Bridgeport is exceptional (you can read that "cheap") in that regard. Many drop spindle mills of similar size weigh far more than they do.

No, I'm not down on Bridgeport. I own one, and have purchased two of them, both new, in my lifetime. They were an exceptional bargain for a shop, especially a small scale one, but they have never been known for their high quality, nor their robust construction. Gorton produced a far better machine, but not as flexible for making setups.

Only you know what type of work you intend to do. There are times when my Bridgeport is too small, other times when I'd love to have a smaller machine, especially with higher spindle speeds (in spite of the 4,200 RPM I have). If the price is right and you have space, it could be a good investment, depending on your objective.

Harold

Reply to
Harold & Susan Vordos

Nick I would be concerned about the drilling of the two vertical holes close together in the beam. The bolt holes should have come up alongside the beam with the connecting strap over the wood beam.

JRW

Reply to
J.R. Williams

Um, is what you are suggesting not what I did? I dud just that. Bolt holes alongside the beam, diagonally related to the pin attachment, and metal connecting strap over the wood beam.

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i

Reply to
Ignoramus22442

No, they are through the beam. The whole setup is kind of scary. I wouldn't use it for more than about 300 pounds. That attic ceiling was not meant to support additional weight.

Reply to
ATP

Common sense suggests that since people put stuff in the attic, it was made to support that stuff. There are 2x7" joists spaced 16 inch apart, supported by a wall 5 and 15 feet away.

i
Reply to
Ignoramus17472

You may want to get your sense-o-meter calibrated. The joists are in tension, keeping the roof load from pushing the walls apart. The joists(2"x7"??) already are undersize for a 20 foot span.

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The rule of thumb for overhead lifting is the working load should be less than 20% of the load causing failure. My suggestion would be to go to the library and check out Harry Parker's "Simplified Design of Structural Steel" and "Simplifed Design of Structural Timber", and go through the numbers until you have a better idea of what "common sense" is. The fellows here are trying to keep you and the anatomy you have become attached to together. But, as Jack Sobon the timber framer used to say, do what you want, you will anyway.

Kevin Gallimore

Reply to
axolotl

I've never heard of 2x7 joists. 2x8 joists on a 20 foot span are meant to hold the sheetrock up, and maybe a few boxes of old papers and junk, not a ton suspended from a chain hoist!

Reply to
ATP

Maybe they are 2x8". In any case, I take your criticism seriously and will not attempt to hoist a ton. Practically speaking, I foresee a need to soon lift about 400, 600 and 500 lbs items.

i
Reply to
Ignoramus17472

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