How not to lift a lathe !!!

Peter

I'm glad to see that you have upheld the "evenly balanced" nature of this forum and only quoted an "average" machine (VBG). These things also seem to be badly affected by their position on earth and of course by the awful weather this side of the pond. Must be too wet for them (VVBG) over here. Sorry Peter couldn't resist.

I also can't imagine that it is good practice and in my ill informed state would worry about the difference between the static loading of the bearings with 3/4 ton on a line contact and the normal dynamic loads that the spindle bearings were actually designed for. While I'm happy to accept the 7.5 ton load on a 1/4" bolt and have often risked my life in those cars that Chapman created to prove it. We are not looking at total failure as the only cause of likely damage here. All we need is some deformation of the bearing track or roller surface to create enough of a problem to reduce the life or performance of the machine. A couple of other things would concern me, the 3/4 ton load will in fact be greater to overcome the inertia needed to lift the machine and I've worked with many crane operators who are quite capable of breaking things by snatching fairly small loads. All these worries without getting as far as the potential bending loads on the spindle which again will react differently than when loaded statically rather than dynamically.

Merely voicing my ill educated concerns as I'm certainly not qualified to provide real answers, I'll leave that to the PhD brigade. I suppose I would ask why take the risk (however small) of causing damage by lifting this way when there is no risk to the machine whatsoever if you use the manufacturers recommended solution. Is that slide rules I can hear clacking, oh no silly me it's calculators these days.

Best regards

Keith

these

statically

qualified

suppose

Interestingly it now comes to mind that I once bought a Colchester Student that seemed in very good nick, but when turned by hand the spindle bearings made an awful noise. On dismantling I found that two of the rollers in the Gamet bearing had collapsed and a hole had been punched by them through the outer race (The rollers are hollow having cone shaped recesses meeting in the centre). I wonder if it was lifted in a jerk (and maybe by a jerk!) by the chuck ! Fortunately I found a s/h bearing set as the quoted new and discounted price was several hundred pounds.

AWEM

If by "me to" you mean that I too have figured out that this is probably a bad idea, then yes.

The spindle & its bearings are probably strong enough to handle the static load without permanent deflection, but I'm not sure that I would want to risk it given that the accuracy of the spindle is fairly important to the general well being of the lathe. However, even if the static loads aren't too much for it, would it handle the shock load if there is any slack on the cable drum/pulleys/etc. that suddenly released, allowing the whole shooting match to free fall before the slack gets taken up again? Not at all clear.

Much less clear whether the tailstock spindle is up to the job of handling either the static load or any possible shock loads without damage. Would you be willing to take the chance?

No doubt each of the straps is good for the whole of the load if one of them (or its attachment at the top) should fail; however, lose the left hand strap and the chances are that the tailstock handwheel would slip out of its strap and you have the lathe landing headstock first on the deck. Not nice.

Regards,

My manual said to use holes that were *way* below the C of G. I tried it, it was too risky.

Nick

hmmmm !!! pic taken from my garden

all the best.mark

Sorry, I was just being more explicit :-)

Note my other comment about lifting an ML7

Mark Rand RTFM

survived ok ... no damage that was about three years ago ....

heat of the moment sort of thing ....yup did notice that ...when it was up in the air ....but it was down on the floor 10 seconds later.

all the best.mark

yep .........my manual tells you so ...pic below

On or around Mon, 23 Apr 2007 08:22:40 +1200, Tom enlightened us thusly:

the spindle and the tailstock are not designed for lifting the machine on.

as has been said elsewhere, earlier colchies have a special hole for fitting a lifting eye.

LOL. You'll have to excuse me Tony, as I find your "doubts & suppositions", less than technologically compelling. I mean to say, do any of the following belong in a "technical" dissertation: "probably", "I'm not sure", "risk it", "would it?", "not at all clear", "Much less clear", "take the chance?' "chances are", "not nice"

Tom

Tom -

I don't notice you providing any "compelling" arguments that it is an OK thing to do - just smartass comments from the sidelines.

Regards, Tony

Excuse me? Your remarks weren't smartass? As for compelling arguments from me? Remember? I asked the question, now you want me to supply the answer? LOL.

Tom

Absolutely. Its clear from, your question & subsequent posts that you believe its a perfectly reasonable way to lift a lathe. So, convince me.

Regards, Tony

The method shown is good only if the properly sized slings are used.

As shown the support provided would be similarly stable as it would be sitting on the floor of the shop, not bolted down. Pretty stable, that is.

Cheers Trevor Jones

Have a *close* look at the picture! Only two slings used. Look at the hook! Now who guarantees that the slings don't start slipping in the hook and the nice new lathe simply tilts to one side?

Anyhow, they want to sell lathes or spares! :-))

Nick

Gravity, balance, and weight.

By the time the weight of the machine is applied to the slings, they will not roll around the pins. The tension on the slings pulls the individual runs into the shape of a pyramid, also stable. It looks to me to be accepted rigging practice, from what I have seen done, and what I have read in some books.

Bigger and heavier than that have been hoisted the same way safely for many years, and will be done so into the future. Ther were an awful lot of palletized cargos lifted out of transport in the same way, in the days before sea cans, too.

Just because the CG of the entire load is above where it is attached to the lift slings, does not make the load unstable. The CG of the load is well below the lift point of the slings.

Cheers Trevor Jones

Again, as soon as the slings slip in the hook, you hopefully know where to run. The width of the base is small compared to the distance lash point CG. This means that the CG has only to be lifted a bit and then the dynamics start.

Well, hm, ja. I'm impressed. :-)

Nick

Absolutely? LOL. You can make such a positive statement based on my posts yet are unable to make a positive argument against the manner in which that lathe was hoisted? I think you need to lay off assumptions, Tony.

Tom