How NOT to Lift a Lathe

[DeSelle]

This is pure laziness. Will it ruin the lathe? Probably not. But its bad practice and this is how people get hurt. People get away with things all the time until they don’t.

 

[Doozer]

If the lifting methods falls within engineering parameters
and care is taken not to let the situation get outside
those parameters, then it is fine.
Just like toolpost grinding on a lathe.
Dust control is a primary parameter.
If you control that parameter, (keep the
dust contained and out of/off of the lathe)
then it is OK.
But I get it. You can do something a different
way and it is easier to stay within a set of
parameters or maybe then the parameters don't
matter because the method of engagement is
totally different.
Kinda like you don't have to be lucky if you
are good. Well maybe.

---Doozer

 

[JST]

One of the lathes here weighs maybe 500 lb, but the nose ball bearing has max rating of 8000 lb, in the bearing data. Somehow I doubt there would be an issue there. I'd still not do it, just "because"...it seems like a not-good idea. But that bearing is not in danger.

Others have plain bronze bearings, and I'd definitely not do it with them.

 

[ratbldr427]

Bronze bearings have a heck of a lot more area to spread the load over than rolling element bearings! So why not?

 

[JST]

Actually they do not....

The journal is smaller than the bore, to allow oil room, so the contact is actually only over a theoretical line, but actually a larger area based on the hardness and elasticity of the material. Bronze is not that hard, and may be deformed.

The ball bearing has a defined load limit, which is ridiculously in excess of the machine weight. I don't have numbers for the bronze bearing, and am unwilling to go with my own calculations.

 

[ClappedOutBport]

Actually they do not....

The journal is smaller than the bore, to allow oil room, so the contact is actually only over a theoretical line, but actually a larger area based on the hardness and elasticity of the material. Bronze is not that hard, and may be deformed.

The ball bearing has a defined load limit, which is ridiculously in excess of the machine weight. I don't have numbers for the bronze bearing, and am unwilling to go with my own calculations.

Ball bearings contact in a line too. As do tapered rollers. Bronze bearings have huge contact patches. I'd sleep like a baby with those bearing stresses.

P.S.

How many of you have seen a lathe with chuck rash? Or how about badchuck rash? In those crashes, what do you think the peak/instantaneous bearing force is? More than the lightweight China lathe I'd bet. But most of them are still rolling.

 

[thermite]

I lifted my Sidney by the spindle with a bar sticking through. With 3 big bearings... uh yeah, don't think that they are going to Brinnel any sitting static with one load application. Besides that, they were already fucked.

Married a "used Lady" like that onct. Got sore expensive.

Tried again with wiser moves next go. 31 great years and counting.

Go figure machine tools can work out much the same.

 

[JST]

Ball bearings contact in a line too. As do tapered rollers. Bronze bearings have huge contact patches. I'd sleep like a baby with those bearing stresses.

...............

The ball and roller are hardened, and rated for the usage. And the elastic deformation of the surfaces makes the ball and roller actually have larger contact patches than a "line".

I don't like the idea of the journal potentially "scrubbing around" a bit on the bronze during the lift. And bronze is not as elastic as hardened bearing steel.

I'd not worry at all about 500 lb on an 8k rated ball bearing. At 2k, I'd want to take a good look at the static rating.

No need to do it when there is a nice big lathe bed to clamp a lifting point to. IIRC that is the factory plan for Colchester.