which lathe should I pick?

[spro]

Shop cranes can be a different subject and it was before. Trolley rail is good stuff and there are different types. Some is relatively light ( good for 200 lbs) depending on how it is mounted. If you have a few fixed points around the walls or from above, where a section of rail can be swung out and be supported, it is useful. Older, two post auto lift cradles were made that the extendable arms would swing out, outside the sides of the posts. If they aren't under a vehicle, they are hoists. I needed to move a small Atlas mill out of a cramped garage. By arms suspending rail with trolley, the mill was lifted, past the other machines and lowered to a dolly next to the vehicle. You can see it wasn't that easy and as one arm was swung the other was adjusted and there was a small winch but the traverse across 12' was otherwise impossible.

[BadDog]

If I hadn't found my "sky hook" cheap, I had planned on building one similar to the one linked from Lane. You're not pulling a motor, just lifting rotary tables, chucks, and bulky heavy tooling, unlikely for any of it to exceed 200 lbs by much (if ever). So having seen the sky hooks, I intended to make a simple rotary base with rigid upright and boom, then attach a simple cable drum ratchet such as used on small boat trailers. Add in an inverted question mark for "hooking" chucks (without eyes) and the lathe is covered. A bit of creative design on the base would also lend it to quickly attaching in other areas by t-nut, or clamped in a vise for use on a mill.

Regarding practicality, I can't imagine being without lifting devices of several sorts. I just used a folding shop crane (that has held a dressed 6BT with NV4500 and NP205!) to unload a Gannon that was way bigger than I thought when I committed to buying it (but I did, so I went through with it) and the tractor boom pole couldn't lift it. But my fall back if the crane had failed is an A-frame gantry with chain-fall. They all get used with surprising regularity, and I've considered adding an invalid lift for more convenient use in the shop when the crane doesn't fit and the sky hook can't practically be made to work

[liveaboard]

I have a 1 ton electric chain hoist on a swinging gantry; but it's in the garage and most of my work isn't! I got it cheap at auction but the foundation and bracing was extra.
The difficulty is having enough headroom in the workshop. If you have space then you can set some sort of beams against the walls and a cross beam on rollers, then have a chainfall or other lifting device that will cover your workspace.
There are always things to move around, and the human spine just isn't engineered for that sort of thing.
My lathe is only 9" so I can still set the chucks manually, but if it was any bigger [or I get any weaker] I'd definitely take the time to rig up something.

[spro]

I think you mean 9" chucks! IIRC, your lathe is a heavy one.

[SteveHGraham]

Shop cranes can be a different subject and it was before. Trolley rail is good stuff and there are different types. Some is relatively light ( good for 200 lbs) depending on how it is mounted. If you have a few fixed points around the walls or from above, where a section of rail can be swung out and be supported, it is useful.

This is the option that has always appealed to me. I don't need a crane to switch chucks, and there is no way I'm going to clutter my garage further with a bulky hoist that's always in the way, but it would be nice to have something overhead and out of the way, for lifting and moving larger things.

I have a chain hoist, and I would love to have it rigged to a rail instead of fixed in one place. It's very useful as it is, but you can't lift anything that isn't already directly under it.

[BadDog]

I saw some posts (PM?) from a guy who rigged (from what I recall) 2 parallel beams along the walls low enough to put a trolley on top with a cross beam hugging the floor (upside down to normal, but left max head room for mills and such). So the cross beam had rolling dolly along it's length, and the whole cross rail traveled end to end in the garage. Could pretty much lift anything from anywhere and go anywhere. As I recall the beam just cleared the mill motors, and the only place he couldn't go was with the dolly/chain-fall right over the tall machines. The span was great enough that max load wasn't huge, but well within the range of even 15" rotary tables and such.

I've got my big fabrication/setup table build from the table of a horizontal boring mill. Must weight close to 1000 lbs. It's on casters so that it's mobile, you just don't want to push much across the narrow way, wouldn't want it to tip, but as long as you're mindful of the expansion joints and such it moves around the shop readily enough. Anyway, I have an adapter for the sky crane to mount on the table t-slots (or the mill, but that's another discussion). That allows me to put things on the table, move it, and place them as needed. I've planned on a permanent set of outriggers to prevent tipping, but the base is built of channel iron so it's easy to just clamp on outriggers as needed when lifting too much and concerned about tipping.

[liveaboard]

I think you mean 9" chucks! IIRC, your lathe is a heavy one.

Yes! I meant chuck size. Except I made an error, as I work in metric. My largest chuck is 200mm, slightly under 8"

[spro]

Steve G. I replied but deleted what liveaboard and BadDog had already said. The places we worked had a superstructure of channel steel and/or I beams above the floor working height. The area above probably held more weight than below, in many cases. I could've driven a tractor into the freight elevator and parked it in some office, removed the ceiling panels, and hoisted an engine right there. Of course, I would have been rightfully shot dead before getting that far. But the superstructure remains a concept. Not all beams are wooden, for some times a section can rotate out and be supported by a jack post for use with a trolley or hoist. Also; some ways allow an extension of one type into another, so that it can be fixed at variable length at points along a wall.

[liveaboard]

The gantry hoist I have swings from the center of one wall, and describes a half circle with about a 10' radius.
That leaves a lot of space uncovered [unless you have a circular workshop!]
And a lot of structure had to be put in to hold it up.
If you have a rectangular space and can get away with it, a setup that covers the whole area would be much better, and not even harder to install.
A half ton or even a whole ton isn't difficult to lift, depending on the wall to wall span of course.
I was considering building a new workshop, and it would have had the steel beams built into the walls; but I can't get planning permission for anything where I live.

[Glenn Brooks]

1) tail stock wear - bottom of the tailstock worn down causing tailstock alignment to drop below centerline. Results in out of round parts and off center drilling, etc.

While your comment of off center is correct, the out-of-round is not, although it can be.

Here's how and why.

We are normally admonished to face a piece before drilling a center hole. If you don't, and the piece isn't running in dead straight alignment, assuming you've drilled a 60° center, not one of the oval type, as the piece rotates about the drilled center hole, the center tracks the periphery of the drilled center hole, which is not running true (it oscillates left and right as it rotates). That results in strange behavior of the part, including cutting a less than true circle, as well as altering, albeit ever so slightly, the squareness of the cut.

There are center drills on the market that create a slight spot face around the center hole. They, too, eliminate that problem.

Those considerations aside, a low tailstock, while VERY aggravating, doesn't generally create any problems with roundness. It does make the use of reamers difficult, however, as it does the use of small center drills. For that reason, one is well served to ALWAYS wipe the tailstock ways and re-oil before moving the tailstock. That goes a long ways towards reducing unnecessary wear of the base of the tailstock, as well as the ways, which have a way of accumulating an undesirable collection of dust, which becomes lapping compound when the tailstock is moved.

Harold

Thanks, Harold. Poor choice of words on my part. In retrospect, Out of Round is probably way to vague... What I meant to suggest was lathes with low tailstocks, may create an eccentric shape vertically. Also if the wear is uneven both front to back and side toside, it may cause the horizontal axis of the tailstock to both plunge downwards and be off center - resulting in complications when trying to locate and/or drill the center of the work piece, bore thru and thru, or cut internal threads parellel with the OD of the (round) workpiece etc.. Hope I am expressing my idea correctly...


Glenn

[BadDog]

Lathes generate shapes of revolution, so tailstock misalignment would generate a conical section, taper direction depending on offset. And if a tool is mounted, like a center drill, it still describes a circle on the part and tries to act more as a boring bar, which is what breaks the tips on smaller center drills. The only way to generate an eccentric with the tailstock is by fitting to an offset located center socket.

[Harold_V]

What I meant to suggest was lathes with low tailstocks, may create an eccentric shape vertically.

Depends on the setup. If one does work from a chuck and uses a center, unless the material runs dead true at the center, what you propose is true. What happens is that any eccentricity at the center hole manifests itself in a compromised arc, due to the tailstock flexing and the quill oscillating to some degree. While the end result is generally a round part, it won't be concentric with the hole in said part.

By contrast, if the piece is held between centers, none of that will be true, as centers permit dead alignment, even though they may not be in alignment themselves. That manifests itself as taper only.

Also if the wear is uneven both front to back and side toside, it may cause the horizontal axis of the tailstock to both plunge downwards and be off center - resulting in complications when trying to locate and/or drill the center of the work piece, bore thru and thru, or cut internal threads parellel with the OD of the (round) workpiece etc.. Hope I am expressing my idea correctly...

The tailstock doesn't enter in to the equation when doing through work, as there is no way for the tailstock to be applied, so operations such as internal threading are not of concern in that regard. However, if a work piece is held in a chuck, machined externally with a center, then the center removed and work done internally, there is a very real possibility that the internal work won't be concentric with the external work, for the reasons I mentioned above.

The misalignment of the tailstock raises issues when one attempts to use small diameter center drills, which are too rigid to displace, so the tip is often broken off. The alignment issue is also VERY troublesome when one uses reamers, as they demand concentricity in order for them to perform their desired function. When there is misalignment, they tend to create bell-mouthed holes, and often gentle tapers as the reamer is slowly forced to center. All in all, a very poor situation, which is why floating reamer heads are often employed, allowing the reamer to seek center.

While it is common practice for long work, held in a chuck, to be supported by a tailstock center (I do it, too), it is not good shop practice, for the reason I suggested. Only when working between centers is the material free to move as it is prone to do, and still yield a straight part. I will confess, there are numerous occasions where the resulting work is acceptable, however, as stresses in round material are often reasonably balanced, so there is little movement when the material is machined.

For a clear understanding of the condition I have described, one is well served to have spent time on a cylindrical grinder, where parts are pretty much routinely held between centers. All manner of issues are apparent.

It is safe to say that one should not use a center in conjunction with chuck work, assuming that concentricity is of importance. If it is, the problems inherent with such a setup can be largely controlled by roughing the entire work piece, leaving sufficient material for finish cuts, as the piece most likely will not be straight, nor will the roughed cuts be concentric with one another. That can be accomplished by advancing the material in steps, so cuts are kept close to the chuck. When the piece is fully roughed, and in final position in the machine, only then should the center hole be drilled. At this point, the bulk of movement of the material has taken place, and the center will be on location in regards to the status of the material as it relates to the spindle centerline.

Bottom line---if one must machine long parts, held in a chuck, the center hole should be drilled last, so it isn't used to force the part to center. Does that make sense?

Harold