Turning a load on pipe rollers is done by angling the leading rollers in the direction you want to turn the load.
To get the lathe up onto the truck, my suggestion is to use skid timbers under the bed of the lathe. Skid timbers are typically rough-cut 6 x 6's for a lathe the size of this one. The ends of the skid timbers are cut on about a 45 degree angle, making "sled runner ends". Skid timbers work well if you have an un-even bottom surface or have a machine tool on legs. They also work well at providing a "lead" to get things started up onto a tilt bed truck. The other advantage to skid timbers is they help with rollers, having that "sled runner end", the rollers find their way under the load.
Going up onto the truck bed, it becomes a question of what the rated capacity of the truck winch and wire rope are vs the weight of the lathe and condition of the bed. The classic problems in basic HS physics dealt with coefficient of friction, inclined planes, and force needed to break loose and then slide a load. Obviously, if the bed is diamond plate vs smooth steel plate on the truck, this makes a world of difference. The words of the physics teachers and later, college professors, talking about "Mu times N" are ringing in my head, altho it is some 42 years since I graduated engineering school. Mu = coefficient of friction (varies with materials and lubrication, and usually, you take the static friction coefficient). N = load, or force applied normal (perpendicular) to the sliding surface. The lathe may weigh a few tons, but on an inclined plane, you do the trig to get the force applied "normal" to the inclined plane.
I've been around quite a bit of heavy rigging in my career. One thing I learned early on is to never take a chance on a load "getting away". Some of the rigging I was involved with included sliding generator stators weighing 320 tons off railroad cars and moving them overland on greased sliding beams, using cable falls and winches. Other rigging included various jacking schemes. Hillman rollers, or "skates" that looks like "tank tracks" are OK if the surface you use them on is smooth, flat, and hard. We used Hillmans, but we always put down a runway of steel plate or channel. Hillmans can chock and lock on a small piece of rock or a stray welding rod stub and then the load starts slewing.
My own 'druthers for DIY rigging is the old Egyptian methods, including pipe rollers, and simply using greased steel plates and comealongs to slide/turn a load in a tight location. My other recommendation is to make sure you have means of controlling the load. I've seen loads on rollers seemingly want to take off on their own if there is a slight depression in the surface the rollers are on. Something like wood planks on bare ground is the sort of situation where the planks may have some spring to them or the ground compresses a little, and the load suddenly wants to take off downhill. I was taught to always provide a "holdback" to let out on as the load is pulled ahead, whether on rollers or slide plates.
Another tool which can work wonders is a 6 foot pinch bar. With a load on rollers and a pinch bar, you can steer the load once it start moving. Other tools that come in handy are:
steel flanging or setup wedges- used to get under the base of some machinery to lift it slightly off the floor when there seems like no other way and you do not have a hoist or crane handy.
sledge hammer (aka "beater") to drive the wedges
steel shims
sleever bar (aka lining bar). This is about a 30" long steel bar, forged to a pointed drift on one end, rolling pry on the other. Indispensible when moving machinery or doing any kind of erecting work.
chainsaw- great for cutting dunnage and skid timbers
Slings, load chains, shackles
comealongs. I use ratchet chain type comealongs, rather than find myself playing with load on a wire-rope "fence puller" type comealong and having to screw around with the pawls.
Wood shims
Another wild caper concerned the moving of some railroad passenger coaches a few years back. We hired a crazy house mover to do the job, cut rate price. We provided the manpower and a lot of the other equipment. He provided an engine driven hydraulic power unit and lifting rams, as well as needle beams and road dollies. We jacked up the railroad cars and slid needle beams under them, and placed pieces of dunnage as shimming and then steel sliding plates under the frames of each car. We set the needle beams on wood crib piles, and slicked the tops of the beams with Ivory soap. We then used a winch on the back of the house mover's old Mack to slide the cars sideways, one end at a time, and then jacked them and let them down on the road dollies. The Ivory Soap made a good lubricant, and since we had an audience of unknown people, we did not want to be seen slopping on grease. It did not take much to slide the railroad cars, and we did not have to use any blocks (pulley blocks) to multiply the effort of the truck winch.
As you get into the job, things will sort of solve themselves for you if you keep your wits about you. One thing is to measure your route, where the lathe has to be moved to get it to the truck, and from the truck into your shop. Check widths of doorways, check floor loading (if you are on something other than a heavy concrete slab floor poured at grade). Look for points where you might attach a comealong to pull the lathe along. It may mean putting some drilled-in anchors in the concrete floor and attaching temporary lugs (pieces of steel plate with an "ear" welded to them with a hole for a shackle). Never get your fingers or other body parts under the load unless it is supported solidly on blocking or steel shims.
Never get between the load and a wall or other tight spot when it is being moved. Never step over a chain or wire rope or sling under tension. Check to be sure turning the lathe has adequate space. If need be, make a scale drawing and make a cutout of the lathe from a file folder or similar. Play with the move of the lathe by sliding the paper cutout of the lathe on your scale drawing to be sure it can make the turns. We used to do this on heavy rigging jobs where we had a lot of turbine and generator parts crowding in a powerhouse, or had a load to move past existing plant equipment. Sounds silly, and I know a lot of the younger people will sit there and say: "Why do that, you can use "sketch up" (or some similar computer program). Well and good if you can, but I am old school, and the people I worked with were old school. Get to moving several hundred tons of powerplant equipment like a generator stator or a hydro turbine generator rotor, and you want to be real sure of where you are going and what you are doing. I tend to be what is called a "concrete learner", so playing with paper cutouts and hand drawn sketches and running numbers on any kind of rigging is what I do.
There is an old saying on this kind of work: "It's real easy to go from a hero to a zero", and a rigging job can go wrong in the blink of an eye. Egyptian methods, and keeping the center of gravity low, and taking it slow and making "worst case" assumptions are cheap insurance.
Joe Michaels