Getting twist of of lathe with only 2 mounting points

Keep in mind, leveling isn't a one time deal. Over time you have to adjust it. So shims can be a bit of a pain. With adjustment bolts it's much easier, which means I'm more likely to do it.
 
Terry, that's a great addition to the lathe. I'm curious how much twist you found. From what I gather, eliminating twist is more important than being level and it may take some back and forth to eliminate twist and have the ways level in two directions. I think that's where your setup will really simplify the process.
As RJ mentioned above, the lower, right motor mount nut is inaccessible (on the G0752) with the lathe sitting on the chip tray. By elevating the lathe slightly, I wonder if it's now possible to access that nut. That would be another bonus.
 
The 602 has an adjustable headstock. The mounting holes in the headstock are slightly oversized to allow the adjustment as are the grooves for the V ways. There are two setscrews (412 in the parts diagram) on the backside of the headstock which work against the mounting studs to facilitate movement of the headstock in a controlled fashion.

Caution should be used in making this adjustment as it also affects the ability to cut a flat face. I would check that before determining that an adjustment was required. This can easily be done by mounting the faceplate and installing a 1/2 x 1" bolt and nut in one of the faceplate slots. Position the bolt to the outside of the slot for maximum sensitivity. I domed the head of the bolt and polished it to make easier for a test indicator to ride on the head and for more reproducible measurements.

To use, I set up a test indicator on the cross slide positioned so that it can sweep ther face of the bolt when the faceplate is positioned with the bolt nearest the front and horizontal to the spindle axis. Rock the faceplate to hind the point of greatest deflection of the test indicator. Move the cross slide slightly to find the point of greatest deflection. Zero the indicator. Rotate the faceplate 180º and repeat the process. If the reading is zero, the cross slide ways are perpendicular to the spindle axis and a facing operation will yield a flat face. If the deflection is greater at the rear, a concave face will be cut and if is less a convex face will be cut. The only adjustment possible on the 602 for this is rotation of the headstock. Because of that, I would not recommend using this adjustment to correct for turning a taper. I made that mistake early on correcting a taper turning issue and ended up cutting a convex face.
Some machinists advocate cutting a slightly concave face to prevent a part from rocking when placed on end on a flat surface. I do not. I will check my cross slide perpendicularity first and then deal with any taper turning ossues as being caused by bed twist.
 
John281 said:
Terry, that's a great addition to the lathe. I'm curious how much twist you found. From what I gather, eliminating twist is more important than being level and it may take some back and forth to eliminate twist and have the ways level in two directions. I think that's where your setup will really simplify the process.
As RJ mentioned above, the lower, right motor mount nut is inaccessible (on the G0752) with the lathe sitting on the chip tray. By elevating the lathe slightly, I wonder if it's now possible to access that nut. That would be another bonus.
Click to expand...

Thanks John. There was minimal twist. I did not measure it before. In my situation the back of the bench was slightly lower so all the adjustment was done with the rear levelers. I'm not sure about access to that bolt but I'll check it when I get home. I definitely like the additional space under the bed one way or the other. Should make cleaning much easier.

I posted a thread with the leveling plate information...

https://www.hobby-machinist.com/threads/lathe-leveling-parallelism-using-shop-made-levelers.72014/
 
John281 said:
Terry, that's a great addition to the lathe. I'm curious how much twist you found. From what I gather, eliminating twist is more important than being level and it may take some back and forth to eliminate twist and have the ways level in two directions. I think that's where your setup will really simplify the process.
As RJ mentioned above, the lower, right motor mount nut is inaccessible (on the G0752) with the lathe sitting on the chip tray. By elevating the lathe slightly, I wonder if it's now possible to access that nut. That would be another bonus.
Click to expand...
Yes, you should be able to access the motor mounting bolts. Because of the fins on the motor housing, using a socket wrench with even a 1/4" drive isn't possible.

A box or open end wrench can access from the side but there is limited range of motion. At least 40º is needed for a 12 pt. wrench. The near side side are no problem but the inside nuts would require removal of the splash guard to access them.

By raising the lathe by 3/4 or 7/8", a wobble extension or a flexible drive could be used. Even then, the clearance is such that a very shallow socket would be needed. It is also likely that the motor cooling fins may have to be bent or cut away for access.
 
John281 said:
Terry, that's a great addition to the lathe. I'm curious how much twist you found. From what I gather, eliminating twist is more important than being level and it may take some back and forth to eliminate twist and have the ways level in two directions. I think that's where your setup will really simplify the process.
As RJ mentioned above, the lower, right motor mount nut is inaccessible (on the G0752) with the lathe sitting on the chip tray. By elevating the lathe slightly, I wonder if it's now possible to access that nut. That would be another bonus.
Click to expand...
I'm seeing that too. I take out some twist, need to work on leveling and vice versa. When I though it would be difficult to take out twist...HA!, more the contrary. Every time I touch about anything, the twist changes. It feels like I am adjusting, calibrating and leveling more than actually making anything. If it wasn't for the test barbell, I wouldn't be making any chips!
 
John281 said:
Terry, that's a great addition to the lathe. I'm curious how much twist you found. From what I gather, eliminating twist is more important than being level and it may take some back and forth to eliminate twist and have the ways level in two directions. I think that's where your setup will really simplify the process.
As RJ mentioned above, the lower, right motor mount nut is inaccessible (on the G0752) with the lathe sitting on the chip tray. By elevating the lathe slightly, I wonder if it's now possible to access that nut. That would be another bonus.
Click to expand...

The nut is easily accessible now. Hope I don't need to access it any time soon though. :grin:
 
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