Leveling the lathe - not sure if I'm "doing it right"

[jrgilman95]

I have a Baileigh PL-1022VS (not the newer revision 2 they have under the same model #) that's seems virtually the same as Quinn's Precision Matthews lathe (at least the casting and a lot of parts are the same) from Blondihacks, so I've been following her video on leveling the lathe:

I got the bubble as close as I could using her method with two parallels, and now I'm cutting the test bar, I am getting pretty close by shimming the front left (the leg under the headstock closest to you when standing at the lathe), but a thought came into my head. How do I know if I should be shimming the front left leg or the back right leg? So I put my level on the cross slide and ran the carriage from left to right and the bubble stayed in largely the same spot in various positions along the bed: https://www.icloud.com/photos/#/icloudlinks/002DGEb_wo7ZsPbDt314lzJmA/

My first question: is putting the level on the cross-slide and moving across like I described above kosher? In my head it seems like it should be, since I'm just checking the relative position of the bubble at various positions along the Z axis?

If it is, this leads my to my second question, which is, if the bubble is the same across the length of the bed, wouldn't that indicate that the spindle/chuck are not perpendicular to the Z axis and need to be adjusted, instead of me continuing to shim the legs? If not, how do I know if I should shim the back right or front left leg? I assume the bubble would tell me since it would tell me if there is twist in the ways?

 

[cooper1203]

dont take this as gosple but i would of thought that if you were low on the headstock end when measuring with a spirit level from headstock to tail stock and low on the side nearest you when measuring across the ways then it will be the leg nearest you on the headstock end that is low. if you level across the ways then its both legs at the headstock end.

I belive the test bar comes in later to align the spindle and tail stock

 

[jrgilman95]

dont take this as gosple but i would of thought that if you were low on the headstock end when measuring with a spirit level from headstock to tail stock and low on the side nearest you when measuring across the ways then it will be the leg nearest you on the headstock end that is low. if you level across the ways then its both legs at the headstock end.

I belive the test bar comes in later to align the spindle and tail stock

So my understanding of the test bar is that by taking _extremely_ shallow passes (since your stick out is 6x your diameter) you can measure the taper your lathe is cutting. If the taper is larger at the headstock side it means your ways are either twisted in such a way that your front left foot is pushing your tool closer to the work piece near your headstock, or your back right foot is pushing it further from the work piece at the tail stock end. The end result is the same. The effect switches feet on both sides if the taper is larger at the tailstock side.

edit: maybe I misunderstood your reply though? Also I was under the impression that measuring level from the headstock to the tailstock only checks if your bed is curving up or down along the length. This would affect tool height when moving up and down the Z axis, but that's about it?

 

[cooper1203]

checking level along the length of the ways tells you which end is too high

 

[cooper1203]

if you dont have a machinist level but have an android smart phone there is a very good app called ruler pro

 

[Ulma Doctor]

Maybe you can find or build a King Way kit, if it’s gotta be gnats whiskers accurate.
A machinist level is the next best
But don’t chase your tail too much, unless you’re working sub-thousandths tolerances or doing high accuracy production work .

 

[jrgilman95]

Maybe you can find or build a King Way kit, if it’s gotta be gnats whiskers accurate.
A machinist level is the next best
But don’t chase your tail too much, unless you’re working sub-thousandths tolerances or doing high accuracy production work .

So I am using a machinist level (Starett 98-6) - I added an icloud link with a picture of the set-up. I was mostly curious about the theory and if my intuition was correct.

 

[cooper1203]

is that the one Quinn is using in her video? i think she mentions what the resolution of it is. did you calibrate it? it looks like from the first pic you leaning one way weather its on one end or both i cant tell from the pics

 

[jrgilman95]

is that the one Quinn is using in her video? i think she mentions what the resolution of it is. did you calibrate it? it looks like from the first pic you leaning one way weather its on one end or both i cant tell from the pics

Yeah exact one - yes it's calibrated.

The lean is simply because the table the lathe is on isn't level with the floor, but that shouldn't matter when you're just trying to compare one side of the lathe with another. I'll post a video in a second.

 

[verbotenwhisky]

I have a Baileigh PL-1022VS (not the newer revision 2 they have under the same model #) that's seems virtually the same as Quinn's Precision Matthews lathe (at least the casting and a lot of parts are the same) from Blondihacks, so I've been following her video on leveling the lathe:

I got the bubble as close as I could using her method with two parallels, and now I'm cutting the test bar, I am getting pretty close by shimming the front left (the leg under the headstock closest to you when standing at the lathe), but a thought came into my head. How do I know if I should be shimming the front left leg or the back right leg? So I put my level on the cross slide and ran the carriage from left to right and the bubble stayed in largely the same spot in various positions along the bed: https://www.icloud.com/photos/#/icloudlinks/002DGEb_wo7ZsPbDt314lzJmA/

My first question: is putting the level on the cross-slide and moving across like I described above kosher? In my head it seems like it should be, since I'm just checking the relative position of the bubble at various positions along the Z axis?

If it is, this leads my to my second question, which is, if the bubble is the same across the length of the bed, wouldn't that indicate that the spindle/chuck are not perpendicular to the Z axis and need to be adjusted, instead of me continuing to shim the legs? If not, how do I know if I should shim the back right or front left leg? I assume the bubble would tell me since it would tell me if there is twist in the ways?

Have you rotated and calibrated the level? Many do not like him but Adam Booth at ABOM79 has some good videos on setting up your level and leveling your lathe as well. There is also this video. Biggest thing is when leveling it should be level to itself not necessarily the world.