Level or Not

[Vladymere]

All,

What darkzero says about the method of calibrating the level is true.

It is not necessary to have the level calibrated when using it to level a piece of equipment. Just make sure, if you have not calibrated the level, that you maintain the same orientation of the level when you move it from one end oh the lathe to the other end of the lathe or from one side of the lathe to the other side of the lathe.

A lathe need not be level to work well. Think of a lathe on a ship. What is needed when leveling is to insure the level orientation remains the same and adjust so the bubble is in the same location in each position, I.E.- a half a bubble off level at the headstock and a half of bubble of level at the tailstock, with the level orientation maintained, means the bed is leveled along the length, the twist in the bed is removed.

After leveling use the "two collar method" to tweak the bed for best performance.

Vlad

 

[kickback1122]

I have a 12" atlas/craftsman that I'm going to level on its base/cabinet. Do I need a machinist level to check across the ways, I know it would be ideal, or is that overkill and a good quality and accurate level all that's needed if ensure that the bubble is "dead nut" center?

 

[Jim F]

I have a 12" atlas/craftsman that I'm going to level on its base/cabinet. Do I need a machinist level to check across the ways, I know it would be ideal, or is that overkill and a good quality and accurate level all that's needed if ensure that the bubble is "dead nut" center?

You do not need a level.
you need to remove twist.
you can lay a lathe on its side, as long as the bed has no twist, it will work fine.

 

[mac1911]

Completely new to this myself.

Few things I learned.
Before checking and spending many hours chasing your tail check to see how true your lathe is cutting.
My lathe ways are short and the bed is solid. When my friends dad checked it out he said twist will be minimal on a short stout lathe like mine.
Took his advice. Get the lathe clean , adjusted and repair anything worn or broken.
My lathe is level by carpenters standards. Lol.
Plan on going a step ahead and get my lathe aligned best as possible

Just compare your ways readings from end to end an few points in between. As mentioned keep the same orientation

The saddle ? Can you influence the saddle by the lock or gib adjustment?

 

[kickback1122]

Completely new to this myself.

Few things I learned.
Before checking and spending many hours chasing your tail check to see how true your lathe is cutting.
My lathe ways are short and the bed is solid. When my friends dad checked it out he said twist will be minimal on a short stout lathe like mine.
Took his advice. Get the lathe clean , adjusted and repair anything worn or broken.
My lathe is level by carpenters standards. Lol.
Plan on going a step ahead and get my lathe aligned best as possible

Just compare your ways readings from end to end an few points in between. As mentioned keep the same orientation

The saddle ? Can you influence the saddle by the lock or gib adjustment?

 

[kickback1122]

If I tighten the gibs on the compound to the cross slide ways what type of change would I get in the saddle if I had a twist?

 

[Jake M]

I finally got the tool to level the new-to-me lathe.

First and foremost, have you calibrated that level? It does NOT take fancy equipment to do it, but it must be done...

I thought the level was close enough for hobby machine, but when I rested the lev

The question, is this disparity something to worry about? Is this normal? is this adjustable?

el on the cross slide, I was surprised.

You're not building a stud wall out of two by fours... You don't care about level, true, or plumb. The reason a level is a valuable tool for "leveling" a lathe is that it is a repeatable datum which you can transfer to any part of the lathe. That's it. Even if your bubble was all the way to one side of the scale, so long as it' stays the same across all measurements, you've accomplished the goal.

The question, is this disparity something to worry about? Is this normal? is this adjustable?

No. No worries at all. What seems huge on a high resolution display (even if it's a graduated bubble display) is actually approximately equal to nothing. Resolution does not equal severity.
Rule number one when dealing with a level- Consistancy. Gloves are good practice with "fussy" levels. Readings with "fussy" levels should always be consisitant. That is, ways to ways, and nothing else. Start with a clean sheet if you're going to be on the carriage. Then ONLY measure from the carriage. Dont' touch or disturb the level, just move the carriage. (That's complicated geometry there, and if there's ANY wear in the ways, it's complecated cubed. Just make the measurements consistant to each other. The fussier your metrology department gets, the more you'll have to become comfortable with tolerances, and the more you'll realize that nothing (absolutely nothing) is actually perfect.

Thank you all for the input.

I sat the parallels on the flat ways and took the readings and yes, the level is off compared to the reading taken on the top of the V ways.

That's a very valid way to get a measurement from a place where the level can't rest. Do not forget however that you're not measuring the level of the lathe, you're measuring the level of the average surface where the first two parallels rest, plus any taper that's in the cross ways parallel... Nothing is perfect. Nothing.

Step one would be to calibrate that level. (Still not sure, you may have done this...).
Step two is no longer to rotate the level, but to leave it be. Move that whole assembly up and down the lathe without disturbing it. Easier said than done probably. Or plenty close is to make sure that you NEVER swap positions of the parallels. Scribe the parallels with a sharpie mark so that you can put the assembly back together as close to exact as it can possibly be. Don't flip or rotate the level.

You don't have to really overthink levels, but don't under think them either. Levels measure EVERY contributing factor that affects their rest position. Best practice is to find ONE setup, and go with that.


Quick story- I'm working on a widget downstairs in the basement. In Vermont. In the winter time. I live in an area where the weather, seasons, sun exposure, etc typically lead to a frost line between three to four feet... Things move. I've got a 9 inch South Bend with a four foot bed. It "measures" the movement in the concrete basement floor over quite some distance..... I'm making a piece for work, it's 13 inches long, with a critical dimension of about two inches on each end. The middle "should" be the same size, but it's irrelevent within reason. What an opportunity. I found 0.006 inches of taper over that length. I'm not surprised. I did "level" the lathe when I first got it, but having had it over enough season changes, this was my opportunity to remove a twenty five cent shim (one quarter) from the left front bench leg, and place two twenty five cent shims under the right front bench leg. That reduced the taper to 0.0017 over 13 inches. As the bench "relaxes" over a day or two (maybe less... I don't use it all day, every day...), I expect that'll settle in and I will have overshot the target and will have the opposite taper by about 0.001 or so once it's settled. Either way That's way good in my world. That'll make my 2 inch long bearing fits all day long. Leveling? I finally got a fussy level. My fussy level does not entirely agree. It WOULD have gotten me closer than I was when I started, but it would not have gotten me to where I am, and remember, I still can do better... If I choose. What will it get me? What are you making?

Use the level for what it is. Make it do what it does. Make it work for you. But don't let the level take you on a path that leads you down a rabbit hole. You (almost) certainaly will want to tweak a little after the final leveling is done. The level, being a datum, gets you a reference point that you do not have on an initial setup. It gets you close enough that you can identify the presence of, or lack of other alignment issues, so that you can make the machine cut as well you need it to, and/or as well as the machine is capable of. Whichever one comes first.

 

[mac1911]

If I tighten the gibs on the compound to the cross slide ways what type of change would I get in the saddle if I had a twist?

I cant see your level well in your pictures but it looks like your comparing the longitude level of your bed to the top of the saddle/compound ?
If im seeing the bubbles correctly
Your method/level is showing your cutting tool woud be dipping low ?
Are you have any issues when cutting?

How long have you had the lathe?

 

[mac1911]

First and foremost, have you calibrated that level? It does NOT take fancy equipment to do it, but it must be done...





You're not building a stud wall out of two by fours... You don't care about level, true, or plumb. The reason a level is a valuable tool for "leveling" a lathe is that it is a repeatable datum which you can transfer to any part of the lathe. That's it. Even if your bubble was all the way to one side of the scale, so long as it' stays the same across all measurements, you've accomplished the goal.



No. No worries at all. What seems huge on a high resolution display (even if it's a graduated bubble display) is actually approximately equal to nothing. Resolution does not equal severity.
Rule number one when dealing with a level- Consistancy. Gloves are good practice with "fussy" levels. Readings with "fussy" levels should always be consisitant. That is, ways to ways, and nothing else. Start with a clean sheet if you're going to be on the carriage. Then ONLY measure from the carriage. Dont' touch or disturb the level, just move the carriage. (That's complicated geometry there, and if there's ANY wear in the ways, it's complecated cubed. Just make the measurements consistant to each other. The fussier your metrology department gets, the more you'll have to become comfortable with tolerances, and the more you'll realize that nothing (absolutely nothing) is actually perfect.




That's a very valid way to get a measurement from a place where the level can't rest. Do not forget however that you're not measuring the level of the lathe, you're measuring the level of the average surface where the first two parallels rest, plus any taper that's in the cross ways parallel... Nothing is perfect. Nothing.

Step one would be to calibrate that level. (Still not sure, you may have done this...).
Step two is no longer to rotate the level, but to leave it be. Move that whole assembly up and down the lathe without disturbing it. Easier said than done probably. Or plenty close is to make sure that you NEVER swap positions of the parallels. Scribe the parallels with a sharpie mark so that you can put the assembly back together as close to exact as it can possibly be. Don't flip or rotate the level.

You don't have to really overthink levels, but don't under think them either. Levels measure EVERY contributing factor that affects their rest position. Best practice is to find ONE setup, and go with that.


Quick story- I'm working on a widget downstairs in the basement. In Vermont. In the winter time. I live in an area where the weather, seasons, sun exposure, etc typically lead to a frost line between three to four feet... Things move. I've got a 9 inch South Bend with a four foot bed. It "measures" the movement in the concrete basement floor over quite some distance..... I'm making a piece for work, it's 13 inches long, with a critical dimension of about two inches on each end. The middle "should" be the same size, but it's irrelevent within reason. What an opportunity. I found 0.006 inches of taper over that length. I'm not surprised. I did "level" the lathe when I first got it, but having had it over enough season changes, this was my opportunity to remove a twenty five cent shim (one quarter) from the left front bench leg, and place two twenty five cent shims under the right front bench leg. That reduced the taper to 0.0017 over 13 inches. As the bench "relaxes" over a day or two (maybe less... I don't use it all day, every day...), I expect that'll settle in and I will have overshot the target and will have the opposite taper by about 0.001 or so once it's settled. Either way That's way good in my world. That'll make my 2 inch long bearing fits all day long. Leveling? I finally got a fussy level. My fussy level does not entirely agree. It WOULD have gotten me closer than I was when I started, but it would not have gotten me to where I am, and remember, I still can do better... If I choose. What will it get me? What are you making?

Use the level for what it is. Make it do what it does. Make it work for you. But don't let the level take you on a path that leads you down a rabbit hole. You (almost) certainaly will want to tweak a little after the final leveling is done. The level, being a datum, gets you a reference point that you do not have on an initial setup. It gets you close enough that you can identify the presence of, or lack of other alignment issues, so that you can make the machine cut as well you need it to, and/or as well as the machine is capable of. Whichever one comes first.

Funny you mention weather and changing conditions.
My friends dad is a retired machinist and also repaired lathes.
He heard I picked up a lathe and wanted to check it out.
He came over and gave it a look and gave me the thumbs up. Said it needs a deep cleaning and go over ever nut bolt screw adjuster ectect.
I asked him about level .
He chuckled and said get the bench level and do the clean up.
Make some stuff and after some time we will talk
.
He went on to explain my lathe is in a 12x16 shed un heated ( floor was over built by me) over a stone platform. This thing is going to twist and move with the seasons.
So now about a year later im making more accurate stuff and noticing issues with taper.
Called the Gent and he says now we need to see where that taper is coming from
Twisted ways, crooked gear head , tail stock or ME.

 

[Jake M]

Called the Gent and he says now we need to see where that taper is coming from
Twisted ways, crooked gear head , tail stock or ME.

All of that, and three thousand other things..... It sounds like this fellow is going to take good care of you. But those are the four biggest bumps in the road right there. Taking those one at a time most if not all of the other stuff will sort it's self out. "As simple as possible, but not simpler". The REAL trick is finding and keeping the boundary between those two.