Big Lathe Turning a Taper, Leveling Questions

wgnrr1 · Nov 8, 2012

My 25N Monarch just started turning a taper. Held good for 2 years, but needs leveling again.

My question is this:

Should I level off the ways as I was learned years ago, or can I just put the level on the compound slide and level from there? Logic being that the cariage can be moved more accurately than all the blocks and parallel. Am I wrong in assuming this.

I know there is no easy way out of leveling a lathe of this size. Took a month to get it good the first time.

Josh

Shadon · Nov 9, 2012

The compound is a good place to start, it can indicate what happened and where the ways need to be checked, you have to ask yourself "what changed?" are we talking about a sinking concrete slab here? Or material in the gibs or ways?

Theres a lot to look at, draw it on a piece of paper with the readings from your master level and make a "map" this helps visualize the senario.

Edit: check your tailstock alignment first!

HuFlungDung · Nov 9, 2012

First, make sure that the cut you are taking when checking your lathe for taper, is a very light cut, with a very sharp tool, and that your chuck jaws are bored straight and true in a preloaded setup that creates real parallelism with the spindle axis when the jaws are clamped tight on a true workpiece.

Take a cut on a couple of journals about 6" apart (on maybe a 1.5 to 2" bar diameter) and measure the diff. If the outermost end is measuring small, then you can visualize that the carriage is coming across at an angle from the right back corner (tailstock end) to the left front (at headstock). To fix that, adjust the rear levelling screw at the tailstock end, lifting that corner a tad.

Take note of how much you adjusted the levelling screw, and then take another test cut, and see how much it affected the taper. A couple more adjustments, and you should be close. Shouldn't take a month to get right, more like 15 minutes.

The level is used just to make sure the coolant flows the right way in the chip tray

Tyrone Shoelaces · Nov 9, 2012

A month to level a lathe ! I don't believe it. Is the bed that long you need to take account of the earth's curvature ? Or are you member of a sect that only allows work between the hours of midnight and one am ? More seriously, Is your lathe a) on a proper foundation, b) bolted down to the above ? Regards Tyrone.

wgnrr1 · Nov 9, 2012

It took a month the first time because I was only in the shop once a week, and the machine was a bit twisted. Previous owner did not even use it, just bought it and let sit for 5 years.

The lathe is in the corner of the building, so I am asuming the concrete shifted. Had this same problem at a former job with the 48" American. Had to level every 6 months.

I will start on it on Monday, have a job to finish on it next week.

Josh

Tyrone Shoelaces · Nov 9, 2012

Hi Josh, you still haven't said wether it's bolted to the concrete or just sat there. Even four days is a long while to level a lathe unless it's a 50 ft long behometh. Regards Tyrone.

Mark McGrath · Nov 9, 2012

Tyrone Shoelaces;1911090} Even four days is a long while to level a lathe unless it's a 50 ft long behometh. Regards Tyrone. [/QUOTE said:
Where were the Behomeths built ,Tyrone.Never heard of them before.

Mark.

Tyrone Shoelaces · Nov 9, 2012

I can't believe that Mark, I thought you'd know that the prop shaft for Noah's ark was turned on one ! Famous Babylonian machine tool builders. I P.M.ed you the other day, least I thought I had. sorry for the slight high jack guys. Regards Tyrone

John Garner · Nov 9, 2012

Josh --

There are differences of opinion on whether the level should be on the ways or on the carriage. The job can be done either way, but I'm more inclined to favor the ways only until the carriage is installed, and then using the carriage. One of Mitsubishi's "installation engineers" showed me a clever trick: Use two "Tootsie Rolls" of oil-mixed clay (aka plasticine) between the carriage wing and the base of the level to 1) help hold the level in place, and 2) adjust the level's position to roughly center the bubble in the graduations by pushing down on the level body and squishing the clay slightly.

John

Rob F. · Nov 9, 2012

John Garner said:
Josh --

There are differences of opinion on whether the level should be on the ways or on the carriage. The job can be done either way, but I'm more inclined to favor the ways only until the carriage is installed, and then using the carriage. One of Mitsubishi's "installation engineers" showed me a clever trick: Use two "Tootsie Rolls" of oil-mixed clay (aka plasticine) between the carriage wing and the base of the level to 1) help hold the level in place, and 2) adjust the level's position to roughly center the bubble in the graduations by pushing down on the level body and squishing the clay slightly.

John

I am missing something here. If you use the tootsie roll clay to adjust the level to be level isn't the machine still out of level? I dont see the benefit of shimming the level to read level when the machine isn't. Please help me wrap my head around this, I am needing to level my new 1942 monarch next week.
Thanks
Rob

rke[pler · Nov 9, 2012

Rob F. said:
I am missing something here. If you use the tootsie roll clay to adjust the level to be level isn't the machine still out of level? I dont see the benefit of shimming the level to read level when the machine isn't. Please help me wrap my head around this, I am needing to level my new 1942 monarch next week.

You (usually) don't need the lathe absolutely level, you just want the bed at the same angle all the way among it to eliminate twist. Absolute level is useful when you're rebuilding , kinda level is usually needed for oil sumps and no twist is needed for turning straight.

Tyrone Shoelaces · Nov 9, 2012

On a serious note all the usual authorities recommend you level the bed in both planes first and foremost. I'd agree with that advice. Regards Tyrone.

Rob F. · Nov 9, 2012

rke[pler said:
You (usually) don't need the lathe absolutely level, you just want the bed at the same angle all the way among it to eliminate twist. Absolute level is useful when you're rebuilding , kinda level is usually needed for oil sumps and no twist is needed for turning straight.

So get the lathe close and use the clay to get the level to read absolute level on the carriage and make sure it stays there as moved back and fourth? I understand the leveling is mainly to insure there is NO twist in the ways.
Rob

Limy Sami · Nov 9, 2012

Tyrone Shoelaces said:
I can't believe that Mark, I thought you'd know that the prop shaft for Noah's ark was turned on one ! Famous Babylonian machine tool builders. . Regards Tyrone

And what a POS they were

Mike C. · Nov 9, 2012

Couple of questions not asked... how much taper, and how long a bed? Also, have you pulled the tailstock off and cleaned out the chips that are hung under there and probably causing your taper? Lathes with huge tailstocks often get neglected in this department.

The company owner decided to line up the big Meuser at work the other day because it was sitting a little crooked. He nudged the tailstock end over with a forklift. Did I mention this machine has a 20ft+ long bed and is actually a 16" frame machine raised in sand to 48"? I just ran a job 17ft long on it... .090 taper. Within .005 at each end, but big right in the center where a leg is.

wgnrr1 · Nov 10, 2012

I put a level on the compound and moved it end to end today. Not a master level, but a Starrett 98. My master is at a friends shop 100 miles away. Not much out of wack on the ways, but the headstock is on a seam in the floor. The only place I can put the machine is on that seam. The headstock moved a little, enough to give me .005 taper over 1 foot. The tailstock was never mentioned and was not an issue. My problem was boring a large tube.

The machine is not bolted down. I have ran many large lathes that were never bolted down. I honestly do not see any benefit unless you are turning large out of round parts that create excessive vibration.

This is my first year in business for myself with this shop, I have owned a shop several years back. I have outgrown my building very quickly, and will be adding on in the spring. I plan on pouring 12-18" thick floors under the monarch and the HBM. This should cure most problems with settling and shifting.

To get back to the original question, some of you guys verified what I suspected. I did level the bed off the compound, and worked very well, even without a master level. I will be getting my level next week and finish up the job.
Josh

deadend · Nov 10, 2012

Bore and turning can give you a world of difference, do you get the taper when you turn? Are you boring more than a foot? Rigidity of the bar, length of the bar ect.

nel2lar · Nov 10, 2012

Tyrone
Then they would be using lazer and level it in just an hour.

gmatov · Nov 10, 2012

I had Behemoths, they were not uncommon , back in the day. They were Niles, Bethlehem and the like. 60 foot and longer, 100 inch swing. I have no idea if we still have any, sold them all to China, at a dime on the dollar.

Mark, all them "Behemoths" were built in the USA.. Ingersoll made some great machines. Cincinatti made some fantastic machines. Many of you own them.

George

Tyrone Shoelaces · Nov 11, 2012

gmatov said:
I had Behemoths, they were not uncommon , back in the day. They were Niles, Bethlehem and the like. 60 foot and longer, 100 inch swing. I have no idea if we still have any, sold them all to China, at a dime on the dollar.

Mark, all them "Behemoths" were built in the USA.. Ingersoll made some great machines. Cincinatti made some fantastic machines. Many of you own them.

George

I've got to disagree there George, plenty of " Behemoths were made in the U.K. and Europe.

To just to return to my usual hobby horse. If it's a big lathe ( or a Hor bore ) if it isn't bolted down you'll spend valuable time either re-levelling the machine regularly or trying to compensate for alignment errors caused by your poor installation. I never cease to be amazed that guys think you can just drag a machine into a shop, chuck a few shims under one corner, and away you go !
I sympathise with the OP, if you're just starting out in business spending your hard earned cash on concrete and rag bolts is probably not seen as good investment. I can understand that line of thought , but to me it's a false economy. On a large machine a good foundation is an integral part of the machine.
Regards Tyrone.

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