Adjusting Lathe Level

W

wnroscoe

Guest
I know this is old hat for the professional machinist/gunsmith here but just a friendly reminder for all of those that have recently purchased the small home/shop lathes. About twice a year I try to check my lathe for level and the way it cuts, taper or no taper. Today I was making a set of bushings and noticed .0006" taper, fat away from the chuck. I chucked up a piece of 1" stainless bar stock and made a .010" cut over 6". Bam, .0006" taper, fat away from the chuck. I raised the front right corner up to remove the taper and got it cutting with no taper. I also noticed that the concrete had actually settled more than I thought it would have. The leveling pads were letting the lathe rock a little. When I first set the lathe up with a machinist level I had to raise the front right corner slightly for a zero taper cut.

Last fall when I checked the lathe with a test cut it was fine, now that summer is here it moved. I thought I would share this with you just to put the thought in your mind, check your lathe periodically both for level and with a test cut to see if taper is present or not. Good luck and thanks to all that have shared info with me.

William
 
If you are trying to do really close tolerance work between centers it is best to check for level just before that job, even if you just leveled it last week. Level, per se, is not critical but twist is.

The lathe bed can be high or low on either end and do precision between centers work as long as there is no twist (crossways leveling).

This only applies to 4-point or 6-point, short bed lathes. When you get into larger lathes with 8 or more leveling points and a center distance of over about 5' then the game changes as to leveling.
 
Just curious William............what size lathe are you using? By the way...this post is certainly a great reminder for all.

Dave
 
I check my equipments level and alignment when the seasons change due to temperature/humidity changes can effect the properties of your concrete pad.
 
Same deal here. I don't use my lathe in the winter (no heat) and I end up leveling it about 3 or 4 times a summer and like Jerry says, I check each time I'm going to work between centers. Thinking pretty hard about grouting it in but am afraid if things change it would be major work to correct it.
 
Alex,

Here's the deal, the earth will always be moving so the concrete that our lathes sit on will be moving with it taking our lathes with it. There's absolutely nothing we can do to stop or prevent it. When I purchased my lathe I also purchased the leveling pads from MSC, it's always going to be easy for me to make adjustments as needed. I think this is just one of those things that comes along with it, preventative maintaince if you will.
 
Roscoe

You should live in Houston, which is a huge re-claimed swamp.
All of our large machines sits on it's own reinforced pad. Our two biggest,the 44 ft Leblond and the 32 ft Lehmann sit on 4 ft of reinforced concrete.
You would think they would stay put. But, we have to check the level at least once a quarter. Let it rain for about 4 or 5 days, or go a couple of weeks without, and you can see the difference.
We use a precision Starret Transit to shoot these lathes in. Then we take the twist out with a level mounted on the carriages........jackie
 
Jackie

I hear tell that machines in the San Francisco Bay area are quite a chore to maintain as well. 32' & 44' machines remind me of a story I was told by an older friend of mine. He served in the Navy and happened to be at one of the shipyards one day. The Lathe being used to turn a propeller shaft for one of the Destroyers had two men operating it. One that sat in a control both above and one down in the chip pan wearing a hard helmet and Kevlar trench coat :eek: He said some of the chips could weight as much as 5lbs. when they would hog it off.

He's one that says the gunsmith lathes are toys, I guess so comparing.
 
wnroscoe said:
Alex,

Here's the deal, the earth will always be moving so the concrete that our lathes sit on will be moving with it taking our lathes with it. There's absolutely nothing we can do to stop or prevent it. When I purchased my lathe I also purchased the leveling pads from MSC, it's always going to be easy for me to make adjustments as needed. I think this is just one of those things that comes along with it, preventative maintaince if you will.
Click to expand...

My lathe is an early 90's Tiawanese job, 1 metre centre's. It has two posts, head post has 4 bolts, tail has 2. These bolt through the tray onto a square tube steel frame which bolts down to concrete. To level this arrangement I use shim packs under each bolt and between frame legs and concrete, add or subtract shims as needed. Works, but it's tedious in opperation, and I thought some sort of jacking screw might be better.
What are these leveling pads from MSC and how do they work.
Or, does someone else have a good system of jack screws.
I would like to be able to adjust and not have everything change when re tightening bolts , like it does with the shims.
Just for interest, the lathe name is G TECH model 1440 G.
Probably same machine but different name in different countries.
 
Thanks wnroscoe. These go between frame legs & floor, and what, there is no need to bolt feet to concrete ? Looks like with that 4'' diam foot they should be stable, as long as the lathe is heavy enough.
 
blunt shooter said:
Thanks wnroscoe. These go between frame legs & floor, and what, there is no need to bolt feet to concrete ? Looks like with that 4'' diam foot they should be stable, as long as the lathe is heavy enough.
Click to expand...
When I bolted my lathe to the floor it vibrated very badly. When I put the leveling pads on it and let it free stand, it ran very smooth, no issues. Yes, the pads just mount in the existing holes, you'll need one extra nut and two washers per pad though. I only used the outer most four holes although my machine had eight mounting holes. The pads I listed are not the exact pads I used but look identical to what I have.
 
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THANKS AGAIN. wnroscoe

Very interesting that you bring in the vibration issue, because you just may have solved another problem for me. Also had a harmonic type thrum vibe ,if you know what I mean. Tighter V belt tension got rid of that, although then the belt gets some sort of hump in it if left tight while not in use for a week or so. Belt on belt off betwix use. Another thing that I don't need. It will be interesting to see if after fitting leveling pads this can be controled, because you see, it might not so much need the tight belt, as to free stand.

A side issue but on the same note. I have a Tormek tool grinder that drives with the weight of the little electric motor pressing its 5mm shaft onto the outside of a rubber tyred wheel which is 117mm diam. This gives a grind stone rev of 120 rpm. Now if this wheel is not taken off the machine between uses, the pressure of the motor shaft laying on it will leave a little groove in the rubber. This translates to a notch appearing on the stone's surface while grinding, from the bump bump----bump bump in the drive. I put this wheel in the lathe and trued the rubber,now it runs smooth and doesn't wreck the stone
 
Leveling solution

See picture.
 

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