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04-25-2010, 10:45 AM #1
Where to place a level on slant bed Mori
I am trying so hard to upgrade the alignment of my Mori Seiki SL-1 CNC lathe while the machine electronics are broken. I want to check if it is level but don't see where to begin since it is a slant bed lathe. Does one place a precision 45 degree square on the ways at either end? I sure can't figure out what to do to even start.
04-25-2010, 10:53 AM #2
Did this on a Nakamura CNC lathe I had.... pulled the way covers back, used a sine plate upside down (so the lip on the normally top surface was catching on the edge of the box way). Think the one I did was set at 60º, but that doesn't matter, match what your machine is. Then I set the Starrett precision level (.0005" per foot accuracy) on top of that.
One word of caution, we had a machinery repair guy in once working on a machine and he was doing basically the same thing, borrowed my Starrett and proceeded to drop it on the ground..... they don't bounce well, and accuracy suffers dramatically so be careful while you have this whole rig perched on the machine.
04-25-2010, 11:12 AM #3
used a sine plate upside down...
Thanks Brian, I just found a post talking about a levelling plate for slant bed lathes. I have a box of stuff that came with the lathe and the plate is there. I did not know what the heck that thing was for. Now I realize what an important fixture it is! It is a plate mounted to a tool holder and so I just attached it to an empty slot on the turret at 12 o'clock and there is a nice flat surface to place the level! What a relief! I sure appreciate the past posts on the subject. One step closer to better machining if I could just get the electronic problem solved...
Now, what if the turret is not aligned. I am sure it is a bit off because it is set to the off -kilter spindle. I can see that it will still be useful for leveling from head to tail but if the turret is rotated, will it work well for front to back? I assume that it does not matter as long as the same angles apply at each end of the lathe since it does not have to be level but just not twisted. I am getting a taper of .005" per 2 inches of cut so either there is a large twist or an out of align headstock (another post on that problem is out there from me).
04-25-2010, 02:34 PM #4I am getting a taper of .005" per 2 inches of cut so either there is a large twist or an out of align headstock (another post on that problem is out there from me).
04-25-2010, 04:15 PM #5
04-25-2010, 04:27 PM #6
You oughta have a bracket to span the top and bottom ways as those brackets provide a place to check the beds front to back and left to right level and twist. Both Cincinnati Milacron and American Tools Slant bed machines came with these leveling brackets, not sure about other builders.
If you bought your machines used, they probably get lost in the shuffle.
I wonder if one of those "universal you can test and level anything rigs" that are sometime seen being used to level engine lathes would work... They amount to 2 levels set at 90 deg to each other and are mounted on rods with ball ends. These balls rested on the way surface and as you moved that rig the length of the bed you adjusted the leveling screws to get the bed straight. It might not have been level front to back, but at least this rig got them pretty level left to right.
Seems your talking about short machines here.
Just how long is the bed and how much Z axis travel does it have?
How many leveling screws does the machine have? And if you detected a twist in the bed, are the leveling screws in the right place to remove the twist? Do you have hold downs where the leveling screws are?
04-25-2010, 05:23 PM #7
My Cincinnati slant bed instructions say to run the turret as close to the headstock as possible and as far away from it as possible and make the leveling fixture level at both locations with the leveling screws. On mine that means running the turret up at high as possible to clear the chuck. I can't see that turret alignment will matter.
04-25-2010, 06:09 PM #8
I do have the leveling plate but no other jig to span the ways. This is a short bed lathe with only about 10 inches of z travel.
I find 6 leveling screws but I don't have them screwed into the floor.
Do you guys think in general that a Starrett 199 level is necessary to level all my machines or is the 98 going to work. I also have a BP, Matsuura mill, radial arm drill and automatic saw that could benefit from a good leveling job.
04-25-2010, 07:44 PM #9
The 199 is (IMO) a necessity in a shop. You can pick one up on eBay or buy new for $700 plus (last time I looked). The level can be calibrated to level by simply swapping it end for end until it reads the same both ways (if whatever you are resting on isn't level, you can always use feeler gages or shims on one end to get there eventually).
I personally think you'll have better luck with something that straddles the ways rather than relying upon the turret... who knows what sort of wear you might have close to the headstock vs. all the way at the back. Your issue of .005" per 2" is NOT the ways being twisted, at least I'd be very surprised if it was. They would have to be really out to get that sort of difference... and the Mori is a rigid little machine... so I suspect as you do, the problem might be in the head stock alignment to the bed.
Do you have a collet setup on the machine? Install a piece of good straight bar stock, maybe some centerless ground stainless or something and do some indicating on it and see what you find.
04-26-2010, 03:02 AM #10
Great, I will get a good level soon as well as some Thompson precise straight stock.
Is it ok to put metal pads under the leveling screws?
04-26-2010, 03:55 AM #11
Yes, I do. I bore a recess into the top for the screw so the screw can't walk off the pad from vibration.
04-26-2010, 06:47 AM #12
As Mud said, yes, they usually send small cast iron discs with a dimple in the middle so the screw centers in it. A piece of 1/2" steel stock with a drill dimple will work just as well.
I don't know that I'd spring for some Thomson rod... unless you have some laying around. Any piece of bar stock that isn't hot rolled on the outside should be pretty consistent and straight. Put your indicator on it and spin the spindle to see if it's running true, if it is, then all you need to do is run the turret back and forth and see if it follows the bar.... if it's not, then the axis of your spindle is not parallel to the axis of the bed. Where and what you have to do to adjust that, I wouldn't know on your machine.
I could see a good crash throwing a head out to the ways though... and I suspect some machines have a built in "safety" in this regard... too much impact and the spindle head rotates to keep it from really destroying things.
04-26-2010, 10:49 PM #13
The factory Mori leveling pads that the jackbolts sit on are cast iron discs about 4.5" diameter. The important part is the dished-out center, which is a radius. Pull out one of your jackbolts and look at the end. You'll want the pad to match that radius. If you choose to use just a drill-point or similar in the pad, insure that the angle mates well with the radiused end of the bolt, so there is no movement horizontally by the machine when it's sitting on the pads.
You can't twist that short little bed enough to cause that much taper, so I expect the headstock is angled. Not easy to knock out those old Moris. I've posted some details before on aligning Mori heads, turrets and leveling, using some tricks that have worked well for me. (They apply to most lathes.) You could search for them. I'd do it for you, but it's about to hit 1am and my brain is screaming "sleep dammit...NOW!!"
04-27-2010, 07:16 AM #14
Metaltech, I have reviewed your extensive posts and really appreciate your time and experience. My basic question still relates to the specific bolts for the headstock adjustment for the Mori SL-1. Should I be able to find a specific post?