Machine Balance/Rocking Due to Weight Shifting from the Table

Hi
Got a problem. I was using the 2216 workout program to finally get a program running on my "new to me" VMC 40. The issue: when the table reaches the left or right side forward most point of travel, the weight of just the empty table was enough to cause the rear of the machine to lighten enough to almost lift the rear off the steel bar stock the machine rests on. (sorry for the run-on sentence) I can move the table to the front (full -Y) left or right, put my body weight on the machine and lift the rear. The machine sits on two pieces of CRS barstock situated beneath the leveling screws. It's strange because that is where the factory leveling is done. The only thing I can think of is my concrete slab is sloping enough that the center of gravity for the machine is further forward than it should be. The machine faces the garage door and my driveway also slopes towards the road. I will have to put a level on the machine and/or floor to see if it slopes foward excessively. Haven't gotten the machine leveled yet, just an FYI. However, I wouldn't think the floor could be that unlevel for this to happen. Your thoughts?

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Level the machine and adjust the leveling feet to all have the same load on each foot then I think your problem will go away. Depending on the weight of the machine, I normally use a 6 inch square x 3/4 thick chunk of steel as a pad under the feet. Depending on the type of leveling screws I might put a divot in the center of the 6x6 plate with a large drill bit just to keep it centered under the screw.

Worst case, bolt the machine to the floor if there is a provision in the machine base to do that. A standard residential garage floor is not really designed to handle that much concentrated load, but I have had good success with 10,000 lb machines sitting on mine.

I've got two bars of the cold rolled steel under the machine right now. They are as long as the machine's casting 18-24" or so, 1" thick and 2.5" wide. The machine is about 8400lbs. The leveling screws are just some studs with a hex socket on one end. The original owner had four individual blocks of steel under each screw. I though it would be a tad better to go with two bars instead of the individual blocks. I planned on pulling them back from under the machine to be a divot in them so the screws can sit in them. A user on practical machinist recommend that I not use the bars and just use individual blocks instead due to possible uneven concrete. However, I dont see how that would make a huge diffence being that I will still be using each leveling screw to individually adjust the corners of the machine.

I would cut those bars into pieces about 8 inches long and use one under each screw. Using a long stiff bar under two screws will not put the weight on the floor correctly, it will try to balance between the two screws. You need the point contact to set the machine correctly. The user on PM is correct.

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Originally Posted by Jim Dawson

I would cut those bars into pieces about 8 inches long and use one under each screw. Using a long stiff bar under two screws will not put the weight on the floor correctly, it will try to balance between the two screws. You need the point contact to set the machine correctly. The user on PM is correct.

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Ok. Will do. I should probably use a jam nut as well to help prevent the leveling screws from backing out, correct? Here is a pic of the leveling screws for the Fadal. Kind of primitive.
https://uploads.tapatalk-cdn.com/201...e3b7f663ab.jpg


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Leveling screw lock nut can't hurt. :)

You definitely want to use 4 individual pads. One of the original installers service tech Richard K. back when we were first building VMC's (1979 the VMC45) taught me a trick when he installed would actually get the machine surprisingly level with barely any effort. He would start with 3 points (tri-pod always level) Use the back 2 screws, and then he used a large 1" Dowel pin right in the front of the base casting centered between the 2 front levelers (the 3 points). And then just bring the 2 leveling screws down on the 2 front pads Evenly till the dowel would just slip out and wah-lah u will be real close to level.

Quote:

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Originally Posted by rodney247

You definitely want to use 4 individual pads. One of the original installers service tech Richard K. back when we were first building VMC's (1979 the VMC45) taught me a trick when he installed would actually get the machine surprisingly level with barely any effort. He would start with 3 points (tri-pod always level) Use the back 2 screws, and then he used a large 1" Dowel pin right in the front of the base casting centered between the 2 front levelers (the 3 points). And then just bring the 2 leveling screws down on the 2 front pads Evenly till the dowel would just slip out and wah-lah u will be real close to level.

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So I’m assuming the rear of the machine initially has to be risen up equally as much as the front is on the round bar stock. Otherwise I don’t see how this would work (for leveling front to rear that is).


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yeah you would have to put a plate under the Dowel the casting in the front of base is not straight across(originally the leveling plates fadal used were only 1/2 thick steel squares with a c'bore in middle so prolly only 3/8 thick where the leveling screw touched. And you want the fadals higher in the front so the coolant flows out the back. it doesn't have to be a 1" dowel it can be any size.(what ever works)