Thread: Best Method for Aligning Table Rotation

Hi Ray
I just made my cylinder squares on the lathe, you can do the same.
All you need to do is machine a piece of pipe on the out side check it measures the same all along end then face off the end, then you have one. I made one 55 x 130mm and the other 75 x 150mm out of pipe I had laying around. After making them I turned them around and faced the other end. I painted the inside as well as the untrue end so I don't get mixed up with the Wrong end. You can either do that or centre pop the untrue end.
When clamping it in the vise use a solid round vertical on the untrue end so so the true face sits properly when tightened.
Dave
PS
Make sure you keep them well oiled or they will rust in no time.

I am still totally lost in the explanations given to align the table with the Y axis.

As I have allready made the mistake in a prior post of thinking that the Table rotated independant of the Leadscrew for the X axis.

The Y axis has not been moved from what I can understand.

The Y axis should still be in alignment with the Horizontal spindle.

The table has or will be rotated.

The Table or X axis after moveing needs to be aligned to the Horizontal Spindle.

I would take a guess(bad thing) and say that the Horizontal spindle and Y axis are Square to each other,I would think that the only missalignment here would come from wear or incorrectly adjusted Gibs.

I would also think that the Knee would be Square to the Main coloum.

The Main coloum has from what I can see at least four machined surfaces on it.

The problem I have is still trying to understand why a Dial Indicator placed on one of these machined surfaces can not be used to align the table back to Zero.

From what I have read the Mill has 600mm of Longitudinal or X travel,this should be more than enough to be able to get an accurate alignment.

The way you are describing is the trap I fell in when I bought the first mill, but I found all my jobs were not square.
After that I aligning the table perfectly square with a square like Ray did, I found that every one of the 4 ways had a different reading on the dial indicator.

Like I said earlier I think they machine the knee ways to what ever, then get the alignment of the Y axis with machining the Y axis ways to suit.
It is the only thing I can think of as 2 of the mills I have set up, have had different height knee ways when the table was perfectly square.
On a quality machine this would probably not be a problem and your method would work, but not on these mills.

It has only been recently that I worked out the method I described to Ray. Like him I was looking for an easy way to align it with little or no error.
Using the square to set it up was a pain to say the least and the accuracy was only over the length of the square 150mm, this way is over 300mm which is twice the accuracy.

Hope that helps,
Dave

Originally Posted by pipeclay

The problem I have is still trying to understand why a Dial Indicator placed on one of these machined surfaces can not be used to align the table back to Zero.

This diagram may help... As you can see in it as the table moves the distance it is away from the column does not change. The mistake you are making is you think the table is still moving at a right angle to the column...





The way I would align it is like this... Put an angle plate on the table...Then do as you suggest put a dial indicator on the column and dial the angle plate in so no movement is indicated on the indicator.. This then means the angle plate is aligned exactly with the X axis ways...

Next put your tramming device in the horizontal spindle.... Now tram to the angle plate, adjusting the table angle as needed.... This will align the spindle at right angles to the table...

Thankyou for the sketch,sometimes its hard to think outside the box.

Here is a picture of my tramming tool... As you can see it is a simple home made device...None of the dimensions or angles are critical to make it work.. (clickable pictures)