Tramming questions

R

raferguson

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I think that I understand tramming a little. What puzzles me a bit is how this works if the head does not tilt, and the column does not tilt. The column is bolted to the base, so I suppose that I could shim it until I got it right. I did one time fix a cutoff saw that would not cut right angles, by careful shimming. I have a large HF mill-drill.

I am thinking that I will just weld up a jig to chuck into the collet and then attach the dial indicator (or test indicator) to. I would just swing it around and look at the difference in the readings at four points.

Am I on the right track here?

Richard
 
This video may be of interest to you:


Ted
 
Yes - you are absolutely on the right track.
You will note that the Stefan Gotteswinter method was to use the epoxy to in effect end up with custom shimming of exactly the correct thickness, but made of epoxy. The machine main structures could be moved a little, and tightened to stay in the correct position until the epoxy had set. There are other ways if you don't want to go with epoxy.

The most routine tramming is easier. The tutorial from Quinn Dunki is handy. :)


 
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The fact is the factory doesn't do a consistent job of getting it right- some examples are right on and others are off a little
-Mark
 
One trick in tramming is to mark points on the table centered on the quill that correspond to the spacing of the 4 bolts that hold the column to the base. Take a reading at each point. Make your zero at the largest reading. Take another reading at the 3 other points and you will have the thickness of the shims needed at each of those points to tram the column.

The epoxy method has merit if you don't mind working with the stuff. Some people are highly allergic to epoxy. Pure epoxy is very brittle and will crack. It is also very runny. So you need to add thickeners to the epoxy. You want the consistency of peanut butter. You need to coat the base and the column with mold release wax or you will have a very difficult time trying to separate the two if you should ever need to remove the column from the base.
 
graham-xrf said:
Yes - you are absolutely on the right track.


The most routine tramming is easier. The tutorial from Quinn Dunki is handy. :)
Click to expand...
Thanks to all for their input. The Quinn Dunki tutorial seemed particularly good, I should follow her on Youtube or wherever.

I fabricated an adjustable jig, which seems to be working. I identified what I need to do. I am probably going to start with .004" on two corners and .008" on the other corner, as I found left to right and back to front misalignment. (Four bolts hold the column to the base). I will probably need to carefully jack up the head to get the shims in. I will loosen up all four bolts and then see if I need to use significant force.

But what about shims? I have used brass or aluminum in the past. I found nothing in my personal inventory other than a plastic bag that once held a shim. ;-) I suppose that I could use an aluminum beer or coke can, one source suggested that they were about .004 inches thick. Some of the vendors would like you to use their precut shims, no surprise. I am not 100% sure what size or even shape that I need, so inclined to cut my own with tinsnips. McMaster has a set of carbon steel shims for $30, brass for $40. (I live in a dry climate, so corrosion is not a concern).

By the way, in order to use the jig, I had to loosen the bolts and move the head down, but of course to use the mill the head will need to go back up. Maybe I should redesign the jig with a longer shank.
 
I have a similar mill and I ended up using tin foil under one corner because I didn’t have shim stock that thin not did I want to sacrifice any leafs from my feeler gauge set.
 
I am missing something here. Is not the table mounted to the column also?
 
The table is integrated with the base. The column is bolted to the base. It is a round column mill-drill with no provision for tilt or nod.
 
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