Milling Machine Tramming

Hi

I have now done some milling on my SX2+ milling machine that I bought lately. I have done some measurements to. Using a Dial Indicator I can measure that the "noding" (Y-axis allignment) is about 0.119 degree, calculated using trigonometry from the deflection of the DI (0.25mm over a distance of 120mm travel of the Y axis).

The question is: Should I try to fix this. The column is bolted to the base. If I have to adjust it I must try to insert some shims between the base and the column. I anticipate it will be difficult to do and to get it right.

Has anybody any experience in doing this kind of tramming work on a SX2+ or similar machine?

Kind regard, Nyrup

Hi There

Are you sure the column is out?

Could the quill be out of alignment with the column?

I would put a square against the column from the table and check with feeler gauges.

I have not done this mill but did a Dore Westbury a few years ago with no problems.

regards David

Hi, are you actually tramming the head, ie swinging a DTI on the end of an L shaped bar through 360 degrees? If the spindle is at 90 degrees to the table the DTI reading will be constant in any position.

Tony

Hi

Thank you for you answers.
I must admit that I did not use an "L-bar" in the collet/quill. I used a magnetic base fixed to the underside of the head and traversed the Y (topslide) of the X-Y cross table.
I guess that perhaps I in that way measures the cross table and not the head/ column alignment.

When I get the time (hopefully in the weekend) I must try both the square method and the L-bar method. I think I can unscrew the bar-pillar system from my magnetic base and use that in a collet or the drill-chuck.

I'm not sure that I have shims that is thin enough. I have a roll of 0,1mm shim. Perhaps I could use thin paper as shim? Would that feasible?

Kind regard,
Nyrup

Another thing to check is the adjustment of the gib strip for the milling head. If this is slack the head may well nod forward. Also make shure that the head is locked when you make your measurements.

Roger Woollett

Hi there

That sounds like the table is out in the Y axis, not necessarily the column or spindle alignment.You need to put a parallel onto the table in the Y axis and shim up one end until the indicator reads true while traversing across the Y axis and then check the spindle by rotating an indicator at 180 degrees from the front to the back of the parallel. Then you will know if the spindle is square to the head.

regards David

Hi

I have now investigated the tramming further.
I must say that as it looks now it does not look good at all with my Sieg SX2+ !

I'm not done with all your recommended tests, but partly so, my conclusion is that the surface of the x-table were at an right angle to the column but the y-axis motion or traverse were not at at an right angle to the column. The result were that the distance from the tool in the spindle to the work piece were not constant when traversing the y-axis.
I have now shimed column/ base connection so that the y-axis traverse is at an right angle to the column and thus the distance is the same from the spindle to the table during the traverse.
The downside is that the table surface is no longer at an right angle to the column.
The head tramming is out too. I have done the "L-bar test".
Of course when the table is not at an right angle to the column I can not expect it to be parallel to the head or the spindle to be perpendicular relative to the table surface.
As the only way to correct this seems to be both a surface grinding of the table and a process of dismantling the total milling head assembly and trial and error with shimming in the head mounting when reassembling the head I am either looking forward to a very tedious and time consuming job or trying to live with and working around the shortcomings of the milling machine.

I wonder if every small from Sieg is this inaccurate or I am expecting to much - or perhaps overlooking something or misinterpreting something.

Yesterday I was milling some steel in the process of making some more T-nuts.
It looks like the work piece is now being milled to an reasonable state of right angle.
Something that was not the case before the shimming.

Kind regard,
Nyrup

Is this machine new? If it is, then get in touch with the supplier and get them to exchange it for a better one.

If you have to repair this for yourself, then you will need to work through the alignments in a methodical way and try and stay away from shimming (ugh, horrible way to fix something!), as much as you can.

Martin.

Hi There

I would machine a plate on the table to sit the vice on. Only needs to be about 1/2 inch think.

Aluminium would do.

regards david

Nyrup,

Since the Sieg SX2 is fairly new ..... when you got the machine did you strip it down, to clean out all the shipping gunge, casting sand etc? (Arc have instructions for this process for several of their machines on there Website)

Dave

Hi

Once again, thank you for your answers.
If I were living in England in traveling distance from Arceurotrade, I am sure I would drive by and talk with them. If I had to by the Sieg C3 and SX2+ here in Denmark it would probably have had the name Rothwerk and have been sold by people who had not got a clue of what they were trading... ;o)

I bought from Arc because even with postage included money was saved compared to fx. Rothwerk and the SX2 with R8 spindle is not available at all.
I were a bit anxious about the fright. Would the machines be damaged.
Well, on both the lathe and the milling machine the bottom of the plywood case did not withstand the heavy machine during the travel. In both cases the plywood cracked and was splintered but the band around the case did hold it in place and no damage seems to have happened with the machine itself, so i guess that it is not this fright problem that is the course of inaccuracy.

I have already dismantled, cleaned and lubricated the complete X/Y table.
Also I did that on the fine-downfeed (z-axis) mechanism.
The head I have left on its own as everything seems to function ok and I assume that the bearings in the spindle are closed sealed entities and as the SX2 is belt driven there is not much to do inside the milling head.
​​I did however encounter a problem with the x-travel. At the leftmost end of the table it binded so much even after cleaning and lubricating that I clearly had to do something about it.
I "bit the cake" and used some sanding paper - I did not have any emery cloth - and sanded the dovetail in the left end. In a matter of an hour or so I managed to get it sliding smoothly and the surface were considerably more smooth than the original machined surface from the Sieg factory.

The machine was, as you might already have guessed, bought new. But as the fright is expensive and troublesome the possibility of returning the machine is not an option.
All of this I did consider even before placing my order. I took the chance and did perhaps not exactly win the lottery.
I am not keen to make irreversible changes to anything and certainly not when I am not sure how to do it and if I am making more damage than remedy.
Therefore I think that I do have to stick to shims and probably an aluminium plate that I can machine to a right angle and level workspace on the milling table.
Aside from these troubles I am happy with my purchase.
Had it not been for the Sieg factory I probably would never have fulfilled my dream of a metal lathe neither a milling machine.

Kind regard,
Nyrup

If you bought it from ArcEuro, email Ketan for his comments before you go any further.

No fewer than 7 potential errors exist in the Y axis.

1 The y axis slide on the base must be 90 degrees to tthe column

2 the table x slides must be parallel wrt the y axis slides

3 the x axis slides must be parallel to the table top

4 the head slides must be parallel to the column

5 the quill slide must be parallel to the head slides

6 the spindle must be parallel to the quill

7 the spindle taper must be aligned to the spindle.

On average positive errors cancel the negative ones but on probability sometimes they will all add up in the wrong direction.

No wonder the top machines cost a bundle.

"2 the table x slides must be parallel wrt the y axis slides"

perpendicular is more traditional

Though I have seen CNC mills based on "Hexapod" ...but these rely on machine computing to allow orthogonal input...not really mill ..more robot arm with mill spindle end effectors...

I am worried that you say you shimmed the column to keep the spindle to table distance constant. If you need to do that it can only meanteh table is not of cosistent thickness - this is an unlikely error.

How are you checking things? Can you post a picture or diagram to show exactly what you are measuring and the size of the errors?

Neii

Hi

Thank you for your concern and your comments.

I have thought more about this tramming business and come to the conclusion that "Stub Mandrel" mention: I can't shim the column to remedy the problem that I have.
Yesterday I did some more milling. I was making some T-nuts. It worked out very fine no problems at all. I did some check to of the column and the base.
It appears that the column is at an right angle to the ways of the base. The ways that the X-axis travel on is at an right angle to the column - or were till I shimed the column/ base connection.

So the problem must be in the remaining assembly somewhere.
I'm afraid that it will be almost impossible to fix that in a proper way - at least for me - by myself.
Perhaps I will contact Arc...
Well... Anyhow... It is possible for me to work around the problems and the SX2+ is very capable of milling in plain black steel. The material I have used so far.

Kind regard,
Nyrup

If you look about halfway down this thread you will see a good description of how to tram the head/column.

Russell.

Hi Russell

Thank you for your tip. I will surly remember the tip. I have been thinking of something similar but had not thought about removing the head- column assembly from the base and how much easyer that would be compared to lifting the head off the column and replacing it to measure. Also I have read about the method of averaging the measurements readings of the bar and gaining accuracy in that way. But I had forgotten the method. Surely it was good to get the memory refreshed!

By the way. I have been tinkering with the tramming since my last post and somehow I have slowly
managed to get the column/ base/ x-table to a right angle at a much larger degree of accuracy than before by shimming the column-base connection at some other points and with various thicknesses of shimming.
The funny thing is that this helped both on the column/ base/ x-table angle and did to a large degree also remedy the tramming of the spindle.

Now I will continue to use my mill and check how good or bad it performs.
I surely (think that I) know much more about how to tackle the tramming by now compared to when I started this thread.

Kind regard,
Nyrup