Thread: The old "trimming the mill" question

Originally Posted by RayG

But since the mill itself can't be adjusted, you'd have to tram the vise with shims. Setup an indicator in the spindle so that it sweeps the vise jaws as the spindle rotates, Adjust until you get no change as the spindle is rotated.

Not so sure thats going to do anything........ if the tram is out sliming the vice wont fix that.................... I think. sure the vice will be trammed to the spindle but it wont be parrallel to the axis.....but the mill will still cut the same wont it?

Stuart

Originally Posted by Stustoys

Not so sure thats going to do anything........ if the tram is out sliming the vice wont fix that.................... I think. sure the vice will be trammed to the spindle but it wont be parrallel to the axis.....but the mill will still cut the same wont it?

Stuart

Yes, it won't matter that the table ways are at an angle to the spindle axis. So long as the vise is trammed to the spindle axis and the work is parallel to the vise.

Ray

Originally Posted by RayG

Yes, it won't matter that the table ways are at an angle to the spindle axis. So long as the vise is trammed to the spindle axis and the work is parallel to the vise.

Ray

I'm not seeing it.
If the spindle is out of tram and you move the vice to match the spindle, its now out of wack to the X axis. The "look" of the top face of the work is the results of the spindle angle to the X axis...... the angle of the vice and work piece wont change that.
Am I misunderstanding what you are trying to do?

Stuart

Hmm... ok take the vise away, for a minute. tilt the table 45 degrees.. ( if you could ) measure the distance from the cutter to the table. now run the table back and forwards. Does the distance between the cutter and the table change?

Ray

Hi Ray,
Do the same thing but leave the table flat and tilt both the head and vice 45 deg, they will be in tram with each other. But, the cut will be deeper at on end than the other (well at 45 you would just make a mess of everything). The only way to tram the head is to make sure the spindle center line is perpendicular to the X axis ways.

I would be judiciously scraping/filing the column to the base to get it in tram. The only other thing i can think of is shim it on the corners and inject something in the gap like an epoxy, or metal putty etc. Fill the damn column with concrete while your at it to add a little mass.

When fly cutting watch for more trailing cut as the leading cut comes off the work. This shows flex in the machine and a sign that for test cuts at least you need to go slower. The mill being in tram however will not change how parallel a machine part is-only how the cutter works and how square milled edges are, how square drilled holes are etc.

Ew

Hi Ewan,

Not quite....

The answer to the previous question you are thinking of is no change in the distance from the cutter to the table as the table goes back and forth in X.

Let me take it step by step...

Ok, now put the vise back on the table, still at 45 degrees, and clamp up a block of material in the vise, and take an X axis cut. Now clamp up the part you wish to work on parallel to the cut surface and you can machine as if the machine was trammed.

Now, what happens if instead of the block of material, I machined the same cut off the vise... any work I clamp to the vise parallel to the jaws will be in tram to the spindle.

Final step, instead of milling the vise, ( and ruining it's resale value ) I shim it instead by the same amount I would have removed had I milled it.

The only reason I'd even consider tramming the vise instead of the table, is on this mill it's not adjustable... hope that's confused everyone..

Ray

I think i follow but if the head is not trammed it remains not trammed, no matter what you do with the vice. If the LHS of the cutter is lower then the RHS, the LH will cut and the right wont, no matter if you are milling parallel or not....

Ew

Originally Posted by Ueee

I think i follow but if the head is not trammed it remains not trammed, no matter what you do with the vice. If the LHS of the cutter is lower then the RHS, the LH will cut and the right wont, no matter if you are milling parallel or not....

Ew

No both sides will be the same height in relation to the work.. imagine we used a big facemill to machine the top of the vise jaws, then clamped our work parallel to the jaws we just cut, both sides of the cutter are the same height in relation to the work.

Ray

Originally Posted by RayG

both sides of the cutter are the same height in relation to the work.

Only if you cut it with the Y axis. Tilt the head to 45 again, now make the cut with the Y, the vise jaws are at 45 and trammed. If you make the cut with the X though only one side of the cutter cuts, but your cut is concave.

Ew

Originally Posted by RayG

Ok, now put the vise back on the table, still at 45 degrees, and clamp up a block of material in the vise, and take an X axis cut. Now clamp up the part you wish to work on parallel to the cut surface and you can machine as if the machine was trammed.

Nope.
You may(should in fact) get a part that is parrallel*......but the tram still wont be right.
Changing the angle between the X axis and the top of the vice jaws doesnt change the angle between the X axis and the spindle. and thats tram.

*though I'm not sure what barons problem is.

Stuart

Originally Posted by Stustoys

Nope.
You may(should in fact) get a part that is parrallel*......but the tram still wont be right.
Changing the angle between the X axis and the top of the vice jaws doesnt change the angle between the X axis and the spindle. and thats tram.

*though I'm not sure what barons problem is.

Stuart

Yes, you are correct, the error is still there, and there's no easy way to get rid of it.. but you can machine a part "as if the mill was trammed"

I'm still thinking about what happens to Y... Ewan has confused me... I don't think nodding was mentioned earlier was it?

Ray

Not thinking about nodding, just using the Y to mill the vice jaws.....

Ew

Originally Posted by RayG

.. but you can machine a part "as if the mill was trammed"

No it wont........Doesnt matter what you do with the vice....the surface of the workpiece will exactly the same in relation to the X axis....only the bottom of the work piece will have moved a little.

I'm thinking you're talking about getting it to cut parrallel. I'm talking about tram.

Stuart

Originally Posted by Stustoys

No it wont........Doesnt matter what you do with the vice....the surface of the workpiece will exactly the same in relation to the X axis....only the bottom of the work piece will have moved a little.

I'm thinking you're talking about getting it to cut parrallel. I'm talking about tram.

Stuart

Yes, we are talking about different things..

I agree, by definition you can't tram it wihout changing the X axis or the spindle axis, but you can get it to cut parallel. ( well maybe, with this mill, I'd not be too sure... )

Ray