[Spooq]

Hi,

I've just run a fly-cutter and a 3/8 end mill over a ~2 inch cube of aluminium to tidy it up. Both left a ridge which I could feel with my finger along the edge of their cut. "No problem", I thought, this sounds like the mill needing to be trammed. I haven't done that since I bought it, and it has been hauled around a bit. In fact, I'm not sure if it has ever been trammed.

So I grab my DTI and some ground blocks, set them up to measure the x-axis... and it appears to be perfect. I do the same for y and again it is perfect.

Now, I'm slightly suspicious I'm doing something wrong, but I can't see what. I've watched NYCCNCs tramming video on YouTube, and I am doing exactly the same thing. My DTI doesn't have a very long arm, so that probably isn't helping. But if tram appears to be correct within a very small figure - is that likely after moving the machine twice? Wouldn't the move plus a different floor throw it off by twisting the stand slightly?

Something else I've just noticed too - if I turn the jog wheel full-speed +/- on the x-axis, occasionally it moves at a slower rate before speeding up. The slow rate seems to be the "second-fastest" speed. There isn't an intermediate acceleration, it just goes second-fastest, then after 1/2 second or so goes to full speed like it should. Has anyone else seen this behaviour? Edit - I strongly suspect the new USB hub I'm using is the cause of this!

Luke

Edit - I'm going to keep the DTI in the spindle, and run it up the side of a square on the table, and see if that tells me anything about the spindle-table relationship. I'll also run the DTI along the table surface and watch what happens.

[BAMCNC.COM]

Your not moving your table during tramming are you?

[Spooq]

Your not moving your table during tramming are you?

Nope.

The DTI didn't move when I traversed X and Y.

Testing with the square was a little bit less precise. I tried it three times and got different results.

I might be over-thinking this. Maybe the cube just moved in the vice. I'm going to mill two more sides, once along X and once along Y, and see how that looks.

[Spooq]

I really cranked down the vice this time and it has made all the difference!

[tbaker2500]

Well that's easier! Glad to hear it.

[Steve Seebold]

Don't move the table if you're checking the tram of the head. Move the spindle to a spot approximately in the center of the table on the "Y" axis. Put a indicator in the spindle. Run the "Z" axis dorn until you get a zero in you indicator and then rotate the spindle by hand.

If you move the X or Y axis, that won't tell you anything.

[bevinp]

If you move the X or Y axis, that won't tell you anything.

Steve,
Indicating on the table surface and moving the X or Y axis should reveal if the table surface is not parallel to the table dovetail surfaces. Unless I have misunderstood what you meant.
Bevin

[Steve Seebold]

Steve,
Indicating on the table surface and moving the X or Y axis should reveal if the table surface is not parallel to the table dovetail surfaces. Unless I have misunderstood what you meant.
Bevin

It will tell you if the X and Y are parallel to the ways, but it won't tell you if the Z axis is perpendicular to the X and Y axis.