Tramming vise on mill

[Investigator]

Just want to make sure I understand......
This is in reference to a RF30 type round column mill:

After I fit the vise to the mill and get it trammed, if I raise the head I dont have to re-tram the vise right? The jaws will still be perpendicular to the spindle even if the spindle has moved up and possibly over a bit. Not talking about tool changes, but between parts.

For example, Say I have the vise trammed in and all is good. I make a part and move on to another project. Some time later I have a new project and new part to make. I realize I dont have enough spindle height for the new part so I raise the head. Now I have enough spindle height and put the part in the vise. At this point is the vise still trammed correctly even though the head moved up (increase in z axis) and possibly moved to the side a bit?

 

[mikey]

Just leave the vise alone and bump the head to align it to the vise, then tighten and check. You may have to do this a few times because locking the screws that tighten the head to the column can move the head a tiny bit. It's a hassle but you get used to it quickly.

 

[T Bredehoft]

You are correct. the relationship between the vice and the table doesn't change when you move the head. Just don't asume that X and Y zero will be the same after you move the head.

 

[Silverbullet]

Wouldn't a laser pointer mounted on the head be able to relocate the head back to the same spot within a few thousandth. Or two to intersect on one Spot.

 

[T Bredehoft]

a laser pointer

I tried that with mine, 15 feet away the laser dot is about 3/16 inch and fuzzy. Is there a more precise laser available? I tried both a freehand pointer and a commercial (but cheap) level with a built in laser.

 

[kd4gij]

Wouldn't a laser pointer mounted on the head be able to relocate the head back to the same spot within a few thousandth. Or two to intersect on one Spot.

I read a thread on another board where a guy drew a thin vertical line on a wall and used a laser mounted on the head just for that.

 

[kd4gij]

I tried that with mine, 15 feet away the laser dot is about 3/16 inch and fuzzy. Is there a more precise laser available? I tried both a freehand pointer and a commercial (but cheap) level with a built in laser.

Yes but there not cheap.

 

[Silverbullet]

Couldn't it be pointed at the base of the mill and it work the same . I would think it would be more accurate using the permanent base then a wall or ceiling. Even turned if it's lined up on the same spot.

 

[Bob Korves]

3/16" over 15' is a quite small angle, .19 degree if the dot is off by one entire 3/16" diameter, which is unlikely. That works for repeatably squaring round mill heads to the table. Over the distance from head to table, 3/16" is a much larger error. Those machines often have errors with the Z axis being not perpendicular to the X and Y axes such that real accuracy will not be attainable without resetting the column of the machine so the travel of the head is in a line perpendicular to the table axes. Even then, the quill travel axis may not match the Z axis of the head travel. Those machines can be made quite accurate, but it takes some understanding of what causes the errors, then reading them, and then fixing them in a proper sequence to make comprehensive progress. Lacking that, the errors just get chased to another axis.

 

[kd4gij]

The best setup I have seen was the guy used 2 1" linear rails 1 on either side of the head with 2" long bearings.