Discussion on all milling machines vertical & horizontal, including but not limited to Bridgeports, Hardinge, South Bend, Clausing, Van Norman, including imports.
KellyJones wrote: ↑Mon Jun 14, 2021 11:06 am
Russell got it exactly right.The vise appears to be out in the Z axis, that is, parallelism to the table surface.
Kelly, am I thick, or do you mean that it's a perpendicularity problem? The Z axis is normally the quill/spindle----and I gather that the vise jaw isn't parallel when the spindle is dialed true to the table. Am I correct?
If so, I've talked about that problem previously. I sub-contracted a job where I had to square hundreds of 5/8" x 5/8" x approximately 1" long leaded brass blocks, which after being rough machined and squared were transformed in to read and write heads for IBM computers. This was long ago, in the late 60's, when NC's were used (not CNC's). I had to hold the blocks square within a half thou, and struggled endlessly with what was then a new Bridgeport vise. I switched to a Kurt and my problems ended 100%.
I now own two Kurt vises. I have little interest in anything else. They work, and they work well.
Just sayin'!
Disclaimer: I have no interest in the Kurt organization aside from being a very pleased user of their products.
H
Wise people talk because they have something to say. Fools talk because they have to say something.
shootnride wrote: ↑Mon Jun 14, 2021 6:17 pm
It seems that this issue could be resolved with some careful set-up by truing the vise base on a surface grinder.
Ted
This was the thought I had. Remove all jaws and measure the height of the vise ways on the surface plate. If they are at least parallel to each other in both axis, you could grind in the bottom. Would it be wrong to even consider fly cutting the bottom if a surface grinder was not available?
Standards are so important that everyone must have their own...
To measure is to know - Lord Kelvin
Disclaimer: I'm just a guy with a few machines...
KellyJones wrote: ↑Mon Jun 14, 2021 11:06 am
Russell got it exactly right.The vise appears to be out in the Z axis, that is, parallelism to the table surface.
Kelly, am I thick, or do you mean that it's a perpendicularity problem? The Z axis is normally the quill/spindle----and I gather that the vise jaw isn't parallel when the spindle is dialed true to the table. Am I correct?
I don't understand the reference to the Z axis, either. But Kelly's problem is that the bed of the vise (i.e. the surface on which you'd set parallels) isn't parallel to the base of the vise (i.e. the surface that rests on the mill table).
On a vertical mill, the axes that run parallel to the surface of the table are X an Y.
The z axis is the direction that is normal to the table ( 90 degree angle from the table)
The surfaces that you are speaking about are XY planes that are offset from the table in the Z axis direction.
If I am understanding this correctly, the vise Y axis has tilt in the +/- Z axis direction.
It seems to me that this is corrected with head "Nod" adjustment???
kl7sg wrote: ↑Fri Jun 18, 2021 9:44 am
If I am understanding this correctly, the vise Y axis has tilt in the +/- Z axis direction.
It seems to me that this is corrected with head "Nod" adjustment???
Then the spindle axis will be neither parallel to the column nor perpendicular to the table.
kl7sg wrote: ↑Fri Jun 18, 2021 9:38 am
On a vertical mill, the axes that run parallel to the surface of the table are X an Y.
The z axis is the direction that is normal to the table ( 90 degree angle from the table)
The surfaces that you are speaking about are XY planes that are offset from the table in the Z axis direction.
is the same on a horizontal mill....
Generally, Z follows the milling tool axis....on a machine that is primarily a mill.
is a different critter if the machine is primarily a lathe.
Ok, I have a clear image now. It can be described two ways, one being perpendicularity to the X-Y axes, the other as parallelism to the theoretical Z axis. It can manifest as an error in the true Z axis, with error front to back, side to side, or a combination of the two. The side to side error could be corrected by altering the base. The front to back error, not so much.
I agree with shootnride. The vise can be corrected by a careful setup such that the ways of the vise are dead parallel to the table of the mill or surface grinder. The base would then be machined (fly cutter) or ground. That will correct any parallelism problems the vise may have, but it does NOT address any possible deviation from perpendicularity in the fixed jaw as it relates to the Y axis. If there is error in that axis, the fixed jaw would then require correction.
H
Wise people talk because they have something to say. Fools talk because they have to say something.
But, the correction would require two things.
1) correct the error in the vise fixed jaw.
2) adjust for the y axis tilt with by changing the height of the vise fixed jaw parallel (if used)
If not, when tightened, you run the risk of the work piece following the tilted vise way.