Z axis problems on X3

[Thorpydo]

Hey,

I have two problems with my Z axis and I figure its about time to address the issues.

#1: If a picture is a thousand words, then a video must be a million (Maybe only a couple thousand for this video due to quality) . . . Video attached. When I change direction, my Z gib noticeably moves up or down. I understand that the threaded insert is to tighten the gib, but in this case, the gib can still move. Over time, the gib worked itself much looser and I re tightened it. If I tighten it too much, then obviously the Z axis stalls. What am I doing wrong here?

YouTube - DSCN0123

YouTube - DSCN0123

#2: Jogging the axis slowly the machine sounds smooth. When I rapid, a wobbling, sorta of vibrating noise happens, not sure why. Can someone clue me in?

Thanks.

[caleb105]

Are you sure that the gib is facing the correct way? One side should have some small indents on it that allow the set screws to dig in, keeping the gib from slipping like it's doing on your machine.

-Caleb105-

[Greolt]

The gibb has a notch at the top end which the adjust screw sits in. But does have some slop.

On the bottom there is another screw which does not sit in a notch but a step.

Adjust with the top screw then nip up the bottom screw.

Having said that the gibbs on these Sieg machines can be abysmally poor.

I think the manufacturers think it is just a packer strip.

Mine had a 6 thou discrepancy. That is when snug at one end it had 6 thou slop at the other end.

Machined (roughly) at the wrong angle.

It will never adjust if like that and will exhibit the same symptoms as you describe.

Greg

[Thorpydo]

I'm not seeing this other screw. Do you mean that it is under the first screw or on the underside of the head?

I have access to a surface grinder at school. Would it be worth while to grind my gibs flat?

Last night I ran this part. . for fun, not fur use (First part on my high speed spindle, zinging along at 25 ipm, 7200rpm, .05 DOC with a .250 endmill). It's hard to see in the picture, but every time the machine moves the z up, after every face, chamfer and contour, the machine actually moves the Z axis down and few thou before it goes up. It's definitely due to this mechanical problem.

[Crevice Reamer]

The SX3 has a top and bottom screw. The X3 only has a top screw.

You should call Grizzly and have them send you a new gibb and screw under warranty.

1-800-523-4777

#P0463063= Gib Adjust Screw
#P0463064= Gib.

http://grizzly.com/images/manuals/g0463_m.pdf

CR.

[Greolt]

Originally Posted by Crevice Reamer The SX3 has a top and bottom screw. The X3 only has a top screw.

Ah I did not know that.

Greg

[dwessels]

Originally Posted by Thorpydo Last night I ran this part. . for fun, not fur use (First part on my high speed spindle, zinging along at 25 ipm, 7200rpm, .05 DOC with a .250 endmill).

Thorpydo,

I am interested in what you did to the high speed spindle... do you have any pics or information that you can share about it? I am trying to decide what to do to my X3 spindle.

Thanks,
Denzil

EDIT: Saw the other thread... thanks.

[MRM RCModels]

Originally Posted by Thorpydo I'm not seeing this other screw. Do you mean that it is under the first screw or on the underside of the head? I have access to a surface grinder at school. Would it be worth while to grind my gibs flat? Last night I ran this part. . for fun, not fur use (First part on my high speed spindle, zinging along at 25 ipm, 7200rpm, .05 DOC with a .250 endmill). It's hard to see in the picture, but every time the machine moves the z up, after every face, chamfer and contour, the machine actually moves the Z axis down and few thou before it goes up. It's definitely due to this mechanical problem.

The mill head will move down a few thou no matter what when changing direction. It's the inertia of the mill head coupled coupled with it's center mass being so far in front of the column. Does the same thing on mine. I compensate by having the tool change Z axis off the part whenever possible.

[Thorpydo]

The mill head will move down a few thou no matter what when changing direction. It's the inertia of the mill head coupled coupled with it's center mass being so far in front of the column. Does the same thing on mine. I compensate by having the tool change Z axis off the part whenever possible.

What if I put the acceleration rate quite a bit slower?

[MRM RCModels]

Originally Posted by Thorpydo What if I put the acceleration rate quite a bit slower?

That may help.

[JpBinc]

I have an X3 with a 2Hp VFD driven 3phase ac motor on it. ( in other words a lot of weight on the Z axis ) I got mine from grizzly also, and I do not see this problem. My adjustment screw has a two slots in it and the bottom slot works against the top slot to stop it from doing that. Does yours have two aslots in it. You can see the two slots in the picture in the parts manual noted above. I am sure you know what I am saying but maybe not so I thought I would put my two cents in.

[slashmaster]

How does the gib for the Z axis work anyway? Is the gib really a wedge and screwing it downwards tightens it?