Sieg X3 spindle problem (?)

[kevin.doherty]

I picked up a Grizzly G0463 recently, and I have what seems to be excessive play in the spindle.

I noted the problem while plunge cutting an array of holes in 0.080" aluminum; the 1/8" center-cutting end mill would walk around on the surface before starting the cut.

If I push sideways on the spindle with my hand (not too hard), I can see it move relative to the quill; a dial indicator shows 15 thousandths of motion with hand pressure.

My guess is that the bearing at the quill/spindle interface needs to be loaded, but there are no indications as to how to do that.

The manual is little help; it's a couple of years old, and the exploded parts diagram has numerous differences from the current machine.

There was at least one previous thread from a couple of years back discussing this problem, but there was no resolution posted.

So - anyone else have this problem? Any advice on how to tighten up the bearings?

Thanks -

Kevin Doherty

[cm3d]

If this is like other machines, there are two bearings near the bottom of the spindle separated by two spacers.

The spacers should be the same thickness, and there should be a nut putting pressure on the center of the top bearing. (the bearings should be in 'DB' configuration. (Back to Back) If you had them off, you should be able to hold the center races together, turn the outer race and both outer races should turn.


Now, the 1st troubleshooting question I have - did you have the base holding your indicator on the spindle housing, or on the table? You may have a loose gib that may only need a little adjustment. What you are interested in finding for certain is what is actually moving. You can get a little deflection in a tool if you are far enough from the spindle nose.

Craig

[kevin.doherty]

I admit the indicator base was on the table - but I was reading 15 mils deflection on the spindle, and only 3 mils on the quill (same setup).

Z gibs do have some play, which may account for the quill movement. But I can SEE the spindle move relative to the quill; no doubt about it.

The measurements were made w/o a tool in the spindle, as close to the boundary between the quill and the spindle as possible.

Re: the adjustment - I'm trying to find how to disassemble the quill/spindle assembly. Looking at the exploded view, it shows two M5 capscrews holding things together - but I don't seem to have 'em on my mill.

TNX -

Kevin

[cm3d]

Well, Kevin

I just went to the syilamerica.com site - no mechanical drawings for the machine.

So, if this were my machine, it would be my 1st step to examine any drawings that came with the machine to see how it come apart. I think, based on their use of a R8 Spindle taper, that it is similar to the quill on a Bridgport mill. There they had a single screw at the back of the nose of the spindle/bearing cap that need to be removed so we could use a spanner to unscrew the cap.

The pictures on the web are not clear about assembly/construction. There may be screws on the face of the spindle cap holding it up, or you may, like a Bridgeport, have to move the quill down a 1/2" to see a setscrew that needs to be removed to unscrew the nose piece.

So, assuming that this is a quill similar to a bridgeport machine, you can pull the spindle out from the nose end of the spindle. First move the machine to the highest Z travel. There may be screws holding the endcap on. Before you take them out, put something thick and soft on the table in case the spindle drops out easily / unexpectedly. IF there are screws on the endcap - remove them - carefully on the last one - it may drop. Then remove it.

On a bridgeport, we would sometimes have to tap on the top of the spindle shaft to get it to drop.. see if there is access to do that - but prepare for that before removing the cap.

At that point, IF this works like it seems from their online pictures, you should be able to remove the spindle and check for loosness in the bearings or bearing nut.

If it is like a Bridgeport, you would be able to get bearings from any local bearing suppy company if you determine the bearings are bad.

[cm3d]

Kevin,

Another thought - make sure the tool / collet is in the taper properly - the collet should slide up into the taper (without the tool in it) easily. It should not bottom out before the taper is fully engaged.

Look with a flashlight up into the taper and make sure there isn't anything that should not be there on the spindle taper. (Chips, Dirt, Whatever) It should be clean.

Later,
Craig

[BrendaEM]

If you do need to tear down your machine, this might be worth looking at : )

www.brendamake.com/temp/x3_prep_guide_aut.pdf

(Big PDF's are better download than read.)

[MIKE JEFFERS]

mine did this
you need to tighten the spindle bearings......however, a common fault
is that the diameter the (top)taper roller bearing sildes down ,per-loading
the spindle is too big ,only a couple of thou mind ,so remove the spindle
(see arcurotrade.co.uk for a breakdown manual) and machine or polish
the shaft so the bearing fits.
this was my experience your problem may be different but sounds the same
mike

[kevin.doherty]

Brenda, Mike -

Excellent reference! Thanks; better than an exploded parts diagram any day.

I've actually completed most of the turn-up, but I didn't disassemble the head because of the poor documentation. (I was afraid I wouldn't get it back together!)

I'll follow the teardown instructions and post with what I find.

Thanks all -

Kevin

[BrendaEM]

Someone else found the pdf in this thread:
http://www.cnczone.com/forums/showthread.php?t=34377

I would scribe or stamp witness marks on the side plates so the rear strap, so plates are assembled the same way it came from the factory. The alignment pin locations might be unique.

Lastly, I think a brass hammer would be better for tapping finely machined parts than a steel one : )

Otherwise the .pdf looks like excellent resource.

[kevin.doherty]

It turns out the keeper nut for the bearing retainer nut had worked loose; the bearing retainer was slowly un-screwing, and the spindle was dropping as it did so.

However - now that I have the spindle out, its condition is an absolute disgrace. The 'grease' - it looks like vaseline, but there's so little it's hard to say - is loaded with small metal fragments and casting sand.

If this is at all typical, anyone with an X3 needs to clean it out and regrease before use.