Flycutter and 0.40mm TiR?

[jdm23]

I have just started with milling on my combo machine. Trying to clean a bit a piece of structural steel (I know is one of worst materials ever, but I have nothing else easily available), not knowing jack about the ideal shape I've just ground some back relief in an 8mm square HSS.

The result is less than perfect, I used a slow power feed, but something must have moved at some point

Probably it has nothing to do with the above but it bothers me that I can see the top of the spindle wobble a bit, in fact I measured as per topic title, where the picture is taken. In another topic I had reported about a slightly better TiR measured at the collet chuck and was told that the machine is useable anyway.

This is a 550W machine with a MT2 spindle. Any chance that the bearings can be adjusted? Replacing them could improve the situation?

 

[DavidR8]

Oops looks like a couple of your pics didn't load correctly.

 

[jdm23]

Oops looks like a couple of your pics didn't load correctly.

Thanks, should be fixed now.

 

[pacifica]

I have just started with milling on my combo machine. Trying to clean a bit a piece of structural steel (I know is one of worst materials ever, but I have nothing else easily available), not knowing jack about the ideal shape I've just ground some back relief in an 8mm square HSS.

The result is less than perfect, I used a slow power feed, but something must have moved at some point

View attachment 359748

Probably it has nothing to do with the above but it bothers me that I can see the top of the spindle wobble a bit, in fact I measured as per topic title, where the picture is taken. In another topic I had reported about a slightly better TiR measured at the collet chuck and was told that the machine is useable anyway.

View attachment 359747
This is a 550W machine with a MT2 spindle. Any chance that the bearings can be adjusted? Replacing them could improve the situation?

Is spindle holding flycutter tight?

 

[Aukai]

The draw bar shaft on top will wobble, indicate at the spindle, chuck/arbor, and tooling.

 

[jdm23]

The draw bar shaft on top will wobble, indicate at the spindle, chuck/arbor, and tooling.

I am not about the draw bar. There is 0.40mm TiR on the spindle just below the wrench cut.

 

[Aukai]

What is it at the working end of the spindle?

 

[jdm23]

What is it at the working end of the spindle?

Better than that, but I don't think that is normal.
So my question again:

Any chance that the bearings can be adjusted? Replacing them could improve the situation?

 

[WCraig]

0.4 mm is about 0.016 inches. That is far, far too much runout for a mill spindle. Can you take a picture of how you measured this? If you hold something that is known to be straight (say drill rod; aka silver steel), does the measured runout get worse further away from the spindle?

Is your combo machine new? If so, contact the dealer. If used, what do you know about the history? A morse taper 2 spindle isn't very heavy duty so it is possible that the spindle got bent during a crash.

Craig

 

[markba633csi]

If the bearings are the tapered roller type then they should be adjustable. If they are ball bearings then usually not.
Does this machine have a quill like a drill press? If so you would want to lock it down before testing for runout, and during most milling operations
The milling you did on the square piece of tubing in post #1 looks reasonable as far as the scalloping pattern you would expect. Clamping hollow material can be dangerous though, be careful. Pieces can pull out and launch themselves suddenly in any direction, with bad results. This is especially true when drilling large holes, as the drill bit breaks thru. Passing a piece of bar stock or even lumber thru the part being machined, with both ends of the bar stock fastened to the table is recommended, in addition to the vise. Yes it's more hassle but better than getting hurt.
Spindle runout should be much less than one thousandth of an inch with good bearings FYI
-Mark