Dumb question on R8 (i think) spindle

My opinion is that the spindle the spindle is not bored deep enough to the diameter of the R8 collet shank.
Based on the photo of the test plug I don't think it's burrs that are preventing full insertion. It's simply not the correct diameter, deep enough to take the collet.

Did the mill come with the collets that don't fit or are those new?
 
I have several bearing pullers and a hydr press these come off the long end and Ive been having a hard time setting up to get them off
 
Just to clarify, I realize your wanting to recut the upper portion. Not the taper.

The upper portion is a precision bearing surface as well. It needs to be cut concentric and co-axial to the spindle taper.

Ideally, to no more that a ten thousandth. Your spindle should be at least as accurate as the bearings.
 
r-mm said:
I have several bearing pullers and a hydr press these come off the long end and Ive been having a hard time setting up to get them off
Click to expand...


Bearings can be a pain to remove on long spindles.

Most like yours, I've removed by having a helper hold the spindle upside down on an aluminum block, and using a section of pvc pipe over the spindle nose, against the outer race. Hammering it off with a mallet.

I don't reuse bearings after removal. Replacements are cheap and plentiful.

I've been using the same thick walled PVC pipe sections for 10 years. About 4$ ea at ace hardware.

If you take the spindle and quill sleeve with you to the hardware store, it's easy to find some pvc sections of the appropriate diameter for reinstalling new bearings. Just put all the forces on the inner race for shafts, and the outer race for bores. Don't transfer forces through the rolling elements to avoid the risk if brinelling.
 
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Appreciate all that advice. This is my first mill and I don't mind a little work to see if the spindle is salvageable. Chances are I may get some better collets and end mills once I get the hang of things so I view this as semi-sacrificial startup stuff. I ordered a larger tool holder and will get a 5/8 carbide boring bar and see if I can clean the inside on the lathe, with the bearings removed.

A question regarding hardening - how deep into the metal does it go? I already removed the ugliest high spots with the alum oxide flap disc. Is the metal hard "all the way down" ?
 
You should really do this on the mill. Make a block for your boring bar. Put it in the vise straight up and have at it. You can set your depth with the quill lock.
Just an idea.
 
ummm.... about that mill.... and its lack of... spindle?
 
It is most likely made from a pre hardened steel. So, it would be through hardened.

A spindle would be hardened first, and ground after, to minimize the effects of the heat treat causing dimensional changes.

I doubt that is an extremely hard steel, but tough and hard nonetheless. Take light cuts with sharp insert and you'll probably be fine. Maybe something like a tcgt non-ferous style insert. They are very sharp and make light cuts at low speeds a breeze.
 
r-mm said:
ummm.... about that mill.... and its lack of... spindle?
Click to expand...

It's really using the mill like a lathe and turning the ID of the mill spindle in place.
You reinstall the spindle, spin the work-piece (the spindle) and move the tool with the table X or Y-axis lead screws.
The boring bar is held in a block that is bolted to the table and is pointing straight up inside the spindle.

-brino
 
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