[Rockyr49]

I understand that you may be in a situation where nobody in yur area can regrind this thing for you. That video makes it look easy. But from years of experience, I can tell you that it is not. The taper in the video is a 40 yours is a 4mt. Little or no room for error on yours. If you must try it, PLEASE,PLEASE, PLEASE, make sure the grinder is parallel with the centerline of the spindle. Any deviation from that and you have a junk spindle when you are done. Any backlash in the axis will cause the angle to be wrong. The taper will only be as good as the machine is. And in your case the machine does not sound too good. If you must, you must. But again regrinding tapers in the machine is all that I have done for over 15 years. I've done over 4000 tapers and would never consider doing any taper by programming the the machine. Way too much room for error.
Good luck to you.
Rocky

www.spindlegrinding.com

[[email protected]]

Rocky,
You posted what I tried to post yesterday. I typed for 20 minutes, touched the wrong button and I have no idea where it went.
Boy it was a good account of what can go wrong with the set up outlined in the
pictures. To bad we can't get more people to call us and have there spindles reground.
If I thought a grinder mounted on the table was the answer, that is what I would
done back in 1982. Instead, I built a portable grinder, packed it in containers (3)
loaded them in my 1979 station wagon and started to grind spindles.
As we have discussed many many times, mounting the grinder on the machine and using the axis movement to move the grinder opens the door for too many variables.
I like the way we do it because it works and we prove it about three or four times a day. If it didn't work, companies would not call us back again and again.
Welcome back, how was your vacation?
Regards Walt.......

[WhiteTiger]

The whole point is sort of moot since he disassembled the thing and found a bearing journal "knurled" with a centerpunch (post #15). With that sort of condition there's no way that in situ dressing with the spindle running could produce an improvement over the original.

Even the simplest alternative of mounting a morse taper dressing reamer perpendicular to the table and easing the spindle onto it at low speed wouldn't do any good with the bearings that sloppy, imo anyway.


Tiger

[HuFlungDung]

I agree Tiger. I'd still attempt a home shop repair the way it was outlined by the guy in post #8

[WhiteTiger]

I dunno... that guy seems a bit shifty (that one was too obvious to pass up)


Tiger

[One of Many]

Little or no room for error on yours. If you must try it, PLEASE,PLEASE, PLEASE, make sure the grinder is parallel with the centerline of the spindle. Any deviation from that and you have a junk spindle when you are done. Any backlash in the axis will cause the angle to be wrong. The taper will only be as good as the machine is. And in your case the machine does not sound too good.

Rockywww.spindlegrinding.com

To clarify this point somewhat. The spindle of the grinder centerline needs to grind on the spindle tapers quadrant that is parallel to the mill spindle center in one plane and follow the taper in another plane.

In other words. Using the Z only as theory. If the spindle centerline on the mill is not perfectly parallel to the axis it being ground with. The stone will grind a convex or concave surface in the taper by cutting at the slightest angle to the travel plane. Basically visualize a straight line on the surface of a cone at an angle to the cones centerline. That becomes an arch on the taper surface with a straight edge parallel to the center line.

I gather that Rocky's equipment takes this out of the picture by having their own axis that can be proven parallel and on center?

DC

[Rockyr49]

You've got it. a lot of trial and error by the boss and we can now do it quicker and for the most part cheaper than pulling the spindle. It's not the cost of the spindle as much as the cost of the downtime involved in reapir or replacement.

[Ch_Irawan]

Is this CNC that you could do an X,Z move?

Yes, I am doing CNC retrofitting.

No matter if not.......If the head tilts right and left, you could tilt the head to indicate zero off the taper, then just do a Z move on the column.

I like the idea, but difficulties are still on alignment I think.

Also, are you certain it needs a grinder? Do you know specifically that its too hard for carbide?

Not sure, just thinking that the grinding will give the right surface finish.

well you found his....and he probably found yours.....

I doubt that he found mine first, my first post is just about two weeks ago.

The whole point is sort of moot since he disassembled the thing and found a bearing journal "knurled" with a centerpunch

Yes, need to work with the journal first.

I'd still attempt a home shop repair the way it was outlined by the guy in post #8

Your suggestion is on my consideration, but again I have to check the quality of my lathe first...

It was my blindness driving me to write here, I said that I am not a good machinist as I am better in soldering and coding. I want to learn.

I have to thank to all here and forgive me for my ignorance that I am still thinking to do it someday, the spindle is already a junk for sure. Currently I am quiet busy with the new machine, and in the meantime I will try to learn more about grinding process.

Regards, CI.