Mill Spindle Cleanup

[Madpiper]

Hi,

I have my RF45 clone apart currently, and thought it might be a good time to address the interior of the R8 spindle; there’s some markings and rough spots on the interior.
What are some options for cleaning this up? (Have a small video, but can’t seem to post).
Thanks.

 

[PeterT]

Hopefully one of the forum admins will respond. I'm not sure if video format files are allowed and/or associated file size limits. Some guys have uploaded their videos to storage areas & inserted links, but I'm not up to speed on good sites. Failing that, pictures?

 

[Tom O]

Would it be possible to take a screenshot while the video is playing or is on pause?

 

[Madpiper]

I’ll get a picture or two of the defect once I’m home tomorrow. Looks like the ideal fix is to put in a lathe, and have the inside ground; anyone have a Toolpost grinder?

 

[Susquatch]

Hopefully one of the forum admins will respond. I'm not sure if video format files are allowed and/or associated file size limits.

At this time, we cannot host videos due to the size requirements.

 

[Madpiper]

 

[djberta]

Is that damage from the collets or holders rotating under load?

 

[Madpiper]

Is that damage from the collets or holders rotating under load?

I assume that’s the cause? Now that it’s out, I can replace the pin so this mess doesn’t happen again.

 

[whydontu]

I’ve fixed these by careful filing off the projecting bits and then cautious application of a cylinder reamer. All you want to do is knock off the torn up stuff without altering the taper.

 

[Susquatch]

Now that it’s out, I can replace the pin so this mess doesn’t happen again.

The pin isn't supposed to stop this from happening. It will take a little load but it's really only there to stop the arbour from turning while it's being tightened. The taper itself holds the collet under load.

Usually this happens because the drawbar isn't tightened enough or because of dirt or swarf that gets in there. There are some really good discussions on this issue elsewhere in the forum.

 

[Madpiper]

I’ve fixed these by careful filing off the projecting bits and then cautious application of a cylinder reamer. All you want to do is knock off the torn up stuff without altering the taper.

View attachment 61048

Great idea on the reamer; I was trying to think of solutions other than grinding. Thanks.

 

[Madpiper]

The pin isn't supposed to stop this from happening. It will take a little load but it's really only there to stop the arbour from turning while it's being tightened. The taper itself holds the collet under load.

Usually this happens because the drawbar isn't tightened enough or because of dirt or swarf that gets in there. There are some really good discussions on this issue elsewhere in the forum.

Agreed, the purpose of the pin is for alignment, and not ment to be under tension. I think the problem also starts to snowball with damage to the spindle; rougher surface-less holding capacity-loose tool adds more damage- shears pin, etc.

 

[Mcgyver]

That is a mess, and it doesn't look hardened? That doesn't seem right, but if hardened I wouldn't think it would score like that. One thing you can do is, with the machine back together, using a sine bar, set the head very accurately to the taper angle. With a point in one of those pencil air grinders, dress the point, angle it slightly (you don't want the whole point in contact) then just kiss the taper with the mill running, grinder running, and moving the table up and down. Over and over until you spark out.