First cut from my 8520...what is this god awful noise coming from...

[zakruvalcaba]

That looks like a strong repair- stronger than epoxy I'm sure

More than likely overkill and ruined an OEM part but at least it's not going to move....

 

[markba633csi]

LOL sometimes OEM can stand some improvement; ask anyone with an Italian car

 

[wa5cab]

I think that instead of hitting it with a file, I would either mount it in a chuck or on an expanding mandrel and face it back square to either the OD or the ID (whichever is important).

 

[zakruvalcaba]

Thanks everyone for helping me identify my problem. I have the newly welded plate/collar on, new bearings in my pulley, and everything back together. Runs very smoothly now. I haven't made any cuts yet but I'm hopeful that the welded plate / collar fixed everything. During my fix I even managed to source a complete replacement head assembly complete with all new bearings, oilers, everything!

My next question is in regards to my collet holder. I went to take it off for the first time during this process and it was damn near impossible to remove. I fought with this thing for at least an hour before I finally got it free. Something's not right. Look at the video below and tell me if my collet is seating properly. It looks like it's getting caught in the taper and really locking and ultimately freezing into place. Am I wrong?

Again, thanks for everyone's help.

 

[Briney Eye]

You have the spindle cap nut and drawbar that require two wrenches in opposition (in the absence of a spindle brake), I believe. Is that how you were trying to do it? I have to whack my drawbar with a brass hammer to drive the collet out. A deadblow hammer also works, but not nearly as well. Since there's a shoulder on your drawbar underneath the cap nut, simply threading the drawbar out pushes the collet out of the taper.

-Jon

 

[zakruvalcaba]

You have the spindle cap nut and drawbar that require two wrenches in opposition (in the absence of a spindle brake), I believe. Is that how you were trying to do it? I have to whack my drawbar with a brass hammer to drive the collet out. A deadblow hammer also works, but not nearly as well. Since there's a shoulder on your drawbar underneath the cap nut, simply threading the drawbar out pushes the collet out of the taper.

-Jon

Let me take a picture and post what I have Jon. This set up is definitely different than the other head I just received. I think the problem last time is that I used an adjustable wrench to tighten the drawbar and that brought the collet holder into the taper so much that it was REALLY difficult to get out. I suspect that I'm supposed to hand tighten the drawbar and then hand tighten the cap nut to secure it to a point where it's easier to get out...

 

[Meta Key]

My 8520 came to me with a little tiny wrench that I use to adjust/manipulate the drawbar. I don't know if it was original with the machine or not -- I am the second owner. I *assumed* it was original and was small in order to limit the amount of torque one could apply. Here's a pic of the wrench:


Also, to loosen the tool holder I also whack the top of the drawbar with a brass hammer. It doesn't take much of a whack, just enough to shake things loose. Then, I hold the tool and unscrew the drawbar with the tiny wrench til the tool drops out..


Meta Key

 

[zakruvalcaba]

My 8520 came to me with a little tiny wrench that I use to adjust/manipulate the drawbar. I don't know if it was original with the machine or not -- I am the second owner. I *assumed* it was original and was small in order to limit the amount of torque one could apply. Here's a pic of the wrench:
View attachment 271941

Also, to loosen the tool holder I also whack the top of the drawbar with a brass hammer. It doesn't take much of a whack, just enough to shake things loose. Then, I hold the tool and unscrew the drawbar with the tiny wrench til the tool drops out..
View attachment 271942

Meta Key

Yeah I have the same drawbar and spindle as you. Mine took a significant amount of force to remove. The drawbar came right off and out but the collet holder was stuck, almost seized, in the spindle. Can I see how your collet fits into your spindle? Here are the 2 drawbars / spindles I own. The one that looks like yours is the one currently installed in my mill. Mine however, did not come with the small wrench.

 

[Meta Key]

Sure -- but first a word about removing a collet or end mill holder:

1) Engage the brake.
2) With the tiny wrench, unscrew the drawbar as far as possible. If the toolholder was properly engaged, this is typically 1/3 to 1/2 turn. This has the effect of removing upward pressure on the toolholder threads and placing downward pressure on the toolholder threads.
3) While holding the tool in one hand give a good, quick rap on the drawbar with a brass hammer. You will feel when the toolholder breaks free from the spindle; you'll be able to wiggle or shake it a small amount.
4) While continuing to hold the tool use the tiny wrench to fully unscrew the drawbar. Toolholder and tool assembly will drop into your hand.

The first two steps seem crucial to me. Without the initial un-threading movement of the drawbar, banging on the thing is probably ineffective.

I'm not entirely sure what you mean about "the drawbar came right off and out" so if I mis-interpreted that remark the following does not apply: Do not remove the drawbar. Un-thread it a small amount, 1/2 turn is plenty. Then, rap on it with your brass hammer. Then, un-thread it far enough to allow the toolholder to fall out of the spindle. Sorry, if I misunderstood...

Here's a picture of a collet (with an edge finder in it) fully engaged in the spindle:


Meta Key

 

[Meta Key]

Oh, and BTW, in the 20 years I've owned and used this mill I have never removed the cap nut. The little wrench fits fine without removing the cap nut.

Meta Key