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



## zakruvalcaba (Jun 19, 2018)

My 8520 came home this weekend. Couldn't be more excited. There's some minor work to do on it still but it's in great shape. Just started my first cut and I'm getting this terrible noise. It's so loud...to the point where I may need hearing protection. I'm using a 1/4" HSS  endmill cutting about 1/8" down onto aluminum. Speed is at 1900 RPM. It seems that the faster I move on the X the noise lessens but this can't be normal....


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## markba633csi (Jun 19, 2018)

Are you sure the spindle is turning in the correct direction?
Have you tried slower speeds?
Are you only getting the noise when cutting (nothing near the motor pulleys rubbing against the covers)?
Mark
ps Looks like you are using a collet chuck to hold the endmill- is it firmly held in the spindle- no looseness


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## RandyM (Jun 19, 2018)

I would first stop the rattle of the lever on the upper left hand side of the machine and then stop any others.


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## zakruvalcaba (Jun 19, 2018)

Thanks for the quick reply Mark. I have the lever in the "Forward" position and have verified that the cutter is moving clockwise.
I have not tried slower speeds yet. I was cutting aluminum just fine with no ridiculous noises like this on my Rong Fu at 2000 RPM.
As you can hear in the video, there is no noise at first and only comes when I actually touch the work piece.


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## zakruvalcaba (Jun 19, 2018)

RandyM said:


> I would first stop the rattle of the lever on the upper left hand side of the machine and then stop any others.



This noise is REALLY loud. Very unpleasant. The brake has nothing to do with this noise...but yeah I noticed it flopping around after I looked at the video a few times. Need to figure out how to tighten it.


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## zakruvalcaba (Jun 19, 2018)

markba633csi said:


> ps Looks like you are using a collet chuck to hold the endmill- is it firmly held in the spindle- no looseness



I mean I'm no expert by any means but if I hold a crescent wrench at the top and attempt to tighten the chuck...it doesn't move at all.


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## zakruvalcaba (Jun 19, 2018)

A couple more videos of the mill on before touching work piece and after touching work piece. Also, check out second video...just discovered this. I would imagine that the pulley should be secured and not be able to move up and down like that? Haha.


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## RandyM (Jun 19, 2018)

The work piece and vice are not vibrating? The Quill and table locks are locked? You have a vibration and you'll just have to keep checking them all out. And, it may be a combination of several. Good luck.


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## Briney Eye (Jun 19, 2018)

zakruvalcaba said:


> My 8520 came home this weekend. Couldn't be more excited. There's some minor work to do on it still but it's in great shape. Just started my first cut and I'm getting this terrible noise. It's so loud...to the point where I may need hearing protection. I'm using a 1/4" HSS  endmill cutting about 1/8" down onto aluminum. Speed is at 1900 RPM. It seems that the faster I move on the X the noise lessens but this can't be normal....



You see the brake handle shaking in sync with the noise?  The brake ring is bouncing against the inside of the pulley.  It's probably broken, like mine was.  I silver brazed the ductile iron ring back together, shimmed it to fit closely around the head, bored and sleeved the worn pulley back into close tolerance, and mine only occasionally rubs now.  Not the best design, though.  If the ring breaks again (and it probably will) I figure I'll make a new one that fits better.


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## Briney Eye (Jun 19, 2018)

zakruvalcaba said:


> A couple more videos of the mill on before touching work piece and after touching work piece. Also, check out second video...just discovered this. I would imagine that the pulley should be secured and not be able to move up and down like that? Haha.



You're missing a retaining clip.  Do you have the exploded diagram of the head assembly?  Go to vintagemachinery and download the manual.


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## benmychree (Jun 19, 2018)

Also, you have that end mill hanging way to far out of the collet; it may be better to use end mill holders that fit directly in the spindle.


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## markba633csi (Jun 19, 2018)

Agree with John, whatever else may be wrong, that endmill/toolholding arrangement is hanging too far out


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## Briney Eye (Jun 19, 2018)

Briney Eye said:


> You're missing a retaining clip.  Do you have the exploded diagram of the head assembly?  Go to vintagemachinery and download the manual.



I thought of something else.  Have you adjusted the play in the quill?  I still think it's the brake ring rattling against the inside of the pulley, but if things are loosey-goosey in the top of the head that will amplify the problem.  Make sure that the pulley sleeve is tightened down to the top of the head, the bearing retaining clips are properly installed, and that the spline follower plate is tight on the top of the pulley.  There are also a couple of spring-loaded "plugs" (557-007) in the plate (556-020) that grip the splined spindle shaft, keep it from rattling, and also keep the quill where you put it when they're properly adjusted.  Check for play in all of the bearings, too.  I was fortunate and the quill bearings in mine were still good, but I replaced all of the other bearings anyway.  They're cheap, and I figured that since I already had it apart I might as well install new ones.


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## dlane (Jun 19, 2018)

Post 7 the end mill looks crooked when zoomed in, is the collet snapped into the nut before installing onto the chuck ,
Just looks funny. 
Edit  are you sure it’s turning cw looks ccw when stoping. Sounds like a train whistle,May be a optical thing


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## zakruvalcaba (Jun 19, 2018)

markba633csi said:


> Agree with John, whatever else may be wrong, that endmill/toolholding arrangement is hanging too far out



Thanks for the tip. My work piece (which is not shown in the video) requires a depth of cut of 1.500" which is why my end mill sticks out so far. There's an additional .500 of clearance required for a jig so the end mill length needs to total 2.000". Not making excuses, it's just I need the length.


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## zakruvalcaba (Jun 19, 2018)

dlane said:


> Post 7 the end mill looks crooked when zoomed in, is the collet snapped into the nut before installing onto the chuck ,
> Just looks funny.
> Edit  are you sure it’s turning cw looks ccw when stoping. Sounds like a train whistle,May be a optical thing



Yes, it's snapped in and yes, I'm 100% positive that it's turning cw.


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## zakruvalcaba (Jun 19, 2018)

Briney Eye said:


> You see the brake handle shaking in sync with the noise?  The brake ring is bouncing against the inside of the pulley.  It's probably broken, like mine was.  I silver brazed the ductile iron ring back together, shimmed it to fit closely around the head, bored and sleeved the worn pulley back into close tolerance, and mine only occasionally rubs now.  Not the best design, though.  If the ring breaks again (and it probably will) I figure I'll make a new one that fits better.



I'm pretty sure it's not the brake. I held it firmly with my left hand and manipulated the X with my right hand and the noise was still there.


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## zakruvalcaba (Jun 19, 2018)

I reduced my speed from 1900 to 600 and the noise has SIGNIFICANTLY reduced....almost non-existent. At this point, I'm guessing it's the pulley rattling at higher speeds since it's not secured correctly?


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## zakruvalcaba (Jun 19, 2018)

Briney Eye said:


> I thought of something else.  Have you adjusted the play in the quill?  I still think it's the brake ring rattling against the inside of the pulley, but if things are loosey-goosey in the top of the head that will amplify the problem.  Make sure that the pulley sleeve is tightened down to the top of the head, the bearing retaining clips are properly installed, and that the spline follower plate is tight on the top of the pulley.  There are also a couple of spring-loaded "plugs" (557-007) in the plate (556-020) that grip the splined spindle shaft, keep it from rattling, and also keep the quill where you put it when they're properly adjusted.  Check for play in all of the bearings, too.  I was fortunate and the quill bearings in mine were still good, but I replaced all of the other bearings anyway.  They're cheap, and I figured that since I already had it apart I might as well install new ones.



I'll take this thing apart when I have some free time. This is the worst part of the year for me with kids being home, vacations, work, etc. but I'll get to it. Thanks for the reply. These retaining clips are standard I take it...


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## Briney Eye (Jun 20, 2018)

zakruvalcaba said:


> I'll take this thing apart when I have some free time. This is the worst part of the year for me with kids being home, vacations, work, etc. but I'll get to it. Thanks for the reply. These retaining clips are standard I take it...



My kids are long gone and I still don't seem to have enough time .

Like I said, download the manual from Vintage Machinery and check out the head assembly diagram.  There might not be any screws in the 990-061 Pulley Sleeve Assembly, in which case you will need three #10-24 x 1/2 socket head cap screws.  If they are (heaven forbid!) broken, your life just got a lot more interesting all of a sudden.  If the pulley sleeve is loose it would explain the racket.  Since there is a little radial slop in the assembly I shimmed the gap around the spline shaft to make sure it was centered before tightening the screws (and used Loc-Tite).


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## markba633csi (Jun 20, 2018)

Someone had a procedure on rebuilding the head- if I can find the link I'll post it here
Mark
ps here you go:


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## zakruvalcaba (Jun 20, 2018)

markba633csi said:


> Someone had a procedure on rebuilding the head- if I can find the link I'll post it here
> Mark
> ps here you go:



Thanks Mark. I'm not interested in rebuilding the head at this point but it gives me a good idea of how the pulley assembly is removed. In this PDF he had to remove the pulley with a puller. Clearly mine is moveable up and down by hand....so somethings a miss and so I'll start there and assume, for now, that that is the source of the noise....


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## markba633csi (Jun 20, 2018)

OK understood, good little mill even if it needs a little fixing, I don't own one but I like to stockpile information just in case
Hello my name is MARK and I'm an information hoarder


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## wlburton (Jun 20, 2018)

markba633csi said:


> OK understood, good little mill even if it needs a little fixing, I don't own one but I like to stockpile information just in case
> Hello my name is MARK and I'm an information hoarder


I'm with you, Mark, about "hoarding" information, at least about machines that I own or expect to own one day (and I do own an 8520).  Not being one to want to reinvent the wheel when I can help it, I have created 3-ring binders for most of my machines where I put whatever manuals, brochures, parts lists, write-ups of procedures, etc. I come across in the cornucopia of information available to us on the internet (most of which couldn't have been found anywhere pre-internet).  I can sleep a little better knowing that if and when I need to rebuild the head of my 8520 I will have an excellent step-by-step guide to doing it.  Also, the next owners of these machines will probably be ecstatic to have access to these "books" after the big estate sale!

I'm reading this thread almost like a mystery serial and I can't wait to find out what the issue turns out to be.  The answer may well end up immortalized (printed out and lodged in a page protector) in my 8520 book!

Bill


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## zakruvalcaba (Jun 20, 2018)

wlburton said:


> I'm with you, Mark, about "hoarding" information, at least about machines that I own or expect to own one day (and I do own an 8520).  Not being one to want to reinvent the wheel when I can help it, I have created 3-ring binders for most of my machines where I put whatever manuals, brochures, parts lists, write-ups of procedures, etc. I come across in the cornucopia of information available to us on the internet (most of which couldn't have been found anywhere pre-internet).  I can sleep a little better knowing that if and when I need to rebuild the head of my 8520 I will have an excellent step-by-step guide to doing it.  Also, the next owners of these machines will probably be ecstatic to have access to these "books" after the big estate sale!
> 
> I'm reading this thread almost like a mystery serial and I can't wait to find out what the issue turns out to be.  The answer may well end up immortalized (printed out and lodged in a page protector) in my 8520 book!
> 
> Bill



I'm hoping it's simply a broken retainer clip that's causing the pulley to vibrate up and down and slap against the head. Like I mentioned in an earlier post, I reduced the speed to 600 RPM from the 1900 RPM that I had before and the machine sounds way better. Of course I'd like it to sounds exactly the same regardless of the speed I have it at. Perhaps I'll have some down time to work on it tonight.


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## markba633csi (Jun 20, 2018)

Isn't the internet great!?


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## zakruvalcaba (Jun 23, 2018)

So I'm 90% sure my noise is coming from my pulley being loose. I can't seem to pinpoint any other problem. I completely removed the cover and the noise is still there. So it's not the brake handle. I then attempted to remove the pulley. I started by attempting to remove the drive plate. I removed the two hex screws and the side spring loaded set screws but the drive plate seems to be fused to the pulley pretty good. The document for rebuilding the 8520 head makes it seem like this drive plate should just come right off....it doesn't. I also found the two set screws to be excessively loose. More on this in a bit. The video below shows me trying to slide the pulley up and off of the shaft but' it's binding on something. Again, I don't know WTF. So I gave up, slid the pulley back down and tightened the set screws. The pulley tightened up ok until I went to cut something. The pulley slid back up a tiny bit and the noise continued. Took the thing apart again and the pulley moves up and down. Granted it  requires some effort to move up and down but it's moving nonetheless. I'm not sure what's going on with this thing and I just want it to work. I sold my Rong-Fu to buy this mill in part because of it's cult following and right now I just feel pretty annoyed...


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## Briney Eye (Jun 23, 2018)

zakruvalcaba said:


> So I'm 90% sure my noise is coming from my pulley being loose. I can't seem to pinpoint any other problem. I completely removed the cover and the noise is still there. So it's not the brake handle. I then attempted to remove the pulley. I started by attempting to remove the drive plate. I removed the two hex screws and the side spring loaded set screws but the drive plate seems to be fused to the pulley pretty good. The document for rebuilding the 8520 head makes it seem like this drive plate should just come right off....it doesn't. I also found the two set screws to be excessively loose. More on this in a bit. The video below shows me trying to slide the pulley up and off of the shaft but' it's binding on something. Again, I don't know WTF. So I gave up, slid the pulley back down and tightened the set screws. The pulley tightened up ok until I went to cut something. The pulley slid back up a tiny bit and the noise continued. Took the thing apart again and the pulley moves up and down. Granted it  requires some effort to move up and down but it's moving nonetheless. I'm not sure what's going on with this thing and I just want it to work. I sold my Rong-Fu to buy this mill in part because of it's cult following and right now I just feel pretty annoyed...



You'll get it figured out.  Two socket head screws and two ground dowel pins hold and locate the plate on the top of the pulley.  It's probably just old hardened oil glueing it together.  Sharpen up a cold chisel and tap it into the seam between the plate and pulley, working all the way around the circumference.  It should separate.

That's an interesting draw bar and threaded spindle you have there.  I assume that you have the cap nut that screws onto the top of the spindle.  I've heard of the mod, but not seen it.  The flange on the draw bar is bigger than the depth of the splines, so the draw bar has to come all the way out.  Your pulley sleeve has a much thicker flange than mine, and I hate to say it, but is that a break around the inside edge that I see?  I'm afraid that the "sleeve" part has broken off from the flange, which would explain your whole issue.  You will need to braze it back together or make a new one.  Someone here can help you with that (maybe even me).

Don't give up.  I had to deal with several issues on mine, including silver brazing the broken brake plate, but I've made it into a really nice machine.

-Jon


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## zakruvalcaba (Jun 25, 2018)

Thanks for the guidance Jon, I got it apart (mostly). Not sure why I didn't think to remove the draw bar first. I can see that the pulley sleeve assembly is broken. Looking at the pictures up close, it looks pretty clear that someone had it break on them before and they attempted a fix that didn't hold. If that's the case, I may just make a new one. So with that said, two questions.

1) What's the best way to remove the broken portion of the pulley sleeve from the pulley without damaging the pulley? Press it out? Will the bearings just slide off or will they have to be pressed out as well? In the diagram, I see that there are 2 retainer clips in between the bearings so I'm not sure what the best way to get these off would be.

2) Is the pulley sleeve pressed into the flange or is it all one piece? If it's pressed in, what's the best way to remove the broken off piece that remains in the flange? 

Thanks in advance for any help!


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## Briney Eye (Jun 25, 2018)

Now that you have the top clip off, press the sleeve out through the pulley from the top.  It should push the bottom bearing out with it.  Impossible to say how much trouble the bearings will give you.  Sometimes the bearings just fall out/off (a good or bad thing depending on your point of view).  The top bearing in the rear cone pulley on mine was wallowed out several thousandths, and had to be sleeved and re-bored.  I also sleeved and re-bored the brake ring contact surface in the front cone pulley.  The end result was a very quiet machine and a brake that locks things up with just a little pressure on the lever.

I recommend replacing all of the bearings while you have it apart.  They're standard sizes, and inexpensive.  The only ones that I re-used were the thrust bearing on the knee screw and the quill bearings (but I have spares anyway).

-Jon


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## zakruvalcaba (Jun 25, 2018)

Briney Eye said:


> Now that you have the top clip off, press the sleeve out through the pulley from the top.  It should push the bottom bearing out with it.  Impossible to say how much trouble the bearings will give you.  Sometimes the bearings just fall out/off (a good or bad thing depending on your point of view).  The top bearing in the rear cone pulley on mine was wallowed out several thousandths, and had to be sleeved and re-bored.  I also sleeved and re-bored the brake ring contact surface in the front cone pulley.  The end result was a very quiet machine and a brake that locks things up with just a little pressure on the lever.
> 
> I recommend replacing all of the bearings while you have it apart.  They're standard sizes, and inexpensive.  The only ones that I re-used were the thrust bearing on the knee screw and the quill bearings (but I have spares anyway).
> 
> -Jon



Thanks Jon. Any idea on the broken piece of the sleeve still stuck in the plate? Is that part of the plate or can the remaining broken piece be pressed out? Also, why does the piece have to be brazed on? Seems like it can be welded back together just as easily with more strength. Is it a balance issue?


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## Briney Eye (Jun 25, 2018)

zakruvalcaba said:


> Thanks Jon. Any idea on the broken piece of the sleeve still stuck in the plate? Is that part of the plate or can the remaining broken piece be pressed out? Also, why does the piece have to be brazed on? Seems like it can be welded back together just as easily with more strength. Is it a balance issue?



Sorry to confuse you.  I see now that your sleeve appears to be tubing pressed into the flange.  Mine is turned from one piece.  Not knowing how it's retained (that looks suspiciously like JB-Weld around the edge), you will probably have to bore it out.  Making the replacement will be good practice fitting bearings to a shaft and cutting snap ring grooves.  Press it back in with LocTite 480 (or pretty much any LocTite, for that matter) and it ain't ever coming back out.  Ideally, you should do the final turning on the entire assembly.  If I were you I would decrease the ID as much as the quill will allow to make it less likely to break again.

-Jon


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## zakruvalcaba (Jun 25, 2018)

Briney Eye said:


> Sorry to confuse you.  I see now that your sleeve appears to be tubing pressed into the flange.  Mine is turned from one piece.  Not knowing how it's retained (that looks suspiciously like JB-Weld around the edge), you will probably have to bore it out.  Making the replacement will be good practice fitting bearings to a shaft and cutting snap ring grooves.  Press it back in with LocTite 480 (or pretty much any LocTite, for that matter) and it ain't ever coming back out.  Ideally, you should do the final turning on the entire assembly.  If I were you I would decrease the ID as much as the quill will allow to make it less likely to break again.
> 
> -Jon



Thanks again Jon. Sadly, I won't be boring anything out with my mill out of commission. I have a buddy that owns a machine / welding shop and so I'll just pass this project on to him. I'm out all next week on vacation so I'll update my progress when I return...thanks again!


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## zakruvalcaba (Jun 25, 2018)

Got the sleeve off. I've attached a couple of pictures. It obviously looks to have been replaced at some point. Whoever replaced it used thicker rod as the inside diameter is just about as wide as the spindle shaft. *I still don't understand why I can't just weld this back onto the plate? That should hold pretty well. Is it a balance issue?*

Also, take a look at the bottom of my pulley. It appears as though the brake plate was replaced by a custom-made aluminum piece that was then pinned to the pulley and screwed in. Can someone confirm? Seems weird that they would do that...

Also, the top bearing on my pulley needs to be replaced. I'll end up replacing both. Is there some kind of part number / link online for these?


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## Briney Eye (Jun 26, 2018)

What, you


zakruvalcaba said:


> Got the sleeve off. I've attached a couple of pictures. It obviously looks to have been replaced at some point. Whoever replaced it used thicker rod as the inside diameter is just about as wide as the spindle shaft. *I still don't understand why I can't just weld this back onto the plate? That should hold pretty well. Is it a balance issue?*
> 
> Also, take a look at the bottom of my pulley. It appears as though the brake plate was replaced by a custom-made aluminum piece that was then pinned to the pulley and screwed in. Can someone confirm? Seems weird that they would do that...
> 
> Also, the top bearing on my pulley needs to be replaced. I'll end up replacing both. Is there some kind of part number / link online for these?



You have an interesting challenge here.  I meant to mention the screws and pins and obvious wear, but I didn't realize that it was a separate assembly entirely.  Once the sleeve broke it ran a long time with that inside surface rubbing.

It's looking to me like the previous owner removed the brake plate/ring (8520-10 in the exploded diagram) and set it up so that the tab on the brake lever would wedge against the outer surface of the new piece added to the pulley, which is why it was pinned to resist the torque.  The brake lever normally sticks straight out from the side of the pulley guard, and I remember thinking it was at a weird angle in your earlier video.  Could you take a picture of the whole collection of parts?

In your earlier video it looked like the pulley sleeve flange was much thicker.  Was there a spacer under the pulley sleeve that we're not seeing here?

I think that I would turn a new sleeve from 4130 tubing, make it a light press fit, and "glue" it in with LocTite.  I would still try to beef up the wall thickness if there's any clearance.

-Jon


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## zakruvalcaba (Jun 26, 2018)

Briney Eye said:


> What, you
> 
> 
> You have an interesting challenge here.  I meant to mention the screws and pins and obvious wear, but I didn't realize that it was a separate assembly entirely.  Once the sleeve broke it ran a long time with that inside surface rubbing.
> ...



Yeah that's exactly what it looks like Jon. Seems odd to me that the brake lever was so critical to the owner of this machine that they decided to trash the original brake plate and completely fabricate a new piece that would mount onto the pulley. The original brake plate is now gone and the original pulley was permanently modified to accommodate this new piece. What a waste. I would have just remove the brake handle...I don't feel like it's that important....you can't wait an additional 3-4 seconds for the motor to stop?

The brake handle was modified too. They riveted a small piece of leather that then makes contact with the outer surface of this plate to bring the machine to a stop. I have to admit...it works...but I would never permanently alter this machine this way just for a brake.

There is no spacer in between the pulley sleeve flange and the head. Just the pulley sleeve flange.

I'll take your advice on the new sleeve. The ID of the sleeve is just about as thick as the spindle shaft so there's no making it any thicker. Personally, it seems thick enough to me already. You can see there's a lip on the sleeve tubing. That lip rests against the shoulder of the inner ring of the flange. I'm thinking perhaps it would be best to bore out the flange a little wider and just make the tubing thicker?

Zak


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## Briney Eye (Jun 26, 2018)

zakruvalcaba said:


> Yeah that's exactly what it looks like Jon. Seems odd to me that the brake lever was so critical to the owner of this machine that they decided to trash the original brake plate and completely fabricate a new piece that would mount onto the pulley. The original brake plate is now gone and the original pulley was permanently modified to accommodate this new piece. What a waste. I would have just remove the brake handle...I don't feel like it's that important....you can't wait an additional 3-4 seconds for the motor to stop?
> 
> The brake handle was modified too. They riveted a small piece of leather that then makes contact with the outer surface of this plate to bring the machine to a stop. I have to admit...it works...but I would never permanently alter this machine this way just for a brake.
> 
> ...



Aha!  It's all starting to make sense now.  That's actually kind of clever.

You need some kind of brake in order to tighten the draw bar.  I suppose you could use a pin spanner that fit into the sockets of the cap screws in the top plate, or the dowel pin holes if they're below the surface.  Or drill two more holes.  But then you need two tools to tighten it up.

Whatever material you start with, when you turn it down to fit the bearings leave as much radius at the transition as you can to minimize the stress riser.  The sharp inside corner is why it broke.

So you need to decide whether to keep the existing setup or fabricate a new brake ring, which is ductile iron.  Like I mentioned, I had to silver braze the two pieces of mine back together.  I'm sure it broke on yours too, but the previous owner came up with a different scheme.  I think they all break eventually because Clausing made a flexure opposite the brake handle by drilling a small hole and opening a slot on the inside edge.  Another stress riser caused by too small a radius.  It would have been much better to mill a 1/4" (or larger) radius bite out of the ring.  Or two.  Or three or four.  If you decide to go that route and do away with your extra pulley piece, I might be persuaded to do a drawing.

-Jon


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## zakruvalcaba (Jun 26, 2018)

Briney Eye said:


> Aha!  It's all starting to make sense now.  That's actually kind of clever.
> 
> You need some kind of brake in order to tighten the draw bar.  I suppose you could use a pin spanner that fit into the sockets of the cap screws in the top plate, or the dowel pin holes if they're below the surface.  Or drill two more holes.  But then you need two tools to tighten it up.
> 
> ...



I didn't think about needing the brake to hold and tighten the draw bar. I guess I didn't think about it because I'm using a collet holder that has two straight edges on both sides. I use a small adjustable wrench on the top of the draw bar and a crescent wrench on the collet holder to tighten. I guess I would have figured it out really quick if I ever put in standard collets or a chuck.

So I took the collar and plate over to my buddies shop and he recommended a different solution on the plate. He's going to reduce the diameter of the bottom of the collar where it meets the bottom of the plate and do a filler weld around the bottom of the plate...fusing it to the inside ring of the plate. He's then going to face both sides of the plate on his lathe to knock off those sharp corners on the inside hole of the top of the plate and any extra slag on the bottom of the plate. He's confident it will hold for many years. I drew up a quick and crude picture of the plan. Red representing weld around the circumference of the color/inner ring.


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## zakruvalcaba (Jun 28, 2018)

I have the plate done. I've attached some before and after images. I just need to file down some of the welding slag but other than that, happy with the way it turned out. Not original looking by any means but at least it's completely hidden from view and I don't think the collar will be breaking off any time soon. Ordered some new bearings for the pulley and then will reassemble.


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## markba633csi (Jun 28, 2018)

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


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## zakruvalcaba (Jun 28, 2018)

markba633csi said:


> 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....


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## markba633csi (Jun 28, 2018)

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


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## wa5cab (Jun 29, 2018)

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).


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## zakruvalcaba (Jul 13, 2018)

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.


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## Briney Eye (Jul 13, 2018)

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


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## zakruvalcaba (Jul 14, 2018)

Briney Eye said:


> 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...


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## Meta Key (Jul 14, 2018)

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


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## zakruvalcaba (Jul 14, 2018)

Meta Key said:


> 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
> 
> 
> ...



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.


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## Meta Key (Jul 15, 2018)

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


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## Meta Key (Jul 15, 2018)

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


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## zakruvalcaba (Jul 15, 2018)

Thanks for the detailed response. I agree I'm fairly novice here but the one thing I know how to do is remove and seat collets. I've done it hundreds of times with my round column RF31. In that mill, the spindle shaft is made to use a 22mm wrench to hold the spindle while you loosen the drawbar about 1/2 a turn. I then give the drawbar a whack with a hammer to drop the collet slightly then continue to unscrew the drawbar until the collet comes free and drops into my hand. I fully understand this process and I imagined the process would be the same with this mill. Again, something isn't right.

What I'm telling you and perhaps you can see this clearer by looking at some of my earlier posts, is that my collet was entirely seized in the spindle. I don't have a brake on mine, the previous owner jerry-rigged some custom setup but that's neither here nor there. My collet holder has flat edges so I can hold the collet holder while I tighten the drawbar. The main point of my argument is that it appears as though the collet holder is not seating correctly in the spindle....so when I tighten the drawbar it's bringing the collet holder too far into the taper (for lack of a better description) and causing it to seize. I don't how else to describe it. Like I said, I finally got it out but I'm hesitant to put it back in because of how hard it was to remove. I literally had to beat the living #@$% out of the drawbar to @#%^#% get the collet out. It's not right. Simple taps should work and I'm concerned that perhaps I'm doing something wrong. If you look at the video I posted above you can see that the collet holder appears to not fully seat....it gets caught on the taper....


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## Meta Key (Jul 15, 2018)

Good -- your procedure sounds correct.

In your video your toolholder seems to go way into the spindle before it encounters the drawbar.  How many threads are engaging when you tighten the drawbar?  I get 5 or 6 full turns of the wrench.  

Here is a toolholder (not a collet, more like what you're using in terms of the shank) being inserted.  First pic it has just contacted the drawbar, no threads engaged.



Second pic, drawbar fully engaged, about 5.5 full turns of the wrench.



Not sure what to make of your situation.  
Please do confirm that the toolholder *and* the spindle are both MT #2 and not the optional BS #7. 
You could also try some chalk or dykem blue on the toolholder to see if you're getting proper engagement of the toolholder in the spindle.

Meta Key


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## wlburton (Jul 15, 2018)

Does the collet holder get jammed the same with both spindles?  From your description it sounds like the MT2 might be galled, making the collet holder not slide in smoothly and then to become jammed.  On my 8520 I've never even had to tap with a hammer--turning the little wrench (which I made out of an upside down 1/4" socket plus a handle) against the cap loosens the collet enough to remove it.  Meta Key's point about checking to make sure it's not the BS #7 taper makes sense, too.  I've never seen a BS #7 taper so I don't know if they look similar enough for one to be confused for the other, though.

Bill


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## zakruvalcaba (Jul 15, 2018)

Collet holder shank is indeed MT2. I don't know anything about BS to be able to distinguish between BS and MT2 but the mill does say 8520 on it so I assume it's MT2. So I've attached 2 pictures. The first is the collet holder when it touches the drawbar in the spindle. I can then hand tighten the drawbar into the threads of the collet holder about 5 turns before I can't hand tighten any more. Then I use a small adjustable wrench, hold the collet holder in my hand and proceed to tighten the drawbar another half turn. Sounds identical to your procedure. The second image is the result of collet holder in the spindle after final tightening. I'm hesitant to tighten any further than that and end up in the same situation I was in before. Before, I used a large adjustable wrench, held the collet holder with the wrench in place by the visible flat areas and then tightened the drawbar tight. I'm wondering if too much force was placed on the drawbar when tightening, bringing the shank's taper of the collet holder too far into the spindle shaft causing it to seize once the force of the cutting motion was exerted onto the spindle / collet holder shank?


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## zakruvalcaba (Jul 15, 2018)

wlburton said:


> Does the collet holder get jammed the same with both spindles?  From your description it sounds like the MT2 might be galled, making the collet holder not slide in smoothly and then to become jammed.  On my 8520 I've never even had to tap with a hammer--turning the little wrench (which I made out of an upside down 1/4" socket plus a handle) against the cap loosens the collet enough to remove it.  Meta Key's point about checking to make sure it's not the BS #7 taper makes sense, too.  I've never seen a BS #7 taper so I don't know if they look similar enough for one to be confused for the other, though.
> 
> Bill



Bill, here's the collet holder in my spare spindle. It seats about the same distance into the taper as the spindle on the mill currently. The drawbar is a little wonky but it tightens down fine. The chance of both of these spindles being BS I would say are darn near impossible....


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## Meta Key (Jul 15, 2018)

OK, it looks like the toolholder is going in nicely and about the same as mine so I agree with you that the spindle is likely an MT2 taper.  I brought up the possibility because the B&S taper was an option and who knows what has happened with your mill over the years.  Sometimes guys will replace parts and not make a note of it -- kinda like the brake system on your machine.  Who knows what else has gone on there?  

Anyway, I'm with you Zak, I think the toolholder was just "in too tight" the first time.  Tightening it up with a short wrench and while holding the toolholder by hand (or another short grip on the other wrench) should be plenty tight.  I'd give it a try and see what happens.  Ya do not want the toolholder to spin independent of the spindle but start with light cuts and see what happens.  The Morse Taper is pretty dang grippy..

The other alternative is Bill's suggestion that the spindle might be galled in some way.  If a lighter touch doesn't solve the problem then a bit of dykem on the toolholder should show you if there is a problem with the spindle socket.

Meta Key


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## wa5cab (Jul 15, 2018)

And another possibility, if you find nothing wrong with the bore of the taper, is that the collet chuck had been in the spindle for a long time.


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## zakruvalcaba (Jul 16, 2018)

wa5cab said:


> And another possibility, if you find nothing wrong with the bore of the taper, is that the collet chuck had been in the spindle for a long time.



Good point but that wasn't the case. I just bought the set and it was in there for 1 project.


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## wa5cab (Jul 16, 2018)

OK.  I assumed that, like most stuck chucks on lathes, it was in the spindle when you bought the mill.  You probably over-torqued the draw bar, then.


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## zakruvalcaba (Jul 23, 2018)

Everything is back together and I made a few first passes on the mill using some 3/4" aluminum stock. At 600 RPM the noise is completely gone. The repair and new pulley bearings seemed to fix the noise problem. In terms of my stuck collet, I was very careful locking it down this time...so much so that I got some wobble on one of my passes....rocked the collet holder with my hands and it just popped loose. I need to find a happy medium between too damn tight and not tight enough. Anyway, tightened it down better and I made a second pass. Quality of the cut is just still not there.  Destroyed a 1/4" Hertel 4 flute and I suspect my speed may be the culprit. I'll make some more passes at the 1900 RPM setting with a 3/8" 3 flute cutter and see if my quality improves. Thanks again for everyone's help. Progress here to be sure...this noob just needs more time on the machine....


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## wa5cab (Jul 26, 2018)

According to the Atlas MOLO, the optimum surface speed for milling is about 2/3 that of the optimum speed for turning..  This is probably for HSS cutters.  Once the recommended SFM is known, the MOLO has a table that gives the RPM required with various size and type milling cutters to get a given surface speed.  There are copies of a couple MOLO's in Downloads.  The speed tables themselves are also there by themselves.


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## zakruvalcaba (Aug 9, 2018)

Something is still not right with this thing. I suspect the spindle bearings might need to be replaced. 1900 RPM...cuts are ok but it's making the loud noise again. Not as bad as before but significant. It also vibrates more than I think it should. Enough to loosen the knurled nut off of the top to the point where it almost flies off the drawbar.


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## GrayTech (Aug 9, 2018)

Do the sharpie test. Colour in the whole taper and insert it til it will l just rotate in the spindle. Take it out and see what the contact pattern looks like. 

Sent from my H3123 using Tapatalk


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