Clausing 8520 Mill head noise diagnosis

Hi all, I hope I've chosen the right place to post this. I've recently acquired a Clausing 8520 vertical mill and it's got a pretty serious tapping noise in the mill head. It seems to be most pronounced under load and during interrupted cuts. From what I have been able to find from others it seems likely that I will need to rebuild the head but before I go and buy several hundred dollars worth of replacement parts I wanted to give you guys a chance to see/hear it and weigh in.

Clausing 852 mill - Noisy head - YouTube

So what do you guys think? Time for new bearings or do you think I have a different issue?

It sounds as if the brake is dragging, or someone replaces an all cap screw and it was to long and it's dragging on something each revolution. How does the belt look? If you remove the belt and spin it by hand can you feel a drag?
I found this manual for you to look at.
http://vintagemachinery.org/pubs/182/10558.pdf

Pretty simple design, so i bet the repair would be cheap enough.

Another trick is to go to an auto store and buy a stethoscope and listen on the head where the noise is the worse.
A long screw driver works too, but not as good. I see your fly cutting, that makes that noise too. What happens when you not milling?

Lets us know what you find. Rich

Thanks for the insights Rich, I'll take a close look when I get home and report back. The tapping is definitely separate from the fly cutter noise and coming from near the top of the head but you might be onto something with the brake. I received an extra one that was broken in half with the mill so it was apparently recently replaced. I should have suspected that earlier, maybe I was just assuming the worst. If I remember correctly the noise goes away when not milling, hence fly cutting during the video to put on some load and to interrupt the cut. I'll confirm that as well and pull off the belt to get a good hand feel of the rotation.

Thanks a lot,
Korey

Another trick is to go to an auto store and buy a stethoscope and listen on the head where the noise is the worse.
A long screw driver works too, but not as good.

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I'm confident that my 2-foot piece of radiator hose was a highly calibrated piece of equipment but since it didn't yield any results I guess there is probably room for improvement.

KVandy15 said:

Hi all, I hope I've chosen the right place to post this. I've recently acquired a Clausing 8520 vertical mill and it's got a pretty serious tapping noise in the mill head. It seems to be most pronounced under load and during interrupted cuts. From what I have been able to find from others it seems likely that I will need to rebuild the head but before I go and buy several hundred dollars worth of replacement parts I wanted to give you guys a chance to see/hear it and weigh in.

Clausing 852 mill - Noisy head - YouTube

So what do you guys think? Time for new bearings or do you think I have a different issue?

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A couple of things could be wrong there - impossible to say. It's a simple machine, just take the head apart and you will immediately see what's wrong. Otherwise, we could speculate here endlessly and it's really no helpful.

Richard King said:

Lets us know what you find.

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I took the top of the head apart tonight, hand feel of the spindle says one or more of the spindle bearings are in rough shape. The pulley bearings and brake seem fine but my drawbar is also in worse shape than I thought. I've got an email out to Clausing about the bearings, I'm going to try and keep the mill operable until I can line up the parts. I think I'll have a go at making a drawbar in the meantime.

I tried making a video of the bearing noise but you have to turn it up a lot to hear it. Clausing 852 mill head bearing - YouTube

I'll follow-up with what I hear back from Clausing, I'm expecting they are out by now but doesn't hurt to ask. I found a few posts of people who found suitable aftermarket replacements so solutions exist either way.

Thanks Rich, and guy who said to just take it apart, you were helpful too in a way.

I see your in MN, where? Buying the bearings from Minnesota Bearing, Tull Bearing or Gopher Bearing will probably be less 50% compared to Clausing. They will be numbered and those 3 places should have them in stock. They won't have a clue if you call and say it's for a Clausing, you will need to take it completely apart ad get the numbers off the bearings. The top bearing looks like it shielded or sealed. That would be good so you won't have to oil them.

If you were in the twin cities I would come and help you, but I'm going on a business trip Wednesday. If you decide to do it yourself Buy a snap ring pliers and if you not familiar with installing bearings, check out you tube. Don't use a punch to hammer on the new bearings. Or you can call me and I can help or I know most of the rebuilders in the area that could help, but they are pricey. send me a Private Message with your number and I can call. Rich

Richard King said:

I see your in MN, where? Buying the bearings from Minnesota Bearing, Tull Bearing or Gopher Bearing will probably be less 50% compared to Clausing. They will be numbered and those 3 places should have them in stock. They won't have a clue if you call and say it's for a Clausing, you will need to take it completely apart ad get the numbers off the bearings. The top bearing looks like it shielded or sealed. That would be good so you won't have to oil them.

If you were in the twin cities I would come and help you, but I'm going on a business trip Wednesday. If you decide to do it yourself Buy a snap ring pliers and if you not familiar with installing bearings, check out you tube. Don't use a punch to hammer on the new bearings. Or you can call me and I can help or I know most of the rebuilders in the area that could help, but they are pricey. send me a Private Message with your number and I can call. Rich

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What a legend, thanks for the tips on sourcing the bearings locally and the offer for help, you are too generous. I did get a response from Clausing and the prices are premium to say the least. I will get the numbers from the bearings and reach out to one of these companies. I found a really helpful video from another guy who has done this bearing replacement and a text guide to rebuilding the head that will both come in very useful so I should be well on my way. If I do need more help though I will certainly reach out, I'm in Apple Valley so only a short drive away from you in Cottage Grove.

Clausing 852 spindle bearing replacement and power feed demonstration - YouTube - Video that shows bearing details
http://wentztech.com/WebDisk/Metalworking/Clausing/Freds - Rebuilding the 8520 head.pdf - Head rebuild walkthrough


Prices I received from Clausing (I had them price out basically all the head components for me):

Part# - Description - Price(per) - #Req'd - Note
556-020 - Plate - $379.96 - This plate connects the Spindle shaft to the Pulley set, mine has some play here but not $380 worth, DIY replacement seems viable but I'll save that for later.
044-007 - Bearing (Head pulley) - $64.32- 2 - It's a few bucks extra for a second one as they only have 1 in stock at the moment.
044-016 - Bearing (Head, top) - $41.56 - 1
537-020 - Nut (Spindle) - $7.36 - 1
932-011 - Washer (Spindle) - $1.28 - 1
699-153 - Spacer (Spindle) - $69.08 - 1 - Anecdotal evidence says this is often MIA, I'll have to investigate mine
044-005 - Bearing (Spindle) - $131.03 - 2 - This is the angular contact bearing matched set
708-001 - Oil seal (Spindle) - $25.72 - 1
641-008 - Retainer (Spindle) - $65.88 - 1
8520-16 - Draw Bar Assembly - $117.04 - 1 - I'm going to just make one of these.
547-002 - Oiler - $5.64 - 1
DB4-35 - Oiler - $5.60 - 1
044-004 - Bearing(Overarm) - $29.84 - 1 - Overarm pulley set bearing (top)
044-003 - Bearing (Overarm) - $35.44 - 1 - Overarm Pulley set bearing (Bottom)

Thanks again, I'll update soon.

I wrote a bigger post but it's apparently awaiting approval? Hopefully this TLDR version works. I went to Tull today.

I don't want to wait for the approval of my other post to say thanks for the offer of help Rich. I am just a short drive away in Apple Valley but I don't think I need a house call yet, that is a very generous offer.

I might be interested in trying to setup some beginner level scraping instruction in the long term though, I've got a few friends I think would get on board and probably my dad too. After I get the mill tuned up I've also got a South Bend 10K that needs a complete overhaul, if I want to do it right I think I'm going to need some training and practice.

On the bearings you were so helpful, Tull Bearing had a pair in stock for 45 each, Clausing wanted 130 each. I did order a few of the more reasonable parts from Clausing as well, hoping that stuff will come before the weekend but I don't think it shipped today so not too confident.

Edit: My other post is up now, with all the Clausing pricing on it. See 2 above.

Doing the head rebuild tomorrow + Idler, I'll try to take some footage since I couldn't find any.

I'm down in GA now teaching a class and in 2 weeks I go to Germany and UK to teach scraping classes. I'll be home on Tuesday. If you don't have the bearing put back on I can lend you a bearing heater so no pressing on the bearing on the shaft would be needed. Or If you have heat in your shop I could drop by in January and say hi and bring a scraper and give you a demo. Would be fun to shoot the breeze too. Private Message me and I'll give you my phone number. I have a small company in Mound that wants to do a scraping class. We could do one in January. He is a former student who now rebuilds Studer Grinders. Rich

Thanks for the offer on the bearing heater, I didn't even think of that. All the guides I've read just say to press it. What kind of temperature would be necessary? I've got a shop toaster oven and an electric kiln, I can probably work something out.

Joining in a class or getting a demo sounds like it'd be a real privilege, I sent a PM with my contact info.

I'm hearing about 220F (105C) should do it. I'll shoot for that.

KVandy15 said:

I wrote a bigger post but it's apparently awaiting approval? Hopefully this TLDR version works. I went to Tull today.
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What are these NACHI bearings for ?

KVandy15 said:

View attachment 211941
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Doing the head rebuild tomorrow + Idler, I'll try to take some footage since I couldn't find any.

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What is the "Read "n" Tacky" thing ? Is it some sort of agricultural grease ?

That temp sounds to high. Check out SIG website and search bearing heaters. That's where I look when I do it. I would recommend Mobil Red Horse grease. # 28. It's what Heals Red Head spindle head used. It's an great grease and not to expensive. Rich

I have replaced those bearings when I had the same mill. I did not use a bearing heater, I just pressed them in with an arbor press. You really don't need a lot of force. One or 2 tons would be all you need for most bearings.

My lesson learned from the process was DO NOT FILL THE BEARINGS ALL THE WAY with grease. You just need 33%. The trick, which I learned to late ... is to fill the bearing 100% from the 12 O'Clock position to the 4 O'Clock position, and then rotate the bearing to spread the grease out.

When you over fill the bearings the grease "churns" and heats up. In the top 2 speeds the spindle/quill becomes to hot to hold (not good). And it's actually hard to remove the extra grease without removing the bearings.

Vince

Thanks for all the inquiries/feedback. I didn't end up getting to the mill head today after all, it sounds like I might want different grease from responses so I might hold off on doing it tomorrow unless I can find the grease locally.

AlexO said:

What are these NACHI bearings for ?

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Those are the main spindle bearings, set of 40 deg angular contact bearings.

AlexO said:

What is the "Read "n" Tacky" thing ? Is it some sort of agricultural grease ?

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Was what I planned to use on the spindle bearings, I had seen it recommended but can't seem to find where now. I'll probably take Rich's suggestion on the Mobil 28 I guess?

Richard King said:

That temp sounds to high. Check out SIG website and search bearing heaters. That's where I look when I do it. I would recommend Mobil Red Horse grease. # 28. It's what Heals Red Head spindle head used. It's an great grease and not to expensive. Rich

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I'll do some more research on the bearing heat and see if I can find that grease.

Vince said:

I have replaced those bearings when I had the same mill. I did not use a bearing heater, I just pressed them in with an arbor press. You really don't need a lot of force. One or 2 tons would be all you need for most bearings.

My lesson learned from the process was DO NOT FILL THE BEARINGS ALL THE WAY with grease. You just need 33%. The trick, which I learned to late ... is to fill the bearing 100% from the 12 O'Clock position to the 4 O'Clock position, and then rotate the bearing to spread the grease out.

When you over fill the bearings the grease "churns" and heats up. In the top 2 speeds the spindle/quill becomes to hot to hold (not good). And it's actually hard to remove the extra grease without removing the bearings.

Vince

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That's what I was planning to do, just press them on but, if heating the bearing makes it easy I'm well equipped for that. Especially if we are only talking a couple hundred degrees. I've got a little toaster oven with adjustable temp on it that I use for preheating casting stuff, it should do the trick just fine.

Thanks for the heads up on the grease ratio, I did find that in the guides I found as well. Seems more than a few heads have been rebuilt due to that error.

I was thinking 140 F and found this link.
http://www.lubsys.com/knowledge/knw_heatmnt.htm You could call Tull and ask them too. If it's a thrust bearing be sure to mount them the way it came part. I would think "back to back" or thick outer races facing each other. Those are some small bearing so I would go to the low end of the scale. I also have a hand held infared thermoemeter that measures temp. Its nice and cheap from Granger. There are several you tube shows on bearing heaters.

PS. Also the Mobil grease # 32 is an updated version of #28. I used to buy it in 1/2 pound tins. You could also call Craig Laurich of Shop Services in Buhl MN or Rick at A&D Machining Rebuilding of Roberts WI and ask them what they use. Tell them I said Hi. I agree with the 30% pack. Once you use a bearing heater method, you will never press one on again. For those other members reading this never hammer and punch one on.

Here you go. LOL: Get Smart Too with SKF Maintenance Products - YouTube

Richard King said:

I was thinking 140 F and found this link.
http://www.lubsys.com/knowledge/knw_heatmnt.htm You could call Tull and ask them too. If it's a thrust bearing be sure to mount them the way it came part. I would think "back to back" or thick outer races facing each other. Those are some small bearing so I would go to the low end of the scale. I also have a hand held infared thermoemeter that measures temp. Its nice and cheap from Granger. There are several you tube shows on bearing heaters.

PS. Also the Mobil grease # 32 is an updated version of #28. I used to buy it in 1/2 pound tins. You could also call Craig Laurich of Shop Services in Buhl MN or Rick at A&D Machining Rebuilding of Roberts WI and ask them what they use. Tell them I said Hi. I agree with the 30% pack. Once you use a bearing heater method, you will never press one on again. For those other members reading this never hammer and punch one on.

Here you go. LOL: Get Smart Too with SKF Maintenance Products - YouTube

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Back-to-back is right on bearing orientation, I'll start low with the temps, more like 140F and see how it goes. I've also got an infrared thermometer so I'll keep an eye on it with that.

I already put an order in for a tube of #28 so I think I'm committed there, I did get a chance to talk to Rick @ A&D about my lathe when I picked that up, I'm expecting to use his services for getting the ways re-ground when I get to that point.

Haha, That video is great, surprisingly informative.