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Bad bearings? Dah Lih circa 1976 Taiwanese

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Ropata

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#31
That hex head on the taper index? Pretty sure no other fixings holding it. Tried a bit of heat. Might have to take it to an old Swiss machinist locally and see if he has any tricks.

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mikey

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#32
Do you have any large hex material laying around? You could bore to fit the cap and run a bolt through the side and into that screw hole on the side, then use a big wrench to apply more force. OR ... you can go see your friend. :)
 

Ropata

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#33
Do you have any large hex material laying around? You could bore to fit the cap and run a bolt through the side and into that screw hole on the side, then use a big wrench to apply more force. OR ... you can go see your friend. :)
Mate, that is a good idea but I think I might struggle to find 120mm hex around here. I do have the big wrench though.

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Ropata

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#34
Those are not screw holes on the side, they are just holes for a pin wrench.

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4gsr

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#36
Inspect that cap nut closely for the letters "LH". Gorton was real nice to do this. Of course after putting all effort into trying to break it loose, you happen to notice the letters LH. :confusion:

Another thing you could do, if you have another mill available to you, is to either cut a set of flats or a slot for a big spanner wrench. That way you have better bearing and less likely to shear off a "claw" as you do with a pin. Still think it's left handed....:boxed in:
 

Downwindtracker2

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#37
A rather common problem with 6200 series bearings is having them get axial preload . It's usually having either the wrong length spacer, spacer being too short, or no spacer at all. They get a notchy feeling ! If there has to be a preload, it has to be radial. I would guess that the clown before you jammed the nut into the thread end. A new pin wrench and some heat would be how I would attack it. The over tightening is a killer on 6200s. While 6200 series bearing do take some thrust loading, they have a deep race, but they are a basically a radial bearing . On one machine, I solved that by giving the operator a much shorter wrench. On your application the top bearing should be floating, whether on the shaft or housing. Thermal expansion has to have some place to go. When guys say don't mill on a drill press, I laugh. On my drill press the bearings are 6200s. You should only mill, not drill ! My guess your mill/drill is just a beefed up drill press.
 

4gsr

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#38
....................My guess your mill/drill is just a beefed up drill press.
I don't think so. If it is, it's the first one I've seen with both a horizontal and vertical spindles on the mill.
I highly doubt it has 6200 series bearing for spindle bearings in the lower end. More than likely 7200 series bearings, hopefully set properly at the factory. Unless someone has had this apart in the past and put the wrong bearings in the spindle. The upper bearing is more than likely a single 6200 series bearing, not two.
 

4gsr

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#39
If all else fails, take measurements of the cap on the outside. Then set up in a lathe and machine the cap down enough that it does not contact the housing face and attempt to remove. Just have to make a new cap afterwards. Applying heat to the housing to get it to let go could distort things as well as set fire to the oil or grease inside the housing. 400-500 degree F should be okay and no higher!
 

Ropata

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#40
I have turned up a sleeve and bored to just fit over the problem cap. I will drill and put pins in then weld on a long breaker bar. Hope this works.

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Ropata

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#42
Anyone have any idea what sort of maximum temperature I could get the quill up to before causing any damage?

Sorry 4gsr, just seen you posted earlier about max temp.
 

Bob Korves

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#43
There are probably precision bearings in there, quite expen$ive. Do not overheat them. I would not heat them over 150 F.
 

Ropata

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#44
There are probably precision bearings in there, quite expen$ive. Do not overheat them. I would not heat them over 150 F.
I'm trying to open it to get the bearings out for replacement but warping the quill I am worried about.
 

Bob Korves

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#45
I'm trying to open it to get the bearings out for replacement but warping the quill I am worried about.
300F (?) Don't want to temper the spindle hardness, much less warp it.
 

mikey

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#46
Wow, that is on there!

Before hitting it with a torch, I would consider welding a piece of hex stock in the middle of the yellow bar and trying an impact gun on that. If that failed then I would try a heat gun, and if that failed I would wrap the quill with a wet rag and try the torch.
 

RandyM

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#47
Are you sure they are not left hand threads?
 

Ropata

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#48
well l can't be 100% sure until It's off but I can't think of any reason why. I know a BP is right hand and someone mentioned one brand so far that is left. Can you think of any others that are left? Also I have wrenched pretty hard the other way too.
 

Bob Korves

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#49
My Burke Millrite has a left hand quill bottom thread.
 

Ropata

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#51
Ha ha, turns out it was left handed but it took a decent wallop and from the pictures you can see why. Must have got plenty of water in there at some stage. So now I'm after some advice on bearings. It has 2 x 7207 with spacer on the bottom and a single 6006 on the top. I don't want to scrimp on quality so if anyone has a good lead on quality bearings, I'm all ears.
20170819_152614.jpg 20170819_153804.jpg 20170819_160045.jpg
 

mikey

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#52
I chose FAG bearings when I rebuilt my spindle and went with sealed angular contact bearings with a P5 (equivalent to ABEC 5 class). These are high quality bearings that require no break in and no ongoing maintenance for the life of the bearings. Since they're sealed, no issues with water getting in, rust or debris/dirt will affect them. It has been less than a year since these went in but I'm still holding under 0.0001" TIR (just checked run out this week). What's more, they are still running fairly cool at high speeds so I'm happy with these bearings.

This is the equivalent bearing that I used but in the 7207 size: http://medias.schaeffler.com/medias/en!hp.ec.br.pr/72..-B-2RS*7207-B-XL-2RS-TVP

For the upper bearing, that simply needs to be a good radial bearing but I again suggest a 2RS (rubber sealed for life on both sides). I like Nachi deep groove bearings for this kind of application and this would be the equivalent of what I used: http://mortonmemorial.org/7260/NACHI-6006-2RS-Bearings-%7C-NACHI-6006-2RS-buy/.

While deep groove bearings are radial bearings, they also handle high axial loads and are a good choice when used as a guide bearing like it would be in your case.

The FAG and Nachi bearings I linked to can be found for good prices on the net.
 

whitmore

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#53
Ha ha, turns out it was left handed
Before putting good bearings in, I'd stamp LH in a few places....
Looks like the load wasn't what killed the spindle bearings, but a lube failure.

If you can find a local merchant for bearings, ask him; lubrication, cages, precision,
load ratings... preload... I'm sure it's all important, but it's beyond me.

There's a spate of counterfeits available 'on the internet'... and even a few stores.
<http://www.bearing-news.com/skf-destroys-15-tons-fake-bearings/>
 

Ropata

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#55
Before putting good bearings in, I'd stamp LH in a few places....
Looks like the load wasn't what killed the spindle bearings, but a lube failure.

If you can find a local merchant for bearings, ask him; lubrication, cages, precision,
load ratings... preload... I'm sure it's all important, but it's beyond me.

There's a spate of counterfeits available 'on the internet'... and even a few stores.
<http://www.bearing-news.com/skf-destroys-15-tons-fake-bearings/>
Yeah I'll certainly do something to remember but It's a bit hard for stamping.
 

brino

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#56
Ha ha, turns out it was left handed but it took a decent wallop and from the pictures you can see why.
Great! It is apart with no major damage. Congrats. Studied and slow is the way to go.

Yeah I'll certainly do something to remember but It's a bit hard for stamping.
How about a dremel type tool and a carbide engraving bit?

-brino
 

Ropata

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#58
Well they were so filthy and scored up
20170820_122602.jpg 20170820_122611.jpg 20170820_133309.jpg 20170820_133655.jpg
Has anyone ever seen this felt liner before? I'm guessing if I go for the sealed bearings I should just oil a new one up and insert it back in there?
20170820_132150.jpg
 

mikey

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#59
Has anyone ever seen this felt liner before? I'm guessing if I go for the sealed bearings I should just oil a new one up and insert it back in there?
If you go with sealed bearings, not sure what purpose a felt liner would serve. I would probably leave it out.
 

4gsr

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#60
I think I'd leave the felt shield in place. That would reduce the chance of contaminates getting to the bearing. Certain coolants including spray mist, can cause sealed bearing seals to become very spongy and eventually leak.
If it was me, I would try to machine a counter bore for a seal in the nut. That's what I did on my Index 645 mill. Of course, I got real smart and overfilled the bearings with grease and wound out blowing the seal out. Now, it oozes out yucky grease mixed with ISO46 oil.
I like the idea of sealed spindle bearings. Definitely something new. I assume, you can mount these in any configuration just like regular 7200 bearings.
 
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