Burr King Disassembly / Bearing Replacement -- how do you get it apart?

C

catalytic

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Jul 19, 2011
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I just picked up my first grinder -- a Burr King 760 -- last weekend. I have rebuilt a wide variety of machine tools, but this is my first grinder. From the sounds its making, it will need bearings throughout (which I was expecting). Also, the drive wheel has a nasty wobble, leading me to believe that the drive shaft may be bent (which I was not expecting).

Can anyone give me some help as to (1) how to remove the idler wheels and get to the bearings and (2) how to remove the drive wheel shaft? I would also appreciate any thoughts on the bent shaft -- I've seen a lot of damaged machine tools, but it's hard to imagine how you'd bend the short shaft without damaging the casting / aluminum wheel. The previous owner left a really tightly tensioned belt on it for a couple of months before selling it, if this is relevant (I would think this would make a flat spot, not a wobbly wheel/shaft though!)

Here's the machine. I know not many of you run this particular model, but I believe the idler wheel/shaft/bearings setups are very similar to the knifemaker model.






 
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Thank you for the reply. There are no external snap rings on the idler wheel shafts -- the dark rings in the picture where the parts schematic says that snap rings should be located are just the bearings (they read "KOYO JAPAN" -- a leading bearing manufacturer -- in tiny letters). Perhaps this model predates when they started using snap rings?

One more detail: the previous owner left a belt very tightly tensioned on the machine for a couple of months before selling it. I still don't believe this explains the severe wheel/shaft wobble, though.

Here are bigger pics of the drive wheel shaft (drive wheel removed) and the rear idler wheel that I'm not sure how to remove:


 
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I think this machine tracks off the rear wheel, not the drive wheel. I don't see any snap rings on the idler shafts, but that doesn't mean they aren't supose to be there. It's possible a previous owner attempted to replace the bearings and got as far as getting the snap rings off and then gave up when the wheels didn't just fall off in his hands. I will usually get a magnifing glass out and look at the area a little closer to see if there are any signs of a ring being there at some point. You could also call the factory and get their input.
 
there should be an allen head set screw in the tensioner assembly that holds the idler shaft in place. To remove the drive wheel first loosen the set screws and remove the wheel guard and then the tool rest arm. After that remove the belt guard and drive pulley behind the drive pulley there are three bolts holding the bearing cartridge in the frame. Burr king tells you that you have to buy the assembly but I was able to press mine apart and replace only the bearings in it but I guess it depends on the date of manufacture. the idler wheel and tensioner assemblys have the bearings pressed into the wheels and then the shaft pressed into them and held by snap rings.
 
Thanks guys -- following your advice I got the idler wheels/shafts off and also the drive wheel bearing assembly. I'm stuck on the next step, though. First, can I press the shafts out of the idler wheels on the shop press, pushing on side of the shaft on the front/face side of the wheel? Here are the idler wheels:






Second, I have not been able to get the drive wheel guard/tool rest arm off of the drive wheel shaft/bearing assembly. There is a cast retaining ring (#1 in the pic below) that is stuck (pressed on?), and also the wheel guard (#2 in the pic) will not move towards it. Can I put a bearing puller on these or is there a flange/something keeping them from coming off to the right?

 
catalytic said:
Thanks guys -- following your advice I got the idler wheels/shafts off and also the drive wheel bearing assembly. I'm stuck on the next step, though.

First, can I press the shafts out of the idler wheels on the shop press, pushing on side of the shaft on the front/face side of the wheel? Here are the idler wheels:



Second, I have not been able to get the drive wheel guard/tool rest arm off of the drive wheel shaft/bearing assembly. There is a cast retaining ring (#1 in the pic below) that is stuck (pressed on?), and also the wheel guard (#2 in the pic) will not move towards it. Can I put a bearing puller on these or is there a flange/something keeping them from coming off to the right?
Click to expand...

I'd use a puller, or press, not a hammer, that would upset the shaft and make the bearing press fit tighter

It's possible they used a loctite type glue on the bearings, try a bit of soft propane flame on the outside of the aluminum wheel boss




Have you removed screw beside arrow number two?
It looks like that split and screw clamps it
http://i935.photobucket.com/albums/ad200/Dartmouthmtb/IMG_0131_driveshaft_zps6d263053.gif
I suspect that is holding that bearing in, too narrow for other means ?
 
12345678910 said:
I'd use a puller, or press, not a hammer, that would upset the shaft and make the bearing press fit tighter

It's possible they used a loctite type glue on the bearings, try a bit of soft propane flame on the outside of the aluminum wheel boss




Have you removed screw beside arrow number two?
It looks like that split and screw clamps it
http://i935.photobucket.com/albums/ad200/Dartmouthmtb/IMG_0131_driveshaft_zps6d263053.gif
I suspect that is holding that bearing in, too narrow for other means ?
Click to expand...

Thanks for the reply. The screw is completely loose -- I removed it, then put it back after failing to remove the guard so I wouldn't misplace it. The arm slides about 3/32" left and right. When it goes left, it gets looser (but then bumps into the tool rest arm). When it goes right, it gets stuck. I could probably get a 2-arm puller on it and see if a very gentle pull will get it going to the right. Given that its just a little casting, I wanted to check with you guys first in case there's something stopping it before really giving it a pull.
 
to push the shafts out of the idler you need to put a support of some kind under the bottom bearings or take the chance of bending the idler wheels. remove the screws in the guard and tool rest and slightly wedge the pinch clamp apart. the guard etc on my burr king slides over the inner drive hub.
 
Bill Burke said:
to push the shafts out of the idler you need to put a support of some kind under the bottom bearings or take the chance of bending the idler wheels. remove the screws in the guard and tool rest and slightly wedge the pinch clamp apart. the guard etc on my burr king slides over the inner drive hub.
Click to expand...

Bill -- thanks very much for this. You were right, I got it all apart now. there was a tiny burr on the edge of the inner piece keeping it from moving -- a few minutes with jewelers' files and it came apart easily.

Two quick questions: if I understand correctly, when I go to remove the shafts/bearings from the idler wheels, you say I should press just the shafts out first (leaving the bearings in the wheels). Is this correct?

Second, how tight is the upper wheel tensioning hinged arm supposed to be? The hinge on mine is so tight I can lift the whole machine up by it without it budging (it does move, but it takes some force). I know this is too tight (unscrewing the tracking knob does nothing since the hinge stays put), but I'm not sure how freely they're supposed to move. Here's what I'm talking about:

 
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Thanks -- I really appreciate your help. Can you tell me why you recommend pressing the shafts out of the idler wheels first rather than pressing the shaft-and-bearings together out of the idler wheels? (I have no idea what the bearing arrangement is on the inside of these wheels -- according to what I can find online, the idler wheel design changed in 1995, and my machine is earlier than that.)

Thank you again,
Adam
 
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on mine there is a step inside the wheel that the bearing s rest against to keep them from only going in so far then a snap ring to keep them in place. So you press the shaft out then with the snap rings removed put a drift through the shaft hole in one bearing and tap the opposite side bearing out. flip the wheel over and tap the bearing on the opposing side out.
 
Bill Burke said:
on mine there is a step inside the wheel that the bearing s rest against to keep them from only going in so far then a snap ring to keep them in place. So you press the shaft out then with the snap rings removed put a drift through the shaft hole in one bearing and tap the opposite side bearing out. flip the wheel over and tap the bearing on the opposing side out.
Click to expand...

Great -- this is really helpful.
 
Did you get the shafts and bearings pressed out and did you go with burr-king bearing or aftermarket have a 960 250 with same deal no snap rings .
 
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