# Issues With Bf20vl (g0704's European Identical Cousin)



## kizzap (May 10, 2016)

Hey guys hope you don't mind me jumping in here to ask questions, but I figure I'D ask here, considering that the two mills are clones of each other. Please keep in mind I would class myself an extreme beginner, having only owned the mill 6 months or so, with the last I have used any form of machinery of the form was around 10 years ago in high school...

So basically what happened is while using a roughing end mill to bring a piece of stock down to size, I ended up crashing the head a bit, which has caused some issues in the mill, with the mill getting a good load of vibration occuring, and an intermittent kind of rattling noise, and a lot of noise.

I started pulling the mill apart and ended up pulling out the gear assembly which the spindle is mounted in out. The gear on the low speed side's (the smaller gear's) bearing had obviously bought the bullet, and was really rough. So I figured at this point I would be best to replace both bearings on that shaft. 

I then reassembled the mill, and found that while some of the noise was gone, there is still an intermittent rattle, and vibration, and some minor noise. I have tried greasing up some parts, which has aided in reducing some of the rattling noise, but there still is the issue.

However the interesting thing I have found, which I don't know if this will aid in the problem solving, is that all the major noises, etc, only happen while the mill is in the low gear range. If I run the mill in the high range, there still is some noise, however it is extremely minor. It is leading me to consider if maybe the lower bearing on the intermittent shaft is shot, or, would that be an unlikely scenario, and would it be the angular bearings in the spindle that need attention?

*TL;DR: Crashed mill. Mill now making an intermittent rattling noise while in low gear selection. Replaced bearings on spindle drive shaft, which helped some, but not 100%. Could a crash damage the bearings on the intermediate shaft in the gearbox?
*
kizzap


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## coffmajt (May 10, 2016)

kizzap said:


> Hey guys hope you don't mind me jumping in here to ask questions, but I figure I'D ask here, considering that the two mills are clones of each other. Please keep in mind I would class myself an extreme beginner, having only owned the mill 6 months or so, with the last I have used any form of machinery of the form was around 10 years ago in high school...
> 
> So basically what happened is while using a roughing end mill to bring a piece of stock down to size, I ended up crashing the head a bit, which has caused some issues in the mill, with the mill getting a good load of vibration occuring, and an intermittent kind of rattling noise, and a lot of noise.
> 
> ...


You may have caused the bearing preloads to have changed, which if too loose can cause vibration and noise even if the bearing are good. Jack


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## kd4gij (May 10, 2016)

Do you have some thing in the collet?


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## kizzap (May 11, 2016)

coffmajt said:


> You may have caused the bearing preloads to have changed, which if too loose can cause vibration and noise even if the bearing are good. Jack



Will have to pull the quill out and have a look at this. If the fix is this simple, I will rejoice. I guess at least I can try this prior to trying anything further. I might even just remove the quill and see if that solves the vibration issue, will help isolate the problem at least



kd4gij said:


> Do you have some thing in the collet?



Yeah, I have have a drill chuck in at the moment, but the noise level stays the same irregardless of if there is something there or not.


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## kizzap (May 12, 2016)

Ok, so I pulled the spindle today, and tried it out. Still getting a lot of noise. At the point of considering replacing all the bearings I can find...


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## kizzap (May 18, 2016)

Not sure if anyone is following this, I suspect not. 

Definitely bad bearings in the spindle, found if I put a little bit of load on the chuck while running, the noise vanishes. Trying to find replacement spindle bearings now, as the lower bearing had some obvious issues, with the bearing cage  is all sorts of deformed, and not running smooth at all. however I am now in the unfortunate stage where I need to source a replacement bearing, which my local shop is struggling to source. (if you are curious the bearing is a HR32906 30x47x12). My bearing guy tried all his suppliers in Australia, and there is NOTHING in the country. He is now having to stretch his feelers overseas.

I am currently investigating an alternate solution for if it comes to it. (Needle roller / angular contact ball bearings maybe) My concerns are that I dont have the same space for the lower bearing as you all have, meaning the bearing external dimension is limited to 47mm (MT3 spindle BTW)


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