High RPM noise

[RMAC]

We have a 1997 VF 6 that in the last year has developed an ear piercing scream, squeal but continuous. If you remember the old generation TVs and their high pitch noise, just amplify that 50 to 100x and you get the idea. Or if you can't picture that, just imagine an extreme case of tenitus.

In the lower RPM range of 3000 and below life is good. By 5000 RPM the noise is very loud and remains about the same as far as pitch and volume from that point all the way to 10,000. You have to wear ear plugs just to run operate the machine and it has become the most hated machine in the shop for this reason.

I am 90% convinced it is the transmission gear play making the noise. I have already tested the belts as a cause by tigheten and loosing them and nothing I did with the drive belts would change the noise.

Does anyone else there have experience with this problem or have suggestions?

[haastec]

Probably the bearings in either the transmission or the motor itself. To rule everything else out, completely disconnect the spindle belts and run the motor/transmission at the rpm's you were hearing the noise.

Good luck and let us know what you find.

[RMAC]

Originally Posted by haastec Probably the bearings in either the transmission or the motor itself. To rule everything else out, completely disconnect the spindle belts and run the motor/transmission at the rpm's you were hearing the noise. Good luck and let us know what you find.

After a chat on the phone with my friendly HAAS service dept. I was advised to eliminate the cause of the noise by disconnecting the drive belts that connect the spindle to the Motor/gear box assy and see if the noise occurs then. After disconnecting the belts I was surprised to find it was not the motor or gear box.

Next I was to reconnect the belts to the spindle and retension the belts with a much slacker tension than I had before. Upon doing so, I noticed a signicant reduction in the noise. Even at the slacker tension they still are noisy but not as bad as they were.

So I think it is now a belt issue and not worn out spindle bearings. I am ordering new belts to replace the old ones today.

[Haas__man]

Before fitting the new belts you should clean both pulleys (spindle and motor) I would suggest using a toothbrush and some degreaser. Give them a good clean - then re-fit the belts.
To get the correct belt tension, I usually find that if I increase belt tension until the belts can no longer slide up and down the pulley - then its perfect. After you have tightened transmission bolts - spin the spindle a couple of times and re-check tension to see if it has changed.

Hope this helps.

[RMAC]

Originally Posted by Haas__man Before fitting the new belts you should clean both pulleys (spindle and motor) I would suggest using a toothbrush and some degreaser. Give them a good clean - then re-fit the belts. To get the correct belt tension, I usually find that if I increase belt tension until the belts can no longer slide up and down the pulley - then its perfect. After you have tightened transmission bolts - spin the spindle a couple of times and re-check tension to see if it has changed. Hope this helps.

Thanks very much for the advice!