[LeeWay]

Especially true with electronics.

[_swede]

Well after reading through nearly 100 posts I was kind of disappointed that I didn't find a quantitative answer for the spindle nut pre-load torque.

I recently noticed a slight vibration in my spindle. It is audibly detectable as a 'knocking' especially at lower speeds. Of course as the spindle speeds increase, the frequency of the vibration follows suit but is almost entirely drown out by the normal operating noise of the motor.

I purchased my machine (SN: 1333) last November, right about the time this thread began. Somewhere in this thread it was said that (and I paraphrase) the problem with incorrectly installed spindle bearings may extend past a few machines. And I don't recall anyone disputing that...

I understand the process of removing the pulley, spindle nut and washer in order to check if the bearings are in fact installed correctly. However, I am firmly against the idea of removing the spindle nut without first having an appropriate torque value to reinstall it.

To whomever was in contact with Greg directly: Did you end up getting a definite spindle nut torque value?????

I use this machine very often for my business... I'm sure this is the case for many of you on here. I can tollerate the noise for the time being, but I can sense pending doom (e.g. bearing failure, spindle damage, scrapped work). I'd like to be proactive and figure out what the issue is BEFORE mine are squealing like the other two machines on here.

Things I've tried thus far: I removed the V-belt to determine if the motor was the source of vibration (it wasn't). I removed the drawbar/R8 collet for the same reason (they weren't). I have run the spindle with the safety door open by manually holding the door interlock switch (there is no visible evidence of the pulley or anything else being unbalanced). The vibration is not very intense but detectable by touch on the outside of the head casting.

Do my symptoms describe bearings on their way to failure??

Thanks, everyone.

-swede

[keen]

Hi swede -This may be a quick reply at this stage. I would order and have ready a replacement set of bearings ex tormach - they are not expensive and are good quality. I would buy a tube of the spindle grease also(above posted details) . If the bearings are making the noise I doubt changing the preload will help much.

The spindle design with bearings a long way apart is good for ridgidity - but thermal expansion due to spindle temp increase more than the cooler bearing housing means preload will drop off once the spindle heats up - this means any preload will be much less or gone altogether. So the setting is going to be a comprimise - thats why I installed a spring disc preload. (Works really well).