VF3SS spindle clunk

[sjr]

Hello!

I have a 2003 VF3ss - the spindle has just started making a "clunk" noise anytime you start the spindle. If you hold on to a toolholder while in the spindle and rotate it back and forth, you can feel the "clunk" each time you change direction. With the spindle running, if you manually increase or decrease the rpm, you can hear it as well. Upon a Haas service techs phone advice, we replaced the lovejoy like coupler at the top of the spindle - did nothing. Then service guy came to the shop and hooked up his special tool to the spindle - said spindle is bad. I am not buying into that just yet.

To complicate things further - at the same time, I am now having a more difficult time than usual when trying to machine any type of steel. Absolutely no rigidity whatsoever. Even trying to use a 3/8 4 flute carbide endmill as a counterbore tool - while pecking in the z, you can hear and basically feel the vibration! The bottom of the cbore is all chattery and unacceptable. Also much vibration when trying to take a finish pass with a 1.00 diameter x 3.00 LOC 3 flute endmill on a large aluminum block.....only in the x minus direction though???

While taking a conservative cut in a steel block, I put my hand on the spindle housing and could not feel any obvious vibration.

The spindle sounds the same as it always has - nothing unusual at any rpm - no whining at high rpm - don't usually run above 10K except for 1/16 em's - which isn't very often at all.

We have tried narrowing it down further with no luck. Any of you have thoughts on what might be happening?

Thanks!
sjr

[CEP Inc.]

How many hours are on the spindle? Did the tech say specifically what was wrong with the spindle other than its bad?

[Hdpg]

Have the drawbar tension checked. It sounds like you might have some broken Belleville washers inside the spindle.

[HuFlungDung]

Hdpg's suggestion is a good one. Even in the absence of a drawbar force gauge, you can pry down on the toolholder flange and get some quick idea if something is drastically amiss.

It would have to be really loose to actually clunk, though Maybe its not just one thing, but two things wrong.

Does the spindle orient correctly? If there were a spindle encoder fault or bad belt/coupling that would make the feedback bad, it could be a clunk due to motor shock as it is given a jolt to get it up to speed, then it overshoots, etc, kind of like a servo would behave when there is excessive mechanical backlash. Just a WAG

[M2_CNC]

I was a service/apps engineer for 8 years for a Haas Distrubutor here in Canada and im a Machinist/Millwright by trade. The clunking you are feeling is the coupling between the top of the drawbar and the spindle motor. It has either come loose or the key is worn. I do have detailed drawings of this if needed let me know

Mike

[ARB]

Originally Posted by M2_CNC

I was a service/apps engineer for 8 years for a Haas Distrubutor here in Canada and im a Machinist/Millwright by trade. The clunking you are feeling is the coupling between the top of the drawbar and the spindle motor. It has either come loose or the key is worn. I do have detailed drawings of this if needed let me know

Mike

Hey Mike. Welcome to the community. An old pro like yourself will be welcome around here.

Pull up a chair and stay a while.

ARB

[M2_CNC]

Fire away with any questions i will try to help you all out if i can . As i am no longer working for the Haas /Okuma dealer here in Canada i have started my own buisness. M2 CNC Repair and Maintenance it has been going very well.