Weird noise with 1/2 inch straight "O" flute bit

[Optics1942]

Hi,
I have the ShopBot Desktop with the spindle. Using the 1/8th inch and 1/4 inch bits seem to work fine, but when I put the 1/2 inch bit in it sounds like a very loud rattling noise at a certain frequency. I know the bit will resonate differently at different frequencies, but this doesn't sound like a change in resonance it sounds like something is rattling around or broken.

https://goo.gl/photos/KVNBx6pUiRB3mU2e7

Has this ever happened to anyone, or does anyone know what it wrong?

[knight_toolworks]

I have had vibes with that bit too got them cheap and now I know why. it think it is just a imbalance from the design.

[EricSchimel]

Have you checked the runout on the spindle? I just had my spindle go due to a worn bearing....

[knight_toolworks]

I had this on my new spindle though it was worse on the worn one.

[Martin Reid]

Dear Optics1942

Try this for me please...

(1) New collet & same bit = same or better
Same.. looking like the bit is out of balance whoo!

(2) New (similar) bit & original collet = same or better
same.. could be the collet is knackered you will know how much use it has had! - I change ours a couple of times a year - You may see 'grey' shadow marks on the cutter shaft where the collet is 'vibrating'

(3) New collet & new (similar) bit = same or better
Same.. big problem probably the bearing

I'm watching the post with interest

Sincerely and in good faith
Martin

[Martin Reid]

Dear Optics1942

I posted a response this morning; a moderator must have taken exception to it as has not appeared here yet. I will look at it again when I get home from work.

Sorry for the delay
Martin Reid

[Optics1942]

I have had vibes with that bit too got them cheap and now I know why. it think it is just a imbalance from the design.

I use the onsrud bits, what did you have?

Have you checked the runout on the spindle? I just had my spindle go due to a worn bearing....

yeah, 0.0002". The spindle is as old as the machine (3 years), I was worried it might be the spindle. Did you have the same problem with different sized bits you were using?

Dear Optics1942

I posted a response this morning; a moderator must have taken exception to it as has not appeared here yet. I will look at it again when I get home from work.

Sorry for the delay
Martin Reid

Okay thanks

[scottp55]

Alison,
Are you using good quality collets/collet nut?
You may want to check all your nuts/bolts for tightness...I had X-rails loosen up at about 2 years, and other bolts as well.
When was last time you checked?
I'm a little worried about spindle also....but our 2 Desktops are almost a year older than yours, and with almost religious warm up routines and virtually never doing straight plunges...ours are still humming along nicely(knock on wood).

(Martin...there's been a glitch where the software sets some replies aside for the Moderator to approve for no good reason...and Mod has to go and unlock them....BUT the Mod never even gets notified that the reply is frozen I thought it was fixed) Maybe try again...it was really hit or miss random.

[Optics1942]

Alison,
Are you using good quality collets/collet nut?
You may want to check all your nuts/bolts for tightness...I had X-rails loosen up at about 2 years, and other bolts as well.
When was last time you checked?
I'm a little worried about spindle also....but our 2 Desktops are almost a year older than yours, and with almost religious warm up routines and virtually never doing straight plunges...ours are still humming along nicely(knock on wood).

(Martin...there's been a glitch where the software sets some replies aside for the Moderator to approve for no good reason...and Mod has to go and unlock them....BUT the Mod never even gets notified that the reply is frozen I thought it was fixed) Maybe try again...it was really hit or miss random.

The first thing I did was go through and check all of the nuts, bolts, and screws. They are all tight. I am using the collet and collet nut you can buy directly from the shopbot website.

[scottp55]

And you say it that noise isn't there with smaller bits?
I run 1/2" shank bits all the time, and can't tell the difference from spindle noise.
Did it Just start happening? Or has there been a gradual increase in spindle noise?
Have you had an accidental "catastrophe" (Like drilling/cutting with your collet nut, or a major plunge mistake recently)?

Is the noise the same at all Z heights, or only when near Z topping out?
I'm running out of ideas
scott