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

[Optics1942]

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

The same noise is not present with smaller bits. There is a very aggressive noise around 90 with the 1/2". We generally run 1/4" bits, and hadn't had to use it in months. Last time it was used it sounded fine, however there have been plunge mistakes since then (nothing within the month or so). When i changed the bit and collet to the 1/2" it was immediately evident that it was not right. The whole moving arm vibrates and shakes.

Noise is the same at all z heights, changes based on x/y coordinates a little.

[Brady Watson]

There is a very aggressive noise around 90 with the 1/2".

Assuming you mean "90" as indicated on the VFD LED read out, this translates to 90Hz, which equals 5,400 RPM. With a big 1/2" cutter in that little spindle, she's growling at you telling you that you're dogging her out. These spindles don't have ANY power for work under 8,000 (OK maybe for small diameter drilling) and about 12,000 RPM for routing.

You need to keep in mind that this is a router & not a milling machine with a motor wound and geared for low RPM work. Crank up the RPM - I would suggest at least 200Hz (12,000 RPM ) and try again. It puts a lot of stress on the motor windings when you ask it to do work below its rated speed, because it is drawing a lot of amps to keep spinning at the speed you set.

These spindles are designed to run all day between 12,000-18,000 RPM. Running below this range will put more stress on it. I can't imagine your cut quality is very good at 90Hz/5400 RPM, if that's what you meant.

-B

[Brady Watson]

Disregard my last post...I didn't see your video. :eek:

...and I can't delete/edit it because it is in never never land somehow?

Sounds like a bad tool or collet. Try another 1/2" bit like a v-bit or end mill - if it still does it, replace your collet & nut. They are both consumables and don't last forever.

-B

[knight_toolworks]

is this what the bit looks like?

http://www.talkshopbot.com/forum/attachment.php?attachmentid=30602&stc=1

[Burkhardt]

is this what the bit looks like?

Wow, was that bit made by the village blacksmith?

[knight_toolworks]

Wow, was that bit made by the village blacksmith?

even better onsrud (G)

[Optics1942]

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

1 same- measured runout and it was very small
2 same- changed collet today
3 same- when I run the spindle with no bit in (just collet and collet nut) it sounds fine. also sounds fine when I run with a smaller bit (1/8 or 1/4" single o flute)


Disregard my last post...I didn't see your video. :eek:

...and I can't delete/edit it because it is in never never land somehow?

Sounds like a bad tool or collet. Try another 1/2" bit like a v-bit or end mill - if it still does it, replace your collet & nut. They are both consumables and don't last forever.

-B
I got a new collet and new collet nut yesterday, and a new bit maybe a week ago. New collet and collet nut are both from shopbots online shop- didn't help


is this what the bit looks like?

http://www.talkshopbot.com/forum/attachment.php?attachmentid=30602&stc=1
no, it is a straight 0 not a straight v

[Martin Reid]

Optics1942

I'm back..

You must be getting very frustrated by now.

Before I go on, I would suggest you send the 'video' to shopbot technical. They have always been very helpful to us when we needed them (and quick). I would post the link to this thread; it may help with some of their questions. Outline the tests you have done, new collet, new collet nut etc.

As for now; If your router cutter 'shafts' look like the one posted by knight_toolworks then I would definitely put it down to an old 'worn' vibrating collet (that is classic vibration 'shadowing'). - You have changed the collet (& Nut) so this should be eliminated.

You did mention "however there have been plunge mistakes since then"! What were these exactly? Is it possible the whole spindle is not perfectly plumb in the machine or the bed not sat flat on all 4 feet. I'm looking for something that will cause even a small amount of vibration, which goes unnoticed with the small 'lightweight' cutters but is still vibrating the bearing which then becomes more apparent with the larger 'heavier' cutters.

I don't think it is normal wear and tear for a three year old spindle under normal use.

Looking forwards.. possibly... change the bearing or replace the spindle?

Check out beacon14 - had a bad experience - http://www.talkshopbot.com/forum/showthread.php?1715-Spindle-wear-amp-tear&highlight=replacement+bearing.

Anyway I'll keep watching to see what the guys at shopbot say

Sincerely and in good faith
Martin Reid

[srwtlc]

Chuck the bit up in a handheld router and run it at various speeds. Does it vibrate there also? Out of balance bit, excessive bit runout?