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Tool Cx707 4jaws chuck vibration

Tool
T

Theflyingwrench

Active Member
Hey all, my 707 is running great since I setup about 4 months ago. The 4 jaw chuck had a bad vibration in it when I set it up. So I sent it back and under warranty busy bee sent another that was said to be tested before sending. This one shakes the machine as bad. Up to 500 rpm it's not really noticeable but after that it's bad. Concerned about bearing damage and chatter in parts if I used it. Has anyone else had this trouble with the supplied San ou 4 jaw? 3 jaw ans naked spindle are vibration free at all speeds. Is there a way to fix this without a dynamic balance?
 
These are standard Chinese chucks everyone uses.

Do you have a part in the chuck? Is the part centered? If not, are the jaws all evenly in? Did you put dial indicator on chuck body? What is the runout?

Also the machine may be reaching a harmonic vibration with this load at around 500 rpm, if you go faster is it gone?

500 rpm is not fast at all.
 
Ya, it's called a "dynamic balance". Lol!

4 jaw chucks are usually bigger, heavier, and less well balanced than 3 jaw chucks. That's just the way it is. But you can improve the situation with a little effort and some patience.

Remove the Jaws and set them aside, start putting sticky weights on it, spin it up, move the weights, watch what happens, add weight, remove weight, move weight, and find what is needed where. It isn't really that hard to do. Just takes patience.

Remember that the jaws and parts can throw it way off balance afterward. So you are trying to balance it without them. But you have to accept that it can't always have good balance - it just the nature of a 4 jaw to be a bit unbalanced in use.

I'd prolly also look at what else might be magnifying the unbalance. Poor feet, spindly legs, etc. You won't see it without the chuck to start the resonance. But it's still there waiting for the push.
 
Hi Tom,
Just a pin centered in the chuck
1000008393.jpg

The Runout on the od is about 0.001".
The face has about.0.0002" runout.
I agree that 500 rpm is not fast but anything above that and it shakes the lamp, tools on the top of the lathe, the entire head stock etc... it's all bolted to the concrete too.
 

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Remove the jaws and check whatever it still does it - this is VERY strange, I mean I have like multiple Chinese 4 jaws on both of my lathes and none do this.

Yes, the 4 jaw can be ... less balanced but not to this degree.

Did you try to put some larger piece of metal in your 3 jaw to simulate 4 jaw weight? I want to eliminate the machine.

Also if you have a friend with same D1-4 spindle, ask him to check the chuck for you.
 
Tom Kitta said:
Remove the jaws and check whatever it still does it - this is VERY strange, I mean I have like multiple Chinese 4 jaws on both of my lathes and none do this.

Yes, the 4 jaw can be ... less balanced but not to this degree.

Did you try to put some larger piece of metal in your 3 jaw to simulate 4 jaw weight? I want to eliminate the machine.

Also if you have a friend with same D1-4 spindle, ask him to check the chuck for you.
Click to expand...
Swaping with a friend is a good idea! For the chucks I mean. I'll start asking tomorrow..
As for something heave in the 3 jaw I have a piece of 1 3/4" about 6 inches long. It won't fit through the bore so I live centered it. I'll put something big in it tomorrow.
Thanks for the help !!
 
You could do the process of elimination, run the chuck without jaws, then without the jaws and pinions then if it still vibrates at least now it's narrowed down to the chuck body.

Where are you located?
 
Bolted to the concrete has issues as you can add stresses to the bed and headstock. The rubber machinery feet still allow for leveling but ensure the random vibrations are absorbed instead of reflected back into the machine.

Second thing is a 4 jaw typically allows you to center accurately or offset intentional. The first should be vibration free and the second well it is what it is, in most cases I've found you limit you rpm to ensure not excessive vibration are added to the machine.
 
Theflyingwrench said:
Swaping with a friend is a good idea! For the chucks I mean. I'll start asking tomorrow..
Click to expand...

Now THAT was funny!

Finding someone in Newfoundland to swap chucks with might be a challenge though. Consider lining something up with someone in Nova Scotia too. I know it's a lot further than most would think, but when you are in need, it's worth the extra effort.

I second @PeterT s suggestion to read the other thread. That's what was in my mind when I suggested balancing it yourself. But I couldn't find the thread.
 
Any chance your spindle is not tight on the bearings? I eliminated spindle vibration once when I noticed the nut that holds the spindle tight was loose.
 
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