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DavidR8's shop shenanigans

Ya know...most of us are using VFD's to power our motors. You can have the VFD display current. So keep taking deeper cuts or faster feeds and watch the current usage increase. Keep going more until it approaches, say 80% of your FLA. (or whatever you feel comfortable with.)
 
I snugged up the bearing till the spindle was too tight to move by hand. Backed them off till it would turn.
Max depth of cut without chatter in aluminum is .005 :(
My South Bend would do .060 in 12L14 no problem.

After all of this work I am not a happy camper.
 
David_R8 said:
I snugged up the bearing till the spindle was too tight to move by hand. Backed them off till it would turn.
Max depth of cut without chatter in aluminum is .005 :(
My South Bend would do .060 in 12L14 no problem.

After all of this work I am not a happy camper.
Click to expand...
Are you sure it's the spindle?
 
Lots of things contribute to chatter David. How solid are all the parts of the toolpost? What is your tool stick out? What is your part stick out? Is the head tightened down? Is the lathe bolted down. What are you turning and how? Etc etc etc. Go slow and steady and eliminate variables one at a time. You will find it.
 
jcdammeyer said:
Are you sure it's the spindle?
Click to expand...
I'm almost 100% sure it is.
Susquatch said:
Lots of things contribute to chatter David. How solid are all the parts of the toolpost? What is your tool stick out? What is your part stick out? Is the head tightened down? Is the lathe bolted down. What are you turning and how? Etc etc etc. Go slow and steady and eliminate variables one at a time. You will find it.
Click to expand...
2" diameter aluminum, 2" stickout past the chuck.
Toolpost is rock solid. 1/2" shank tool, TCMT insert. maybe 3/4" stickout
Compound gib locked, cross slide gib locked.
Lathe is bolted to the stand, there is no rocking or movement in the stand.
 
David_R8 said:
I'm almost 100% sure it is.

2" diameter aluminum, 2" stickout past the chuck.
Toolpost is rock solid. 1/2" shank tool, TCMT insert. maybe 3/4" stickout
Compound gib locked, cross slide gib locked.
Lathe is bolted to the stand, there is no rocking or movement in the stand.
Click to expand...
tool height?
 
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YYCHM said:
Try a different tool.
Click to expand...
Tried that too. HSS is basically the same.
It's acting exactly like my Clausing did when I first got it. The headstock bearings were way loose and it chattered like crazy on even the lightest of cuts.
Snugged them up and all the chatter went away.
 
David_R8 said:
Max depth of cut without chatter in aluminum is .005 :(
Click to expand...
David_R8 said:
Tried that too. HSS is basically the same.
Click to expand...
wow. I can take .100 DOC in aluminum, until the motor stalls, but no chatter.

Put on the face plate and check axial and radial runout. Something isn't making sense to me.
Another check is to chuck up a piece of HRS, say 1.5" and put pressure on the bearings in all 4 directions and check for one direction being soft.

Lastly, check the seating of the headstock, and that the hold down bolts holding the headstock to the ways are very tight. 70% of yield tight. If they are at all not snug enough, you will get a lot of problems, including this one.

That's all I can think of right now.
 
I suppose you could try putting your hand on the headstock near the bearing and on the tool and feel which one is vibrating the most.

Same with headstock and bed. Tool and tool holder
Etc etc

Any chance you have an old style variable timing light? You can use that to watch vibrations. Chatter is a vibration. Need to find out what is vibrating.
 
Susquatch said:
I suppose you could try putting your hand on the headstock near the bearing and on the tool and feel which one is vibrating the most.

Same with headstock and bed. Tool and tool holder
Etc etc

Any chance you have an old style variable timing light? You can use that to watch vibrations. Chatter is a vibration. Need to find out what is vibrating.
Click to expand...
I do have one as a matter of fact.
 
Dabbler said:
wow. I can take .100 DOC in aluminum, until the motor stalls, but no chatter.

Put on the face plate and check axial and radial runout. Something isn't making sense to me.
Another check is to chuck up a piece of HRS, say 1.5" and put pressure on the bearings in all 4 directions and check for one direction being soft.

Lastly, check the seating of the headstock, and that the hold down bolts holding the headstock to the ways are very tight. 70% of yield tight. If they are at all not snug enough, you will get a lot of problems, including this one.

That's all I can think of right now.
Click to expand...
Thanks John.
I’ll have a look at those things tomorrow.
Trying not to assume the worst at the moment.
 
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