Looking for feedback on my mill spindle runout

[ltlvt]

Checking the spindle runout on my Bridgeport clone. It clearly has about .001 run out at low RPM's. Sometimes the needle will come to a complete stand still when the revs are increased. is this just a matter of "The Hand is faster than the Eye" I have yet to make any chips on the mill. Maybe tomorrow I will install and tram a vice and see what it does under load. I am looking for feedback. I have also taken the collet and dowel pin out and indicated the inside of the spindle on the taper and still have the same .001 run out yet I cannot see or feel anything inside of the R-8 spindle.

 

[sdelivery]

Enjoy your mill, when you see how it cuts then you can worry about run out.
Many things can affect your indicators reading.
After tramming Cut some metal!
Don't get into the pick it apart over some indicator readings, after doing a little cutting you will find out if you can cut to size and if you can get a reasonable surface finish.....unless of course you are making space shuttle parts.

 

[jwmelvin]

To me, that looks like you’re seeing the low-pass of the indicator, which cannot respond to high frequencies because of inertia.

The behavior as speed ramps up seems pretty consistent, just eventually drops off as the indicator mechanism can’t keep up.

I’ll agree with the response above, to a degree. My BP clone has more runout than that but works fine for me. It will no doubt affect tool life and finish. At some point I’ll likely try to address it.

 

[RaisedByWolves]

I've been a toolmaker for 37yrs and have never even considered spindle runout nor has it ever concerned me.

What you're measuring is not in fact even spindle runout, but a combination of spindle, collet and pin runout.

To show this, take your pin and find the high spot by hand, turning the spindle by hand that is. Mark this spot on your pin. Then remove the pin and collet and randomly reinsert them and re indicate.

Your high spot had now most likely moved. Or it may have disappeared. Or it may have increased in size.

You can often hear an endmill cutting biased to one flute, which as mentioned above will effect finish to a degree, but tool life likely wont be affected as you're not likely to line up the endmill the same way every time you insert it unless using endmill holders exclusively.

And don't take this the wrong way, but you're likely way outside of that indicators ability to accurately perform this job.

 

[ltlvt]

I've been a toolmaker for 37yrs and have never even considered spindle runout nor has it ever concerned me.

What you're measuring is not in fact even spindle runout, but a combination of spindle, collet and pin runout.

To show this, take your pin and find the high spot by hand, turning the spindle by hand that is. Mark this spot on your pin. Then remove the pin and collet and randomly reinsert them and re indicate.

Your high spot had now most likely moved. Or it may have disappeared. Or it may have increased in size.

You can often hear an endmill cutting biased to one flute, which as mentioned above will effect finish to a degree, but tool life likely wont be affected as you're not likely to line up the endmill the same way every time you insert it unless using endmill holders exclusively.

And don't take this the wrong way, but you're likely way outside of that indicators ability to accurately perform this job.

No offense taken. I have measured it without the collet or pin installed by putting indicator on the inside of the spindle and also the outside of the spindle with the same results. What dawned on me as I was going to sleep last night is the spring return inside the indicator is not capable f responding at the high RPM. I also used a Starrett Last word indicator and got the same results. I also blued the inside of the spindle taper and put the collet back in and it has a slight mark on one side, but I still cannot find any burrs or interruptions. Thanks for the feedback.

 

[ltlvt]

Enjoy your mill, when you see how it cuts then you can worry about run out.
Many things can affect your indicators reading.
After tramming Cut some metal!
Don't get into the pick it apart over some indicator readings, after doing a little cutting you will find out if you can cut to size and if you can get a reasonable surface finish.....unless of course you are making space shuttle parts.

I agree. Thanks for the feedback

 

[ltlvt]

To me, that looks like you’re seeing the low-pass of the indicator, which cannot respond to high frequencies because of inertia.

The behavior as speed ramps up seems pretty consistent, just eventually drops off as the indicator mechanism can’t keep up.

I’ll agree with the response above, to a degree. My BP clone has more runout than that but works fine for me. It will no doubt affect tool life and finish. At some point I’ll likely try to address it.

I agree. Thanks for the feedback.

 

[MrWhoopee]

It is a common theme among hobby machinists who have never worked in the trade to become obsessed with details that have no bearing on the ability of the machine to perform its intended task. It is quite possible to produce good parts on machines that are badly worn, working machinists are regularly expected to do so. Go make some parts and let us know if you have any problems.

 

[mmcmdl]

/\/\/\/\ . This sums it up . No one on here is making "space flight " parts for Nasa . Even if so , the machine doesn't make the parts , the operator does . Everyone worries about tenths .

 

[ltlvt]

It is a common theme among hobby machinists who have never worked in the trade to become obsessed with details that have no bearing on the ability of the machine to perform its intended task. It is quite possible to produce good parts on machines that are badly worn, working machinists are regularly expected to do so. Go make some parts and let us know if you have any problems.

I agree.