I was rough milling removing T6061 aluminum with a 1/2 inch end mill and the R8 draw worked loost. I did not discover it for a couple of minutes. When I redrew the draw things seemed to work correctly. How can I determine if I did any damage?
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R8 collet worked loose during milling - how can I tell if I did damage?
- Thread starter dansawyer
- Start date
- Joined
- Apr 26, 2014
- Messages
- 242
An easy test would be to measure TIR with a dowel pin or clean end mill in the collet. Measure TIR with the collet/end mill holder that worked loose, and if that is off by more than a thou or two, try a different collet.
- Joined
- Dec 20, 2012
- Messages
- 9,422
The real issue is ... did you damage the internal spindle taper? If you did not then no problem; if you did then big problem. So, how do you tell?
Use a flashlight and a mirror and look up into the spindle taper to see if there is any obvious signs of damage. You have to look at the taper near the end of the spindle but also try to see the upper ground section. If you don't see anything then move on to checking the spindle concentricity. If you do see damage then you're looking at a spindle change.
Assuming no obvious spindle damage, mount a DTI in a rigid indicator holder; ideally, you want the two-arm type that is much more rigid than the common single-knob Noga-type holder but use what you got. Remove the belt from your pulley so the spindle can free wheel, then bring the DTI tip into gentle contact with the spindle and preload the arm so there is about 0.015" of load and zero the dial. Place a Sharpie mark on the quill and the spindle nose so they align, then slowly turn the pulley up top and make a complete revolution, aligning your Sharpie marks again. If the DTI reads zero then your set up is rigid and reliable enough to use for this evaluation. If it does not return to zero then you need to improve the rigidity of your set up.
Now make one revolution by turning the pulley and note the deviation of the DTI. There will typically be a high and low reading; your TIR is the high minus the low. Write it down. Also mark the spindle where these deviations occur. Now repeat this process half way up into the spindle taper and see if the deviations are in the same place and of the same magnitude. Repeat this further in, up near the end of the outer taper and see if the deviations are consistent. If all the deviations are in the same place and of similar magnitude then chances are you did no real damage to the spindle. You also now know the TIR of your spindle.
Use a flashlight and a mirror and look up into the spindle taper to see if there is any obvious signs of damage. You have to look at the taper near the end of the spindle but also try to see the upper ground section. If you don't see anything then move on to checking the spindle concentricity. If you do see damage then you're looking at a spindle change.
Assuming no obvious spindle damage, mount a DTI in a rigid indicator holder; ideally, you want the two-arm type that is much more rigid than the common single-knob Noga-type holder but use what you got. Remove the belt from your pulley so the spindle can free wheel, then bring the DTI tip into gentle contact with the spindle and preload the arm so there is about 0.015" of load and zero the dial. Place a Sharpie mark on the quill and the spindle nose so they align, then slowly turn the pulley up top and make a complete revolution, aligning your Sharpie marks again. If the DTI reads zero then your set up is rigid and reliable enough to use for this evaluation. If it does not return to zero then you need to improve the rigidity of your set up.
Now make one revolution by turning the pulley and note the deviation of the DTI. There will typically be a high and low reading; your TIR is the high minus the low. Write it down. Also mark the spindle where these deviations occur. Now repeat this process half way up into the spindle taper and see if the deviations are in the same place and of the same magnitude. Repeat this further in, up near the end of the outer taper and see if the deviations are consistent. If all the deviations are in the same place and of similar magnitude then chances are you did no real damage to the spindle. You also now know the TIR of your spindle.
2 tests.
With a Sharpie or other similar marker, fully paint the taper and sliding areas of the collet that did this and a like new collet.
Rotate head 90 degrees so you can easily see inside.
Inspect first just to look.
Insert new tool in collet and install then remove, do both, cleaning spindle after each.
Examine both collet and spindle for ink transfer and removal.
This will help show differences or damages.
Sent from my SAMSUNG-SM-G930A using Tapatalk
With a Sharpie or other similar marker, fully paint the taper and sliding areas of the collet that did this and a like new collet.
Rotate head 90 degrees so you can easily see inside.
Inspect first just to look.
Insert new tool in collet and install then remove, do both, cleaning spindle after each.
Examine both collet and spindle for ink transfer and removal.
This will help show differences or damages.
Sent from my SAMSUNG-SM-G930A using Tapatalk