[How do I?] Tips on Boring with 4 jaw

[Mheaton92]

Hi everyone, I needed to bore a 1.476 flat bottom hole in some 6061. I was going to use the boring head but thought the lathe would be easier. I indicated it in the 4 jaw and started. I got it all done but the surface finish inside the hole is not very nice. I wasn’t able to turn my speed up because the hole was eccentric. After 400 rpm my whole lathe would shake (I have a pm1030 on a steel stand I built). If I made my stand a significant bit heavier would that help?


Sent from my iPhone using Tapatalk

 

[benmychree]

I suspect that the problem lies with the boring tool and lubricant, you just need to run slower to eliminate the shake.

 

[mmcmdl]

Use a counter balance if possible .

 

[RJSakowski]

Check to make sure the heel of the boring bar isn't dragging on the cut. This is more of a problem with small bores but not inconceivable with a larger bore. Rotate the tool or adjusr the height if not possible to rotate. I will typically grind down the heel of my boring bars to provide clearance.

 

[Mheaton92]

I suspect that the problem lies with the boring tool and lubricant, you just need to run slower to eliminate the shake.

That is what I did, what I was asking was about the surface finish from running aluminum slow? I’m not even sure if that is a thing. That makes sense it was the boring bar rubbing somewhere, thank you.


Sent from my iPhone using Tapatalk

 

[Mheaton92]

Check to make sure the heel of the boring bar isn't dragging on the cut. This is more of a problem with small bores but not inconceivable with a larger bore. Rotate the tool or adjusr the height if not possible to rotate. I will typically grind down the heel of my boring bars to provide clearance.

Thank you, I will have to try it.


Sent from my iPhone using Tapatalk