Evan LaCava
Cast Iron
- Joined
- Jun 25, 2013
- Location
- NYC
So I thought I had this job all planned out ready to bang out. nope.
two broken inserts on a boring bar i ordered just for this job. Tiny guy.
Part is an aerospace bolt, 1.09 deep bore .312dia flat bottom.
Thought I had this, I drilled 19/64" dia hole with the drill bit tip hitting the 1.09 bore depth.
Then used a 4 flute endmill that I basically ground away all cutting edges except the front face. Reduced the diameter just a hair (this where I went wrong? there is a reason for me reducing the dia but I won't get into it now)and used that to produce the flat bottom.
Then used a tiny indexable boring bar I just bought(I broke the last one I had, and needed a new one for an upcoming job that has a .300" bore dia on it)specifically to run this job. That inside needs a .005-0.015 radius....so I wanted an indexable tool that used inserts with a TNR in between there to avoid having to move the boring bar down in the radius cutting, and possibly contacting on the opposite side of the cutting edge.
'
Anywayyyy...I tried different programming but the insert snapped twice! that step is measuring 1.080" deep, so that has to be where the insert is snapping... .010" shy of the endmill "bored" depth.
Any suggestions? I see there is a $153 flat bottomed drill bit at MSC....ehh...I'd rather not waste more $ on this job I'm not making much at this point as it is, and I'm not even sure that would solve my problem.
And i know there is a slight "taper" to the endmill face, hence that showing up in my part...but its a wide open tolerance bored depth, so the part will pass inspection without issue....the inspector just doesn't want to see a drill point or step in there.
Machine is a Mori SL1a. No Live tooling.
two broken inserts on a boring bar i ordered just for this job. Tiny guy.
Part is an aerospace bolt, 1.09 deep bore .312dia flat bottom.
Thought I had this, I drilled 19/64" dia hole with the drill bit tip hitting the 1.09 bore depth.
Then used a 4 flute endmill that I basically ground away all cutting edges except the front face. Reduced the diameter just a hair (this where I went wrong? there is a reason for me reducing the dia but I won't get into it now)and used that to produce the flat bottom.
Then used a tiny indexable boring bar I just bought(I broke the last one I had, and needed a new one for an upcoming job that has a .300" bore dia on it)specifically to run this job. That inside needs a .005-0.015 radius....so I wanted an indexable tool that used inserts with a TNR in between there to avoid having to move the boring bar down in the radius cutting, and possibly contacting on the opposite side of the cutting edge.
'
Anywayyyy...I tried different programming but the insert snapped twice! that step is measuring 1.080" deep, so that has to be where the insert is snapping... .010" shy of the endmill "bored" depth.
Any suggestions? I see there is a $153 flat bottomed drill bit at MSC....ehh...I'd rather not waste more $ on this job I'm not making much at this point as it is, and I'm not even sure that would solve my problem.
And i know there is a slight "taper" to the endmill face, hence that showing up in my part...but its a wide open tolerance bored depth, so the part will pass inspection without issue....the inspector just doesn't want to see a drill point or step in there.
Machine is a Mori SL1a. No Live tooling.