Breaking off rounded corners

[Kratos]

The inserts used turn the OD and Bore the ID always have a radius tip. Even if I program a perfect 90 degree angle the corner will always have a radius the size of my insert (either .031 or .015). On some applications I can’t have that small radius because the part needs to fit flush with another component and that small radius would be in the way. So I need a tool that can go in there and create a small dip to break off the rounded corner. The image I attached has an example of this. A lot of times it can be accomplished with a small grooving tool a .125 grooving tool is to big. Do any of you know of any tools I can use to achieve this? On OD I can usually get a away with a cutoff tool, but any suggestions for ID corners. Some parts have a bore depth of .125, so this tool would have to be way smaller. TIA!!

 

[706jim]

I recall seeing an Iscar video where they produced this sort of relief with one of their standard tools.

 

[tonymor]

We use DNMG tips to finish the OD. Just do an undercut 2x the tip radius.

1/2" RH MDJN Tri-Lock Tool Holder


Plenty of boring bars out there that you can do the same on the ID.

3/8" RH SDUCR Boring Bar For DCMT Inserts

 

[DouglasJRizzo]

I usually finish the contour and then head back in with a sharp nosed insert and gently relieve the back of the bore.

 

[Mtndew]

DNMG, VNMG etc..
Some mfg's make a dedicated tool that's kicked on a 45deg to do plunge style undercuts also.
But if it's just a corner relief, then use a VNMG tool to go in and scallop it out. There are standard RH and LH tools as well as some VNMG holders that are on like a 117deg or something.
Same goes for the ID bars.

 

[Booze Daily]

Google "45 degree undercut tool holder"
There's a bunch to choose from.

 

[mmurray70]

Cant chamfer the mating parts?

 

[Kratos]

Thank you all for the helpful advice! I found what I needed.