[rosco]

Hi guys,

Can anyone give help on cutting a 4" hole, 10 inches through Inconel. I need feeds, speeds, cutters. I have 32 of these to do. Any help would be great. I am cutting on a horizontal boering mill with 25hp.

Thanks,

Matt

[Cruiser]

Matt, Inconel is one of the most tenacious matr'l you can machine. The harder you push on it the harder it pushes back at you. If you try to go too far with a marginal tool then it will take out the tool and work harden a surface that you may not be able to get through easily to finish the hole. For this reason I am going to suggest that you contact your salesman and get the best tooling possible for punching the holes. I've done carbide roughing on inc castings that req'd a surface speed as low as 65/85 and a moderate feed, but, I had to listen to and watch it closely and as soon as I felt the tool go away retract and play the inconel game of chase the tool. I am not going to get specific, because it is all pertinent to your tooling, and setup. We would often have the salesman come in and go through the process so they could help prove their tooling worthy and if it failed, they would take the tooling stubs back with them ! The best and fastest cutting when it can be used is ceramics.
Get the best tool possible !

[Delw]

718 is the easiest to drill. we always used kemetal insert drills max dia of 1.750"on inco.
Then roughed out with a 1/2 round ceramic boring bar roughing at an angle and stepping the angle so it didnt break the insert on entry. We found it faster to use insert drills no bigger than 1.75 as we had problems with larger ones, then roughing. But that was just us. this was also back in the late 80s early 90s and I am sure they have improved insert drills for ceramics sence then.

Delw

[djohn]

Hi Matt,
Try Walter inserts. Website of Walter AG: Cutting tools milling, drilling, turning and threading

I had never heard of them until I had a job eat my shops lunch for two months. I finally relented, after trying all of the popular name brands and ALL of their tool reps leaving with tails tucked.

I don't remember the grade and such but we were able to run numbers equal to cutting stainless 303. We were amazed, it was also about a 4" hole about 12" deep. We babies a spade drill through it for a pilot and ran a 1.5" boring bar at approximate .012 and between 150-180 SFM and took the prize.

The next fastest way was EDM wire which worked great but took 24 hrs to make the circle.

HTH
Dennis