need help with this tough material

[Jmick]

We just got a job in that requires 1/4-20 tapped holes in a material called Tricon Dura Braze. This stuff is tough and rockwells @ about 42. We are burning up No.7 drills @ about 400 rpm. Haven't even tried tapping yet as I think we may try a thread mill. Any recomendations? Oh by the way we don't have through the spindle coolant. TIA!

[neurosis]

Thread milling sounds like a good idea.. how deep?

[Jmick]

.75

[Jmick]

thread mill brand for that small?

[Jmick]

single tooth or multiple tooth? helical flute?

[Jayson Kramer]

DO you have CTS (Coolant thru spindal) if so get a Mitsibuishi carbide drill. then thread hob the threads.

[Allan]

My first thought is wow 400RPM is that ever slow for a .201 drill. That is like 21SFM, what kind of feed rate? I think I can hear the sound of the cut from here. While I've never cut that particular brand of wear plate, I do not recall cutting speeds that slow. I would get a better drill. If the flood coolant is half decient get a solid carbide and do not peck.

I believe you will need to thread mill for sure, but you will have a hard time with finding a thread mill 3/16-20 with .75" LOC.

 

Allan

[Guest CNC Apps Guy 1]

He'll probably need a single profile threadmill to get that deep. No trouble though. Solid Carbide on the drill and you shoudl be home free. CJT is not too expensive and best of all, their speeds and feeds are great starting points.

[Guyinthedesert]

I'm not familiar with that material, but Rc42 I would drill slower than that, maybe 280 rpm (15 sfm) for a cobalt drill. Carbide would be the way to go if it's in the budget.

 

Threadmill is the way to go, but if you want to tap it, use an Exo VC-10 with moly-dee

[Buddy J]

+1 Molly dee

[Jmick]

Thanks for the info guys. I will give it a shot.