O/T Twist Drills for Tough Holes

[chris m]

I'm looking for some help on a tough hole we're drilling with very poor drill performance.

 

I'm drilling .106 diameter holes 1.100 deep in Nitronic 60 material in a VMC, no coolant through, no high pressure and I'm not having much luck. I've tried higher feeds, lower feeds, big pecks, small pecks, drilling with one drill, drilling the top of the hole with a screw machine drill and then using the jobber, etc, all without a reasonable result.

 

1) Does anyone else regularly machine Nitronic 60? I'd like to compare notes on all types of machining if you do.

 

2) Whose drills are you guys using for tough materials and/or deep holes? I've got a 'special' cobalt parabolic drill coming in from Guhring to try but I don't want all of my eggs in one basket.

 

Any help would be appreciated, thanks.

 

C

[McRae]

Chris

 

10 times "D" on a vertical, no coolant thru, in Nitornic 60...

 

Wow -

 

I would have put this thing on the gundrill for those parameters and then fixtured the hell out of it so that the positions between holes went smooth.

 

However - you mention that you have Guring on the case so there is nothing else I can add other than a little hope and a lot of admiration.

 

Guring will get the job done, (they are my first and last choice for drilling dificulties) their only limiting factor may be stock... Order lots of drills.

[Kevin Goddard]

We regularly drill nitronic 60 with success but we use coolant thru a Mitsubishi MZS drill with high pressure (well, what Haas calls high pressure). Depths are 5X. I know this does not help your case, but for us I believe the thru coolant and the Mitsubishi is the key. We use the MZS in 718 Inconel, Nitronic 60 & 70, 17-4. 10X that small in Nitronic WITHOUT thru coolant is gonna be fun. Good luck and keep us posted.

[CAM-mando]

Its not pretty, but would you consider a coolant ring adapter ?

[Harryman]

Hi Chris.

 

In a standard jobber style twist drill (for stainless steel) we really like Norsman Drill & Tool St Paul, Mn Super Premium black & gold.

 

Harryman plugging the locals

[fboike]

Chris,

 

I have a similar job (sept I have to ream it to)that I run alot.

I use a solid carbide drill #37 drill @1800 rpm

1.8 ipm peck .02 and flood the coolant straight

down the hole. its better with through the spindle but I dont have it.

[Hardmill]

Look at guhring drills.

They got drills for all applications.

 

PEACE

[chris m]

Thanks for all the input guys; I'm going to try out one of Guhring's new products and let you know what she does

 

C

[kccadcam]

quote:

---

We regularly drill nitronic 60 with success but we use coolant thru a Mitsubishi MZS drill with high pressure

---

+1 on that

 

Chris, the MZE Mitsubishi drills are the same as MZS without the coolant holes. Their new VP15TF coating rocks! They are every bit as good as Guhring and less money.

 

JMHO

[chris m]

OK

 

status update on this

 

Guhring F5522-2.700MM (.1063) Firex coated parabolic cobalt jobber drill

 

45SFM (1617 RPM), .003IPR, .030 Peck, Z.200 R plane, 1.060 deep

 

Successful with around 150 holes on the drill before it looked sad enough to yank it. No breakage at all during testing although I hammered the Feed Hold a couple of times with some other parameters I was trying.

 

Not too bad when my other drills wouldn't make one hole.

 

Guhring guy says he's coming in to talk about other options (42 pecks per hole X 8 holes per part ain't setting any speed records) but making parts slowly is better than not making them at all.

 

C

[robk]

Glad to hear Guhring worked for you... They really are excellent drills especially with the firex coating. I'm in the process of switching over to Guhring from Mitsubishi, not because the Mits. drills are inferior in any way but the size range from Guhring is really an advantage especially for its lengths.

 

Rob

[Harryman]

On super nasty materials, sometimes success can be defined as the one method that didn't fail.

 

150 hole drill life doesn't sound too bad. In fact, to go faster say 50 - 55 SFM and sacrifice some hole count, might be an option. The speed, feed and peck parameters seem OK for such a small drill going so deep. I'd be happy with those results, but then I'm not a production guy.

[Hardmill]

Outstanding Chris.

Those drills never cease to amaze me.

 

PEACE

[McRae]

Thanks for the status update. What is the peck depth that you are running? 48 times perhole sounds like a nice short chip length - is the retract all the way out or do you use an internal break only cycle?

 

Nitronic - ever weld overlay that stuff for wear resistance?? Would love to talk offline if you have.

[chris m]

Never did that Andrew, sorry.

 

G83 Z-1.0581 R.200 Q.032 F4.9 M53

 

Larger pecks = smoked drill .800 deep 1st hole

 

G73 = smoked drill .500 deep 1st hole

 

C

[Jack Mitchell]

Super question and super advise as well.

 

Thanks Chris for the summary update - so many other questions come bye and we never hear from the originator again.

 

Would you have any input on the current Integrex eia synchronous tapping/restart question?

I'll work with this tomorrow but alas it's not an Integrex so the effort might not necessarily help with solving this problem.

 

Does your machine have an encoder adjacent to the spindle for sync?

 

 

Regards, Jack

[chris m]

No help on the Integrex, Jack, I've been reading Harryman's thread to learn from you guys that are more Mazak savvy, though. My Integrex has entered "don't ask, don't tell" territory; the only guys talking about that thing now have 'Esq.' on their office doors

 

C

[TheePres]

Anyone use these Gurhing drills on titanium??

Would like to hear any advice on drilling this stuff.

[chris m]

TheePres

 

We don't do any Ti here, so I can't really help directly but I strongly suggest calling (800) 877-7202 and talking to Guhring directly. They are very helpful and will be happy to suggest the drill and cutting parameters that they feel are best for your application. There are a lot of new tools in their arsenal that aren't in the old catalog and they have some new coating options that aren't even in the new book.

 

Also, make sure you get a copy of the new 2003 catalog [grey cover vs. old black/brown cover] as there are new toys in there.

 

C

[crazy^millman]

I would use a good cobalt drill with a parbolic twist. I try to say at about 32 to 45 sfm with them. Keeping my chip load per tooth anywhere from .002 to .005 depending how deep I have to drill the hole. I would peck at anywhere from .05 to .15 to allow for cooling of the drill and kick my rapid down when doing it also doing a complete retract if youy dont have a thru the spindle coolant on the machine. If you have it then should have smooth sailing.

 

Crazy Millman