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View Full Version : Need Help! Deep Hole Drilling



Tornos100
06-18-2010, 02:54 PM
Has anyone had any success with drilling small holes on a Citizen L20. I am trying to drill an .018 dia. hole 1 inch deep in titanium. I am using a high speed chuck(nsk) but I am having trouble with the drills breaking. I am drilling450 deep with a shorter drill, then trying to finish the hole with the (nsk) high speed chuck. Any help would be greatly appreciated.
THANKS

cogsman1
06-19-2010, 09:46 AM
Have done deeper than that in 6al4v. What are your settings? Speed? Peck Depth? Retract setting? What Spot drill, tip dia?

Tornos100
06-21-2010, 08:17 AM
Thanks for getting back to me.
I am using a #o centerdrill
The first drill(.018 short) settings: S1=9500
G83 Z.450 Q.003 F.0002 R0

The second drill (.018) settings: M158 S8500 (NSK)
S1=4500
G0 Z-.015 T23
G1 Z.430 F.0003
G1 Z.448 F.0001
G0 Z-.01
Z.401
G1 Z.443 F.0003
G1 Z.451 F.0001
G0 Z-.01
Z.404
G1 Z.446 F.0003
G1 Z.454 F.0001 (Doing this pattern to a depth of .650 right now)

danrudolph
06-21-2010, 12:01 PM
going from a .003 peck on the short drill to an .008 peck on the long drill. i'd do it the other way around. maybe even dwell at z-.01 for a bit to cool the long drill off.

also, #0 center drill is probably a poor choice opposed to a spot drill. learned that the hard way a few weeks ago. mitsubishi has a interesting looking spoting drill for microdrills, but it's on backorder until september. their ad for it shows exactly the condition we were creating using a #0. picked up a harvey tool spot drill instead, worked like a charm.

cogsman1
06-21-2010, 12:22 PM
You must use a spot drill that is sharp enough at the point to direct the drill into the true center. Mitsubishi's "Drill Starter" is the best I have used for this. I have also used a single flute counter sink when I could not get the drill starter.

g-code_junkie
06-23-2010, 12:52 PM
I have also used the Severance carbide multi flute countersinks 4Y-W-DE 22249.

cogsman1
06-24-2010, 06:57 AM
Thanks! that tool looks like a good choice also. Always looking for more choices.

shrektaylor
07-05-2010, 06:31 PM
try slowing down your spindle, you may be spinning too fast to cut depending on what your drill is made of, carbide cobalt hss ect. if you spin to fast you will cause a carbide drill to chatter or bounce at the bottom of the hole, carbide is brittle this scenario would cause you to snap your drills, hss or cobalt you would burn your tools also causing work hardening, this would be my first step. i have a hs chuck but have yet to use it for drilling it simply doesnt like it. try 2000 rpm and go from there. i would also write your deep hole cycle in g83 allowing your drill to come all the way out allowing it to cool and chip removal from the hole. my personal preference is titex carbide through coolant have had very good results. you may also try counter rotation with a rotary tool. if you choose a good quality carbide through coolant drill you should not have to peck, allow the coolant to romove your chips and heat eg; on my m32
t2200;
g97 s1=1500 m3;
b2; (high pressure through turret)
go z-.05 t22;
g1 z-.005 f.03;
z2.757 f.0025;
g4u.01;
g0 z-.1 t0;
b2;
g28u1;
t2000;

MetalZilla
02-27-2013, 04:57 PM
Hi,
try this Drill Pecking Calculator: Drill Peck Calculator (http://www.webmachinist.net/drillpeckcalculator.html)