17-4 stainless 5

[punches]

hello
need help on what kind of drill to use for drilling 17-4 stainless steel in the soft condition.
also what speeds and feeds to use.
.600 deep with .386 dia. drill with no coolant holes-will be bore after drilling.
machined on newer mazak lathe.
thanks in advance

 

[z2000]

use cobalt drill.

personally i like titex drils but at least in israel the are very expensive.

 

[mrainey]

A reasonable starting point, using a high speed steel twist drill, would be 400 RPM at .005 IPR feedrate.

Manufacturing Freeware and Shareware

http://mrainey.freeservers.com

 

[z2000]

you suggest cutting speed of aprox. 12 m/s. with cobalt drills you can work with more than double speed.

 

[Philrock]

When machining 17-4PH, you must be very careful not to let the work get too hot. If it gets too hot, it will harden and become MUCH more difficult to machine.

 

[z2000]

this is why you must drill it at once.

ih this diameter you can drill with no fear.

 

[scottmaha]

Hi punches,

I have had success in drilling 17-4 with the following drill from Guhring:

Series #329

Guhring has a .3858"(letter "W") in their book. It has 1.7" of flute length which will be fine for your hole depth. Start out at 450 rpm with a feed of 2.3 ipm. Do not use the pecking cycle as this may contribute to work hardening of the material.

You will be fine with this drill.

 

[musashi99]

HHS drills work fine in 17-4. If you are drilling alot of holes cobalt will be fine as well.
I work in the sensor industry where 17-4 is a standard material. My company uses about 60-70 tons of 17-4 each year.

As far as speeds for HHS drill I use this little formula 191/drill dia. this works very well.
Sorry to disagree with oithers here but pecking drill 17-4 is not usually a problem you need to break those chips particularly on deep holes. Do flood the area with coolant.

 

[segges]

Strange as it sounds, but cobalt or HSS seems to work very well, as long as they are the black oxide coated ones. I have had no luck with the standard M42 or the bright finish HSS.

 

[unclesyd]

Here is a Gurhring description off a packet of drill bits we used to drill heat treated 17/4, 455,and 316 SS.
We used the same type bit up to 8 mm and probably a little larger. This manufacturing group stayed with Gurhring for all their drilling operation involving the PH alloys.

Art. No. 658 K
DIN 338 RN
S-Bohrer GT1
f 3.28 mm
HSCO EDBB **

These are used for blind holes 22mm to 30 mm deep in hardened PH alloys.
These are used on highly automated (Burgomaster) drill presses running 24/7/365. These drill bits are TiN (golden) and are resharpened and recoated several times.
I think this particular drill bit has been replaced lately with another style Gurhring in the same family, but this type was used for many years.

I thought I could give you some idea of the feeds and speed but I’m having trouble getting the time of day from the people presently in charge of this operation.

 

[aamoroso]

TiN Coated 135 degree point (split point helps). You can drill forever without a problem.

Fill what's empty. Empty what's full. And scratch where it itches.

 

[christate]

OSG has line of drills made just for stainless. They are second to none. I have drilled stainless for 13 years and these are the best. I think they are called EX-Gold series.

 

[musashi99]

You want 135 deg. drill point geometery rather than the standard 118 deg.