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View Full Version : How to drill T303 SS quickly?



gakor
02-21-2008, 01:38 AM
Hello again,

I need to drill on my Miyano Screw Machine .375" dia -0.000 / +0.002. Stainless Steel T303 0.625" deep. A nice, smooth, and shiny finish is required.
Can it be done in one shot?

Any ideas as what would be the best tool for it? One that could do the job well, and quickly? Preferably a self-centering one. I need to do 28,000 of them.

If you could tell me the brand, speeds, and feeds, it would be greatly appreciated.

Thanks ahead.

yoopertool
02-22-2008, 09:50 AM
do you have high pressure coolant available? The only way I see that you could drill that quickly with a nice finish is to have a drill with thru coolant. If you call some drill distributers or a local machine and tool distributer, they would probably have some good suggestions for you. Good luck!

cam1
02-22-2008, 07:54 PM
Hmm
Sounds like a 3 stage op to me: centerdrill,drill, then ream.Drilling will not produce close tolerance holes, or a "good" surface finish.This hole is less than 3D deep, so it could end up reasonable concentric to the axis of rotation.You may be able to get away with a 135 degree split point drill, and forego the centerdrilling, although it's better to centerdrill first.

regards

cncswiss1
02-23-2008, 11:37 AM
have your local mitsubishi supplier give you a drill to test, the MZE line if you do not have thru coolant, and the MZS line if you do, obviously the thru coolant one will be faster, but the MZE is a rockin drill. if your machine is on center you will get a good finish and hold size no problem.. i have yet to find a drill that comes even close to a mitsy, and I have tested a LOT of drills. i use them mostly in Ti6-4 and 316L and they rock in those applications.

dertsap
02-23-2008, 01:10 PM
you could go with a solid carbide drill ,if it is properly on center the hole will be dead nuts
seco has or had an insert drill that has one solid insert at the tip ,this thing had multiple tips for drilling cboring and milling . i experimented with one on 4140 with .75"dp holes ,with it being a loaner tool from our supplier we ran it until it blew up to see how many holes max we could get out of one insert , we got a little over 1800 if i recall correctly , the insert was roughly 100 bucks , the speed we gained out of it paid for the insert , the holes were perfect size and with a good finish

i don't think the machine we ran it on had thru spindle coolant

tobyaxis
04-05-2008, 02:10 PM
Honestly Indexable tooling should be used for super fast machining and high production runs on swiss.

Check out Iscar (http://www.iscar.com/) and look specifically for Index Drills

fizzissist
04-05-2008, 05:45 PM
Was looking at the Chamdrill from Iscar, and it goes down to 8mm.
Have you used them, and if so, do you think they'd work with external coolant?

I used a trick lots of years ago when I actually needed a very rough finish on a drilled hole. Had a carbide drill made with a sharp tip side relief...almost looked like a dovetail mill. Fed it in at normal speed, then drug it back out to 'score' the wall. Worked great on both my single spindles and a Davenport.

Wondering if here the idea might be to drill in, then feed slowly back out. You'd have to have thru coolant to avoid the peck marks.

If it's on a turret, you might be able to cheat and at the bottom of the hole shift the turret in X ever so slightly, so the drill tip could act like a boring bar?

Another solution might be a gun drill. I used to get beautiful finishes on deep holes.

tobyaxis
04-05-2008, 07:52 PM
Was looking at the Chamdrill from Iscar, and it goes down to 8mm.
Have you used them, and if so, do you think they'd work with external coolant?

I used a trick lots of years ago when I actually needed a very rough finish on a drilled hole. Had a carbide drill made with a sharp tip side relief...almost looked like a dovetail mill. Fed it in at normal speed, then drug it back out to 'score' the wall. Worked great on both my single spindles and a Davenport.

Wondering if here the idea might be to drill in, then feed slowly back out. You'd have to have thru coolant to avoid the peck marks.

If it's on a turret, you might be able to cheat and at the bottom of the hole shift the turret in X ever so slightly, so the drill tip could act like a boring bar?

Another solution might be a gun drill. I used to get beautiful finishes on deep holes.

External Coolant is not a good idea with these drills, nor is dragging it out slow. If you look through their site you will find the recommended Feeds and Speeds for these Drills. You can also call one of their Techs for advisement.

The ideal Indexable Insert Drill will not only drill the hole but after retracting you can offset your X-Axis to Rough, or Finish a Bore. Some of these types of drills are designed to Face/Drill/Rough Bore/Finish Bore, all in one tool call to reduce cycle times.

Personally I have not done Swiss work in quite some time now, but a lot of the experience is lingering around in limbo, LOL. Got to love Swiss though, nothing can beat them except a Multi-Spindle.;)

gizmo_454
04-08-2008, 07:07 PM
I agree with the Mits. drills. I use the MWS in both 303 and 304 and they just eat them both up! Hold great size and leave a real pretty once you get the feed/speed down.

Gizmo