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Drilling 304 stainless

ANDY79

Plastic
Joined
Nov 1, 2017
I need to drill .500 dia. thru hole in 304 stainless,
Material is 1" thick,
Any: tool, feed and speed recommendation,
Thank you,
 
Excuse me if you're already aware of this, but 304 work hardens, so you want a respectable feed rate. Kissing the work gently is a bad idea with 304. When you are cutting, cut. The feed rates suggested in the Carbide Depot link should keep you out of trouble.
 
Excuse me if you're already aware of this, but 304 work hardens, so you want a respectable feed rate. Kissing the work gently is a bad idea with 304. When you are cutting, cut. The feed rates suggested in the Carbide Depot link should keep you out of trouble.

And use a cobalt composition drill bit.
 
I need to drill .500 dia. thru hole in 304 stainless,
Material is 1" thick,
Any: tool, feed and speed recommendation,
Thank you,

Just a tip - you should provide more information next time, or you'll get shit answers to a shit post.

How many holes? 1? 10? 1,000,000?

Coolant? none? flood? High pressure coolant-through available?

Machine type? Drill press? VMC?
 
How about this:
Material: 304 Stainless Cold Rolled 225-275 HB
Tool: 0.500in 2FL HSCobalt TiN Jobber twist Drill
Speed: 30.0 SFM/ 229.3RPM
Feed: 0.0039 in/tooth 0.0078 in/rev 1.78 in/min

OR

Material: 304 Stainless Cold Rolled 225-275 HB
Tool: 0.500in 2FL Carbide TiAlN Jobber twist Drill
Speed: 136.0 SFM/ 1039.5RPM
Feed: 0.0042 in/tooth 0.0085 in/rev 8.81 in/min

OR WITH COOLANT-THOUGH:

Material: 304 Stainless Cold Rolled 225-275 HB
Tool: 0.500in 2FL Carbide TiAlN Jobber twist Drill
Speed: 204.0 SFM/ 1559.2RPM
Feed: 0.0042 in/tooth 0.0085 in/rev 13.22 in/min
 
304 SS varies considerably from cold rolled work harden to annealed condition
.
approximately the tensile strength is 2x higher and 2x harder to machine cold rolled or cold finished 304SS
.
so feeds and speeds got a spread in numbers. there is no exact answer best for all 304 SS
 
We have been recently using an inserted drill from K-Tool, called a Drill Sergeant. Looks sort of like a spade drill. It is for a .562 hole, 2" deep. We have been running 200 SFM, .004 IPR. So far we are up to nearly 400 holes on one insert, which is about $35. If you have a lot of holes, I highly recommend this. If only a few, go with cobalt-HSS.
 
304 SS varies considerably from cold rolled work harden to annealed condition
.
approximately the tensile strength is 2x higher and 2x harder to machine cold rolled or cold finished 304SS
.
so feeds and speeds got a spread in numbers. there is no exact answer best for all 304 SS

* So I will respond like this: "speeds and feeds too broad to recommend anything useful... But I have to write sumethin'"

8)
 
* So I will respond like this: "speeds and feeds too broad to recommend anything useful... But I have to write sumethin'"

8)

.
1) if part is low cost and you can loose or scrap parts you might try fastest recommendation
.
2) if part is expensive or time consuming to remake you might try the lower recommended settings especially if failure is not a option and or boss might fire you if you scrap the part
.
pretty large range there. also boss might want speed as long as you dont break $200. drill bits or boss might want you to keep tooling cost to a minimum and use cheap basic hss drill bits even if it takes 10x longer .
.
i have had boss not want to spend even $5 on tooling and couldnt care less if it took a week to drill a hole. that leaves a large range on feeds and speeds depending on job priorities and available tooling. also need to know machines available. planning job varies depending on what is available.
 
big difference in a guy with a low hp drill press and only hss jobber twist drills and another with a 20 hp cnc and carbide drills, a rigid part, good vise and through spindle coolant
.
not for nothing but i have bosses that fire a person if part scrapped and be pissed if you broke a $5 drill bit. makes a difference in how things are done
 
big difference in a guy with a low hp drill press and only hss jobber twist drills and another with a 20 hp cnc and carbide drills, a rigid part, good vise and through spindle coolant
.
not for nothing but i have bosses that fire a person if part scrapped and be pissed if you broke a $5 drill bit. makes a difference in how things are done

MAN!

You are super negative!
And/Or you are super unlucky(to put it mildly) to work with people like that.

I live in a perfect world compared to what you are talking about.

Luckily it does not seem like many people live in your kind of world.

Cheers!
 
MAN!

You are super negative!
And/Or you are super unlucky(to put it mildly) to work with people like that.

I live in a perfect world compared to what you are talking about.

Luckily it does not seem like many people live in your kind of world.

Cheers!

not negative at all just the facts in many places things are done different cause they got different priorities
.
i take part from 500 foot long 4 story tall $25,000,000. machine and boss wants some holes in a part while 100 other workers are waiting as big machine is shutdown. if i scrap part and no spares and 100 people cannot run the machine boss wouldnt be happy.
.
some of us actually work on stuff where failure is not a option and decisions have to be made based on priorities, we cant all be able to scrap $2 parts and nobody cares about it
.
or work in a place where if i break a couple of $200 carbide drills boss wont say anything about it
 
I thought the settings in post #7 were very safe Tom. Taking published data for 304 (usually assumed 160BHN) being 75 SFPM. Or using MR (machinability rating) of 40 to 45% vs B1112 (180 SFPM = 1.0 MR) and doing the BHN ratio (((160/250)*.425)*180) = 48.96 SFPM… You gotta start somewhere?

I know 304, 316 & stuff like D2 can have a personality & sometimes frustrate folks, the only thing I’d add to zero’s post would be “DON’T DWELL the tool”...

I don't think the OP is looking anyway.

Good luck,
Matt
 








 
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