Looking for a Drill Bit to Drill Stainless Steel

Well, Guv, I think that you would punch those holes out rather than drill 'em in 16ga sheet. You need a punching machine, but there ain't a thing in my skip that would do it. I'll keep my eyes peeled, though. <wheeze>.

Good answer.I think you have covered most of my suggestions. A lot of the mounting and fabricating on fire equipment has been stainless steel. I have been able to drill with HSS bits, but cobalt works much better especially with lowered speeds. I recently bought a cheap set from Grainger with their Westward brand on them. They are Titanium Nitride and Titanium-Oxide coated. These seem to resist the stainless from sticking to the bits. I have had people here destroy two drill bits just trying to drill one 1/4" hole. Low speed and lube should get better results.

Drilling Stainless, I recommend a Hi-Roc Terminator from Drill Bit Warehouse.

They manufacture the best micro-grain carbide. http://www.DrillBitWarehouse.com

800-350-8665

Try a carbide tipped drill bit. You do not say whether you are drilling by hand or is machine done ?

Hello, drilling is being done on a bench top drill press.

As every one has said slow the RPMs of the bit down. Apply pressure to bit to cut a continuous ribbon. The ribbon cutting will help in conducting some of the heat away.

One other suggestion if these holes are being drilled close to the edge Whitney makes a hand punch that would punch them. They have about a three inch reach in from the edge.

Due to the reduced relief angle of cutting edge carbide tipped drills will perform poorly.

Use slow speed and high pressure. You will find that speed and pressure are more important than the drill bits.

The maximum recommended drill speed for 1/4 inch hole in:

• cold drawn or annealed SS with hardness of 135–185 Bhn is 640 - 800 rpm
• Ferritic SS with hardness of 225–275 Bhn is 480-640 rpm

The maximum recommended drill speed for 3/8 inch hole in:

• cold drawn or annealed SS with hardness of 135–185 Bhn is 425 - 433 rpm
• Ferritic SS with hardness of 225–275 Bhn is 320-425 rpm

Drill speed may have to be as low as 150rpm for hardened SS.

As the others have said slow with steady firm pressure, using plenty of coolant. The bit must be inspected regularly, and kept sharp. If you let the bit heat up even once it will damage the cutting edge.

I bought a set of Bad Dogs that would do what you want.

Drilling 3/8" holes in 16ga. stainless can be hazardous. Clamp the piece to the work table to prevent catching on break-through and causing injury. This can occur with 1/4" holes also. Keep the carbide bits sharp. Look up speeds/feeds in Machinery Handbook or similar resource. Keep the coolant flowing!

dragon slayer79:

As "TVP45" indicated don't hesitate, the normal drilling rules do not apply when drilling SS, starting the bit then lifting to break a chip can remove some or all of the cutting edge too. Start smooth and deliberately, 150 rpm is unconscionably slow with as small of bit you're using, I'd put it at 250-350.

Can use compressed air instead of oil or coolant; makes easier to see what is going on. Custom grind bit tip to about 35° is not real pointy but will cut well under firm pressure and last longer.

If drilling hardened SS expect drill life between sharpening of about 30 seconds with hi-speed steel bits. Yeah I know what you're thinking but they are small and cheap (11%-18% tungsten) and hispeed steel bits are most cost effective, have a hoarde on hand.

I used Greenly punches to cut 7/8ths and 3/4 inch holes in stainless many times and they where great tools. You are looking at 1/4 to 3/8 and i would agree with all the other guys that sent there help . If you are using a bench press drill , set it too low speed , use a good bit ( cobalt is best ) drench with good cutting oil while you are drilling and dont overload the bit . Drop the bit to cut and then ease off and repeat .

Its like a woman , be gentle , if she starts smoking before your finished , you f/up!

An alternative.

Buy a Laser.

That would be nice but not cost effective if you aren't able to keep that laser working steadily.

Another alternative is a ceramic bit. Not a bit made for cutting ceramics but a bit made of ceramic, tempered of course. We used them in the shop to sample new alloys. A cylindrical piece of unfired ceramic (unglazed) was clamped into a drill press set at 400 rpm and a suitable coolant applied. (We used synthetic 0W-10 oil.) The shaving were collected then analyzed. I drilled many a hole through stainless that way.

Just my two cents Dragon

Hello,

We are regularly drilling holes in Stainless steel

We use normal HSs drill bits with four facet grinding

but the trick is to have higher than 0.1 mm feed per revelution

and we use Tri Chloro Ethelene (TCE) as coolant.This is

a magic coolant.

Regards

Kishore K.Gupta

pyn@airtelmail.in

New Delhi India

I noticed that a guest from India stated to use "Tri Chloro Ethelene (TCE) as coolant". Please note that that has been banned in US in most applications. It is known to cause cancer. It use to be used as a dry cleaning agent for clothes. Your hardware store should carry a "thread cutting oil". It will work fine, however as stated many times above, the main thing even for ordinary steel is to slow the speed to 400 RMP to 150 RPM. Most people think the harder the material the faster you should drill. It's actually the opposite.

Dagaon Slayer79:

Serveral things:

• You want a drill bit that is designed for stainless with a special relief and split point.
• Second you need a high-moly tungston or mollidium steel, not cobalt, carbide or regular high speed bits. The first two are two hard and the latter is too soft.
• Concerning speed, in never recomend rpm's (two difficult to count) just drill decrease the speed and increase the feed until you get nice long currely chips.
• A good cutting oil like Ultra Lube also helps.

Our Winzer Shop Pro Drills Bits and Shop Pro Taps work very well on 300 (304-308 and even difficult 316) and 400 series stainlesss. I have power plants, steel mills and other heave industries (auto, food and beverage, pharmacutical) that say nothing else works better.

Cobalt alloy bits are good for stainless steel but as many have pointed out the speed of the drill and the pressure used are more important.

With 16ga stock the backing plate is going to be critical or you are going to deform the sheet. I suspect that you have kept your pressure low to avoid deformation and are therefore allowing the piece to work harden. With this thickness of stock you have a problem. You need the pressure but the pressure ruins the work. Catch 22.

One poster mentioned using trichloroethylene as a coolant. That will work but be aware that trichloroethylene is a suspected carcinogen and any chlorinated hydrocarbon is hazardeous waste that will be a big disposal issue. There are health hazards with breathing the vapors and touching the material as well.

With all that I would agree that a punch would be a better way to go.

Try using turpentine as a coolant, I have had pretty good luck with cobalt bits and turpentine and slow turning speed. I usually drill in 1/8"-1/2" though but sometime sdrill the thinner sheets.

pipewelder

sulfur based cutting fluids for nickel based SS steels (300 series) work best because the sulfur will combine with the nickel and form a low melting point eutectic that allows the cutting tool to dig into the material faster. The only warning I would make is to clean the workpiece VERY VERY well after the drilling is done to get the sulfur off the workpiece before doing any subsequent work on the piece (especially welding or heat treating).

This PDF file from North American Steel/Sheffield Steel on machining their 316L G&P shafting has very good data for you to use.

http://www.northamerican-steel.com/pdf/38-40.pdf

Most of the forums replies are correct in the ways of drilling stainless ,but neglect you are drilling relatively thin sheet S/S.

First problem is heat build up is rapid due to thin cross section which leads to poor cutting action hardening, drill damage and galling. Cooling fluid helps to reduce this but in thin section it is not so effective.

Second as a drill breaks through a thin section it looses its stability and wanders which not only leads to more drill damage but leaves an out of round hole.

If you are drilling large numbers of these holes an investment in step drills [ not the cone shaped ones ] would better serve you, these help by drilling a small pilot hole which guides the second cutting face through and drilling against a hardwood backing would help even more.

Use a drill guide mounted in a fixture, suggest drill several sheet together and clamp hard with or immediate to drill guide to prevent sheet deformation.

Use tool steel a.k.a. hi-speed steel having 15%-22% tungsten/molybdenum, use a multi-angle grind and if can find cutting oil used for old fashioned heavy steel reciprocating saws for high sulfur content is excellent. May be sourced from Schaefer industrial lubricants.

Recommended drilling speed charts take for granted depth of drilled hole will at least equal diameter of drill. That said start slow about 150 rpm and experiment; each set up is different, slow down, think about what you are doing and be careful drills can and often do shatter so wear safety shield in addition to safety glasses.

turn-two

Hello Dragon,

Although you may have enough information to explore what may work best for you based on all the good responces, one last thing to think about. I had a similar problem drilling cast stainless steel and had to ensure we were getting the best results. I brought in a few tool distributors who do this everyday and asked them for advise. They have tooling budgets that they can bring in the tools, do trials and prove the process without any risk to your pocket book. Confirmation of the work holding, speeds and feeds, coolant versus dry machining all were worked out without any additional charge except for the final tool that did the job.

Good Luck!

AquaLung

Suggesting 2 alternatives:

• If you need only a few holes/hour: Go for a handpress and Carbide Punchsets 1/4",3/8"
• If you need vast no of holes, get a CNC laser drill to burn out the circular peripheries of holes dia 6.5 or 10 mm - beginning from a cetering entry hole-also drilled in the CNCprogram
• If your need is irregular but you want a reliable last resort - first pierce a small pilot hole dia 1>2mm with a hand punch/die. Then using a plasma Arc to cut small or big holes manually.Plasma Arc machines are cheap and available to 16 mm thick SS plates. Want some ? Can sell to you.
• Forget Drilling.

Most, if not all of this has already been said but...

1. Alwayse use coolant. Motor oil works in a pinch. If it stops smoking, stop drilling and put more!

2. Take a heavy cut to keep the tool in the "cool" part of the material. Often people refer to work hardening in stainless but it is a minor problem as compared to overheating!

3. Check out your RPM rates here: http://www.multi-drill.com/drill-speed-chart.htm

Make sure you are spinning at that speed or slower. Slower simply means it takes longer and these numbers are based on HSS tooling.

AutoDrill
50 Division Avenue
Millington, NJ 07946
Ph: 800-871-5022
Fax: 908-542-0242
www.AutoDrill.com
www.Multi-Drill.com
Sales@AutoDrill.com

I know of a company that has just created a new drill bit design. It drills through stainless steel like cutting through butter. Its life is 3 times longer than regular HSS cobalt drill bits and it drills 50% faster. Their company is working on the patent and trade mark first before they release the name of it. If anyone has any questions you can email me at fluteyinc@live.com

Hey, I'm sure interested in getting my hands on those bits!

A high molly-tugston (spring steel) works better and you want to drill slow and increase feed for best results.

If you are able to drill a pilot hole you could use a step bit

Call Drill Bit Warehouse. Or go to the site http://www.drillbitwarehouse.com they manufacture a sub-micro grain carbide straight flute that is amazing.

use high peformance drills tin coated or tialin coated, these should do the trick, one brand is Nachi very good brand and these would last you forever with regular sharpening after couple of hundred of holes. hope this helps

If you have some Stelite welding rod available try this. Take a short piece of proper dia and grind a nail point on the end. This will not grab but definitely will build heat but of short duration in that thickness. Very cheap leftovers from a welding shop.

I have drilled holes in files with this method.

That much heat would probably sensitize SS.

A mine of info on here for sure. I was interested to see turps mentioned as a luricant for drilling s/s. I spent some time in a commercial workshop and we always used kerosene as the lubricant when drilling s/s. Out of fashion now or proven inferior?

what is the size of the job?.

If the size of the job is small make a drill jig fixture with hardened drill bushes .

use a M42 HSS center drill (ground to your required size).

HIGHLY FLAMMABLE STUFF. USE PRECAUTION AND have a FIRE EXTINGUISHER NEAR YOU WHEN YOU USE THIS COOLANT. use a thin stream of Isopropyl alcohol or ethyl alcohol & oil mixture as coolant . isopropyl alcohol will provide cooling to the drill and job as it evaporates and oil will provide lubrication.Please have a good ventilation and and exhaust to drive out the alcohol vapors from the room ( better to do it in the open area (outside). please ensure no fire or any sparking electric source is present in the vicinity when this coolant is used. HIGHLY FLAMMABLE STUFF.

drill jig fixture and bushes will eliminate drill wander. keep the rpm of drill down and press with reasonable force ( feed) as other members have suggested. CLAMP DRILL JIG FIXTURE TO DRILL PRESS AND JOB TO DRILL JIG FIXTURE TO ELIMINATE ACCIDENTS AND INJURY.

with thin sheet , twist drills tend to get stuck in the flutes when the hole is getting opened, that is the reason a center drill is to be used as it does not have twist flute and it also provides a pilot hole and then the hole that you require ( body of the center drill has to be ground to your required size).

I used to employ this technique to drill 10 mm holes in 1.0 mm thick SS 316 sheets.

If the job quantity is large is large, try clamping several sheets stacked up in an appropriately designed drill jig fixture and then drill . it will result like drilling a thick sheet ie (1.6mm x 10 sheets=16 mm). In this procedure you could use a jobber twist drill .

I apologize for writing a long post,but I hope my suggestions are useful to you.

Happy drilling

Hyder Imani

Solid carbide drill bits with sharpened split point tips.

RHC - Rockwell Hardness C

HSS Drill Bits - Work well up to the 50ish RHC

Drill - Mild steel, Some tool steel, Some Spring Steel

No Drill - Hard Plate, Anti Drill Plate, 404c Stainless Steel

Pro - Good in Hand Drills and most drilling applications

Con - Has limitations in hardened steels

Cobalt - Works up to 58ish RHC

Drill - Mild Steel, Some Spring Steel, Some Tool Steel

No Drill - Hard Plate, Anti Drill Plate, 440C Stainless Steel

Pro - Good for hand drills and most drilling applications

Con - Has limits with hardened steel

Carbide Tipped - Will drill almost any steel, Hard, Stainless or Mild.

Pro - Drills all steel

Con- Blunt tip requires extreme pressure to produce cuttings. Drill bit is hard to start on all steels.

Diamond Coated Drill Bit - Cuts on most steels(Not Hard Plate) just not for long.

Pro - Will Drill most steels (Not Hard Plate)

Con - Cutting stops quickly after diamond grit has warn off, Then behaves like HSS bit

Solid Carbide Drill Bit - Cuts all steels.

Pro - Sharpened points wont "walk" like carbide tipped bit. Cuts all steel

Con - Sharp tip and fine edges can chip easily and ruin drill bit. Not for hand drills. Expensive!

For more information enter "The Ultimate Guide To Drill Bits" ____ Tube video into your favorite search engine and watch the video.