Drilling stainless steel

[clogs]

John Hall
wouldn't know where to buy em here.....hahaha......

 

[Seascaper]

I should have asked earlier, are you using a drill press or trying to do this with a hand held drilling machine ?
If the latter, I doubt you will have much luck.
Drilling stainless requires relatively slow constant speed with quite a degree of constant force.
If you do it right, you will get a lovely spiral swarf from the flutes of the drill.
I have NEVER used any lubricant / coolant ( except when tapping threads ) - if you need that your drill is going too fast.
With such a thin material, I doubt you will need to retract the drill to clear the swarf.
I have never needed cobalt drills, just standard drills - sharp
Most of my work is with stainless, and just the other day I drilled an 18 mm hole - 35 mm deep with a standard drill and had no problems. I usually go up in steps of 4 mm

Hello,
I am using a drill press, a Meddings, when I get back to my workshop next week I will give it another go at a much slower speed. I was using 3 in 1 as a lubricant. The drills were normal HSS newly sharpened. The metal is 316 stainless box section 100 x 50mm x 3 mm thick. I have now watched a few YouTube videos, one guy mentions the weld where you can get a hard area but I am pretty sure I had avoided this area. I do need to drill some 16mm holes for some large bolts when I get back. On one video using a hole saw was shown so I might get one 16mm size that fits my arbour. But then it looks easy on the video.
Regards

 

[Seascaper]

Hello,
I am using a drill press, a Meddings, when I get back to my workshop next week I will give it another go at a much slower speed. I was using 3 in 1 as a lubricant. The drills were normal HSS newly sharpened. The metal is 316 stainless box section 100 x 50mm x 3 mm thick. I have now watched a few YouTube videos, one guy mentions the weld where you can get a hard area but I am pretty sure I had avoided this area. I do need to drill some 16mm holes for some large bolts when I get back. On one video using a hole saw was shown so I might get one 16mm size that fits my arbour. But then it looks easy on the video.
Regards

I had to remove the hardened metal and tidy up the hole with a dremmel and small grinder attachment. As you can imagine an easy job was in this case a nightmare of a job.

 

[Stevekane]

apologies as this is not helping you directly but just as a matter of intrest I had to drill 25mm holes through a mild steel plate about 12mm thick, and used a mates Mag Drill with a broach, I had never used one before but it was just so effective, and I was left feeling it was just such a clever bit of kit,,btw it wouldnt stick to decent stainless either so a doubly useless bit of info,,,
Steve.

 

[sawtooth-9]

Hello,
I am using a drill press, a Meddings, when I get back to my workshop next week I will give it another go at a much slower speed. I was using 3 in 1 as a lubricant. The drills were normal HSS newly sharpened. The metal is 316 stainless box section 100 x 50mm x 3 mm thick. I have now watched a few YouTube videos, one guy mentions the weld where you can get a hard area but I am pretty sure I had avoided this area. I do need to drill some 16mm holes for some large bolts when I get back. On one video using a hole saw was shown so I might get one 16mm size that fits my arbour. But then it looks easy on the video.
Regards

3 in 1 may be part of your problem.
My experience is that you do not want lubrication. The drill bit has to" bite " into the stainless to get a good cutting action. If you need coolant, your drill speed is too fast.

 

[D_W]

3 in 1 may be part of your problem.
My experience is that you do not want lubrication. The drill bit has to" bite " into the stainless to get a good cutting action. If you need coolant, your drill speed is too fast.

mirroring mine - but being uneducated and just looking to drill clean. Water doesn't impede the cut, but its steaming off tells right away if things aren't being kept cool.

The science of cutting with machines and what's productive in ...production ...is probably well proved with data. if the steel isn't hardened when the job is started, though, it can be cut. It's most likely chromium or chromium and nickel and they are slick and can impede cutting, but they don't stop it.

Filing is the same - stainless dulls my files faster and makes them seem difficult before they're "really dull", but it can be filed. A couple of seconds of heat though and the "oops, it just cooled" and life is very difficult, whether it's through and through, or just surface. Either way.

 

[sawtooth-9]

Wh

I was tought go in slow n hard.....no coolant.....on S/Steel

Cobalt drills are really not that expensive anymore...perhaps 50% ......
I dont buy HSS anymore......
I have to drill hundreds of holes in angle iron and other carp steels, often up a ladder and overhead......
Sorry for the PUN but unless u have super branded HSS ^they just dont cut it).....
I've bought thousands of HSS drill bits over the years and even quality bits can often do with a lick on the grinder before use....
PS, as my holesaws wear out they are also replaced with cobal now....
come to think of it, my smaller HSS metal lathe tools have cobalt in em....most of the standard stuff I've given away.....

Sawtooth, have u tried the metal lathe cutting steel from Eccentric Eng, also of ur Parish, OZZ....
I'm quite impressed with it on my smaller lathe.....

at is this ?

 

[sawtooth-9]

There seems to be a lot of issues with people machining stainless.
Most of my metal work is with stainless, brass and cast iron - and each have their own characteristics.
Whether I mill, turn or drill stainless, I have very few problems.
The secret is to keep it cool - not with coolant, but with gentle cuts, firm pressure and sharp tools.
If you look at my post " Twisted " you will see quite a bit of stainless cutting, turning, milling and drilling work - NONE done with ANY lubricant or coolant.
It may take a little longer, but the result ends up so much easier than working mild steel !

 

[Seascaper]

Hello,
To let you know that I now got the drills to cut into the stainless normally as one would expect. The drill speed was too high so I moved the belt to its slowest setting and all was ok.
Regards

 

[Keith 66]

I used to machine a fair bit of stainless steel for boat fittings, For drilling slower speeds & good feed pressure are the recipe for success. Plus use plenty of cutting oil it keeps the drill tip cool!
I always use a good synthetic cutting oil, Turning Stainless i use the same stuff, I use Hss tools & they cut with a great finish & last well. Never had the need for cobalt drills.

 

[John Brown]

I have never seen any other reference to this, so take it with a giant pinch of salt, but a chap I worked with half a century ago made his own three sided centre punch by grinding a hex key(and possibly hardening it). He reckoned that didn't work harden the SS like a regular punch. He'd trained as a toolmaker and generally knew his stuff, but as I say, I've never heard of it since. He also advocated the "keep it cutting" policy.

 

[clogs]

for anyone still interested in the larger holes.....
I use these quite a bit...they are not expensive at all....
I bought a few just to see how they worked...
I was up a ladder 4m high drilling 16mm holes in 3mm thick Z purlins....
after about 50 holes they still cut fine...no coolant.....this was with a corded hand drill.....
my Mag Drill machine was to big n heavy to get in....
I normally use cobalt hole saws.....but they cut to slow....also now old school....

Keith 66
over a year I must drill 1000's holes..
Diy'ers drilling lumps of angle and god knows what else would benefit from Cobalt...
the best thing about Cobalt drill is the performance for a few pence more....
plus u practically never need to sharpen em...
How many on here can make a decent job of sharpening by hand a HSS bit....???
I've been doing it for 50 years and only 99% get it right on the smaller drills...
just getting old...
just for a laugh buy just a few reg sizes and try em, less than the price of a pint...
u'll be presantly suprised....
PS, if u can sharpen a HSS drill u can sharpen a Cobalt one...

 

[Dave Moore]

for anyone still interested in the larger holes.....
I use these quite a bit...they are not expensive at all....
I bought a few just to see how they worked...
I was up a ladder 4m high drilling 16mm holes in 3mm thick Z purlins....
after about 50 holes they still cut fine...no coolant.....this was with a corded hand drill.....
my Mag Drill machine was to big n heavy to get in....
I normally use cobalt hole saws.....but they cut to slow....also now old school....

Keith 66
over a year I must drill 1000's holes..
Diy'ers drilling lumps of angle and god knows what else would benefit from Cobalt...
the best thing about Cobalt drill is the performance for a few pence more....
plus u practically never need to sharpen em...
How many on here can make a decent job of sharpening by hand a HSS bit....???
I've been doing it for 50 years and only 99% get it right on the smaller drills...
just getting old...
just for a laugh buy just a few reg sizes and try em, less than the price of a pint...
u'll be presantly suprised....
PS, if u can sharpen a HSS drill u can sharpen a Cobalt one...

View attachment 144060

These are really good on st/steel, we used them at work for cutting holes in pipe.

 

[Keith 66]

In answer to Clogs, Maybe i will try cobalt next time i have a big drilling job, But i havent had the need to buy drills for years since the day i cleared a couple of engineering workshops in a college & school, I ended up with enough boxes of drills to last me a lifetime!
You are right about not many people know how to sharpen drills & HSS lathe tools, I was taught how to do it properly many years ago & Its a useful skill.