Best method for cutting stainless steel?

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Schnitzengiggle

Schnitzengiggle

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I have a very small project that I am working on and I need to cut a piece of stainless tube (just 2 simple straight cuts). It is my understanding that when using a hacksaw, or any type of non stainless metal-to-stainless metal cutting, the stainless becomes contaminated with the other steel and can rust at that point.

So my question is do I cut with a hacksaw or sawzall, then clean up with sandpaper, or will a cutting disk on my miter saw be better?

FWIW, I don't have a miter saw cutting disk, so I will have to incur that cost if I want to do it that way (which would provide the cleanest most accurate cut I assume), but I have a hacksaw.

What would you do/suggest?
 
As a machinist I would have to call BS on the "contamination" of the stainless steel. There's a chance if an inferior quality cutting tool was used that there may be some build-up on the cut surface that may oxidize, but that doesn't mean the stainless has changed. Stainless steel has high levels of nickel and chrome that make it less prone to oxidation. Having a little high speed steel rusting on its surface isn't going to change that. If you were worried you could hit it with a little sand paper, but you should probably do that anyway.
 
How big diameter is the tubing? If its thin wall tubing you can just use a tubing cutter on it like the ones used for copper pipe. Just take your time and dont try to cut to much at one time.
 
I recommend just using the hacksaw. When you're done, take some 220 grit sandpaper, fold it up so it fits the slot snugly, and sand it. This will remove any material that the hacksaw may have deposited on the SS. That's the stuff that will rust later, not your stainless, so you want to get it off.

I used the same technique (I also used Scotch Brite on some stuff, but that wouldn't be appropriate for your application) for every cut that I made for my electric keggle and nothing has rusted yet, and it would have by now.
 
bottlebomber said:
As a machinist I would have to call BS on the "contamination" of the stainless steel. There's a chance if an inferior quality cutting tool was used that there may be some build-up on the cut surface that may oxidize, but that doesn't mean the stainless has changed. Stainless steel has high levels of nickel and chrome that make it less prone to oxidation. Having a little high speed steel rusting on its surface isn't going to change that. If you were worried you could hit it with a little sand paper, but you should probably do that anyway.
Click to expand...

Yeah I understand that a little sandpaper, and a scrub with some BKF will more than likely remove any metal contaminant that may cause rust. Since this will be immersed in the beer, I want to make sure there aren't any corrosion issues from any contaminants.

I was wondering if a cutting disk would avoid any metal contamination, but then you run into the problem of overheating which is another can of worms.
 
What exactly are you making to be concerned about overheating?
 
I am making Randall.

I overheard Palmer on a Brew Strong podcast talking about stainless steel and cutting it and the potential hazards of contamination and overheating of the stainless when using certain methods to cut it.

Maybe I'll just take the spear to HD, open up a pipe cutter, cut it there and leave, lol.
 
I've used both saws-all bi-metal blades and angle-grinder cut-off wheels on my kegs without issue. Using a hacksaw by hand would likely take forever to cut through SS.
 
Ravenshead said:
Using a hacksaw by hand would likely take forever to cut through SS.
Click to expand...

Agreed, I think the pipe cutter is probably the cleanest and most accurate method. That is my plan.

EDIT: The pipe cutter I own fits! Sweet! took a while to cut the valve off the spear, but it is accurate, and a nice clean cut.
 
Schnitzengiggle said:
Agreed, I think the pipe cutter is probably the cleanest and most accurate method. That is my plan.

EDIT: The pipe cutter I own fits! Sweet! took a while to cut the valve off the spear, but it is accurate, and a nice clean cut.
Click to expand...

You still need to sand the cut edge to remove any material that might have transferred from the cutter if you're concerned about contamination.
 
Ravenshead said:
Using a hacksaw by hand would likely take forever to cut through SS.
Click to expand...

It's really not that bad. I cut through a 1/2 inch coupling with a hacksaw - 3/4 ID, 1 inch OD, 1/8 thick wall. It took a while, but that's mainly because I didn't want to heat the SS, so I sawed slowly and when the metal began to get a little hot I stopped to let it cool. If you let it get too hot then it probably would get real hard to saw.
 
DeafSmith said:
It's really not that bad. I cut through a 1/2 inch coupling with a hacksaw - 3/4 ID, 1 inch OD, 1/8 thick wall. It took a while, but that's mainly because I didn't want to heat the SS, so I sawed slowly and when the metal began to get a little hot I stopped to let it cool. If you let it get too hot then it probably would get real hard to saw.
Click to expand...

A few drops of oil once you've got the cut started would probably get you a long way with the heat problem..
 
The pipe cutter worked great, I used the handle end of adjustable wrench to debur the edge, which also worked great.

My pipe cutter needs a new blade though, the screw that holds the blade was loose, and I didn't realize it, so the pipe slipped out and the blade chipped, but I got the pipe cut.
 
As a welder with over 20 years experience and certifications welding stainless steel,
I agree with bottlebomber.
Some people have created misunderstandings about stainless steel.
 
Schnitzengiggle said:
The pipe cutter worked great, I used the handle end of adjustable wrench to debur the edge, which also worked great.

My pipe cutter needs a new blade though, the screw that holds the blade was loose, and I didn't realize it, so the pipe slipped out and the blade chipped, but I got the pipe cut.
Click to expand...

When I was first reading this thread, I was thinking that a reciprocating saw may work well, but I'm glad to know now that I can just use the one at HD. :rockin:
 
I have had good luck in the past with something very similar to this cutting stainless. Put the correct metal bit on there. Have a couple extra--you might break a couple bits getting the hang of it.

http://www.blackanddecker.com/power-tools/JS515.aspx

The speed can be slowed down super slow--so less heat. As slow as a hack saw--without the work. Have a can Pam for cutting oil. Have ear plugs. Can be Loud. But works well. Don't go fast and over heat the bit or the steel.
 
As I've mentioned earlier I was successful at cutting the stainless pipe.

Now my dilemma is drilling the 21, 1/16" holes into the tube. I assume cobalt bits will be best for this application.

Any suggestions on this? I killed 2 standard metal bits last night (because I had them), and didn't even manage to punch a single hole through.

I have drilled stainless before, but never with bits as small as 1/16", I assume that I will need more than one to finish the job.
 
The SFPM of cobalt is about twice that of high speed steel, so it would be a good place to start. Do you know what kind of stainless it is? There's a huge difference between 303 and 316, for example. Also, you've got to be able to have your drilling setup as rigid as possible. Do you have a vice? If not, you may need to have someone help you hold the workpiece while you hold the drill as rigidly as possible. Spinning the drill slowly is not a good idea. Ideal cutting speed for even a HSS drill bit of 1/16" into stainless is about 9000 rpm. Slow speeds will drag on the bit, causing it to chip and burn up. Also, when you burn up a drill in a hole, and try to re-drill it you are trying to drill a work-hardened surface, with melted down drill material built up in it that is much harder than the SS. You also need to figure out some kind of coolant.
 
bottlebomber said:
The SFPM of cobalt is about twice that of high speed steel, so it would be a good place to start. Do you know what kind of stainless it is? There's a huge difference between 303 and 316, for example. Also, you've got to be able to have your drilling setup as rigid as possible. Do you have a vice? If not, you may need to have someone help you hold the workpiece while you hold the drill as rigidly as possible. Spinning the drill slowly is not a good idea. Ideal cutting speed for even a HSS drill bit of 1/16" into stainless is about 9000 rpm. Slow speeds will drag on the bit, causing it to chip and burn up. Also, when you burn up a drill in a hole, and try to re-drill it you are trying to drill a work-hardened surface, with melted down drill material built up in it that is much harder than the SS. You also need to figure out some kind of coolant.
Click to expand...

It is a 9-7/8" piece of Sanke dip tube (304?)

I use a small drop of cutting oil on the site. I think one of my issues was not placing the bit as far into the chuck as I could get it, just allowing enough of the bit to protrude to create the hole (more rigid then the entire bit sticking out of the chuck--too much flex with that small of a diameter).

I do normally reduce the spin of the drill, I am using a 1/2" Milwaukee Hole Shooter, its max RPM is 800, but has sufficient weight to help steady it.

Yes I have a small vice that I am using to stabilize the pipe, so n issues there.

I would be grateful for any other tips anyone can provide.
 
bottlebomber said:
... Ideal cutting speed for even a HSS drill bit of 1/16" into stainless is about 9000 rpm. Slow speeds will drag on the bit, causing it to chip and burn up. Also, when you burn up a drill in a hole, and try to re-drill it you are trying to drill a work-hardened surface, with melted down drill material built up in it that is much harder than the SS. You also need to figure out some kind of coolant.
Click to expand...

Are you sure 9000 RPM, I'm finding reference to 17 SFM for non free machining austenitic SS, and only up to ~40 from free machining SS.
This would be around 1000 RPM for 304 with a 1/16" drill.
Also I'm confused about you comment on work hardening, are you trying to say that when you let the piece et to hot you arn't actually work hardnening the SS but melting the drill into it?
 
If drill bits are not doing the job for you then use a 1/16" grinding burr on the end of a rotary tool like a Dremel. You should have no trouble making holes in stainless with that setup.
 
mattd2 said:
Are you sure 9000 RPM, I'm finding reference to 17 SFM for non free machining austenitic SS, and only up to ~40 from free machining SS.
This would be around 1000 RPM for 304 with a 1/16" drill.
Also I'm confused about you comment on work hardening, are you trying to say that when you let the piece et to hot you arn't actually work hardnening the SS but melting the drill into it?
Click to expand...

The work hardening happens very fast. The heat buildup is what happens as a result of hardening when the drill bit spins an kind of mushes the metal around instead of cutting it.This can be in one revolution of the bit. If you catch it fast enough you can change bits and drill through a little bit of it but if it gets really hot its pretty much too late for that hole. I have just melted through thin stuff before and that might work with this. Done properly with lots of pressure, lean on it pretty good, this is pretty hard with small bits and a hand drill, you should get it done. . A drill press would make this much easier.
 
Use one of these

200px-CenterDrills123456.jpg


http://www.mcmaster.com/#starting-drill-bits/=fbfgym

I know they have a countersink but just use the drill point of the bit.

These things go through stainless with ease.
 
mattd2 said:
Are you sure 9000 RPM, I'm finding reference to 17 SFM for non free machining austenitic SS, and only up to ~40 from free machining SS.
This would be around 1000 RPM for 304 with a 1/16" drill.
Also I'm confused about you comment on work hardening, are you trying to say that when you let the piece et to hot you arn't actually work hardnening the SS but melting the drill into it?
Click to expand...
Im not sure where that number came from, but 17 is snail-crawling. I would use a speed like that for cutting Hastelloy or Inconel. 304 is pretty tough, but not that tough. I was figuring for free machining stainless, but even for 304 you should be at least 50 SFM - that's 3000 RPM using SFM/.262/cutter diameter.
Work hardeining is different from cutting tool build up. I've had things get so hard from a carbide turning insert getting too dull that they turned straw colored and at that point they are unmachinable.
baldric said:
If drill bits are not doing the job for you then use a 1/16" grinding burr on the end of a rotary tool like a Dremel. You should have no trouble making holes in stainless with that setup.
Click to expand...
That's why I was asking about wall thickness. A diamond burr would be the tool for the job if it was just some tubing or something. Im not familiar with whats being worked on because I don't keg.
 
dmfa200 said:
Use one of these

http://www.mcmaster.com/#starting-drill-bits/=fbfgym

I know they have a countersink but just use the drill point of the bit.

These things go through stainless with ease.
Click to expand...

Those center drills do work great, the #1 is a 1/8" shank I'm pretty sure. It would be much more rigid than a drill, but as soon as one of those makes it through its going to wallow out the hole with that chamfering edge. It could work though.
 
bottlebomber said:
Those center drills do work great, the #1 is a 1/8" shank I'm pretty sure. It would be much more rigid than a drill, but as soon as one of those makes it through its going to wallow out the hole with that chamfering edge. It could work though.
Click to expand...

I never think of using my center drills for thin stuff but its a great idea.
I think thats the best bet.
 
bottlebomber said:
That's why I was asking about wall thickness. A diamond burr would be the tool for the job if it was just some tubing or something. Im not familiar with whats being worked on because I don't keg.
Click to expand...

It is tubing, but I don't know the thickness.

About 1/16", 0.065?
 
Schnitzengiggle said:
It is tubing, but I don't know the thickness.

About 1/16", 0.065?
Click to expand...

You may be able to find a diamond grinding bt that would do the job nicely. It will be hard to have them only be 1/16" though, they will probably be more like 3/32 as many of these bits are cone shaped. Oh and I forgot to ask, are you using anything to spot/center punch your holes? Pretty much vital for drilling into a rounded surface. Also I can't remember if this has been asked before, but what is the function of the holes?
 
Brew_Force said:
A dremel with the metal cutting blade.
Click to expand...

That's what I was thinking, a cut off wheel. I was wondering why they need to be holes instead of slots.
 
bottlebomber said:
Those center drills do work great, the #1 is a 1/8" shank I'm pretty sure. It would be much more rigid than a drill, but as soon as one of those makes it through its going to wallow out the hole with that chamfering edge. It could work though.
Click to expand...

Don't go plunging down with your drill and you won't have that happen. Center drills cut through material easier than a drill bit, so you don't have to use excessive force. You'll feel the moment the center drill is about to cut through the tubing.
Then you just back off the pressure allowing just the drill point to make the hole.
If you have a drill press than it's even easier.
 
plasma cutter will give a nice cut for plate or thick stainless...and oxidation may occur but wire weel it or get sand paper and hit it for a bit. for a sanke spear a pipe cutter or hack saw with metal cutting blade should work well
 
bottlebomber said:
Those center drills do work great, the #1 is a 1/8" shank I'm pretty sure. It would be much more rigid than a drill, but as soon as one of those makes it through its going to wallow out the hole with that chamfering edge. It could work though.
Click to expand...



I want 1/16" holes
 

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