Drilling Stainless Steel

[Warren Kaplan]

I had to put some holes in a stainless steel halyard organizing plate that will go beneath my mast step. I'm learning some "hard" lessons along the way. Project ain't quite finished yet either. I read up on drilling stainless before I started but I didn't do everything they suggested. I should have and I will when I "press on" with the project.
First, stainless, depending on its grade, is very hard. You need to use cobalt or titanium bits or maybe carbide will do. Because stainless is so hard, when starting the hole, the bit tends to "walk" away from the mark. This creates all kinds of problems when you have to drill holes spaced exactly (like exactly below the holes in the mast step). That's where I screwed up and when I placed the mast step over one hole in the plate, all I saw was half a hole below another mast step hole. Lucky for me I can just shift the plate a little and start over again. Use a center punch to mark your spot. Drill a pilot hole of smaller size first! Use LOW SPEED for drilling stainless. Heat generation is anathema to stainless. It can crystalize it, so I've read, and make drilling harder. It also ruins the drill bit. So go slow! Use cutting oil! I don't know exactly what makes an oil "cutting oil" but I will find out. The oil not only lubricates, but like in an engine, it cools the work which is important. I tried to do this with my hand held drill. Because of the bit walking, it makes accurate drilling very difficult. It also requires alot of pressure. The organizing plate isn't on the boat yet so I can take it to my shop (read basement). I think the most important thing in all this is to do this on a DRILL PRESS. I'll clamp the work down. Accurately mark where the holes should be and I won't have any trouble with the bit slipping an 1/8" making the hole useless. I think that's the biggest problem....getting the drill to drill the hole(s) EXACTLY where I want it! Any further suggestions are anxiously awaited!!

Warren Kaplan
Sine Qua Non
CD27
Oyster Bay Harbor, NY



Setsail728@aol.com

[Dana]

I just installed two new 2"x2"x!/4" SS angle iron motor well brackets with six holes each which had to match the hole locations on my CD26. Not all drill bits are created equal. Center punching and the use of DeWalt Cobalt drill bits, 135 degree angle was the answer......I did not use a drill press but of course...pressure...

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I had to put some holes in a stainless steel halyard organizing plate that will go beneath my mast step. I'm learning some "hard" lessons along the way. Project ain't quite finished yet either. I read up on drilling stainless before I started but I didn't do everything they suggested. I should have and I will when I "press on" with the project.
First, stainless, depending on its grade, is very hard. You need to use cobalt or titanium bits or maybe carbide will do. Because stainless is so hard, when starting the hole, the bit tends to "walk" away from the mark. This creates all kinds of problems when you have to drill holes spaced exactly (like exactly below the holes in the mast step). That's where I screwed up and when I placed the mast step over one hole in the plate, all I saw was half a hole below another mast step hole. Lucky for me I can just shift the plate a little and start over again. Use a center punch to mark your spot. Drill a pilot hole of smaller size first! Use LOW SPEED for drilling stainless. Heat generation is anathema to stainless. It can crystalize it, so I've read, and make drilling harder. It also ruins the drill bit. So go slow! Use cutting oil! I don't know exactly what makes an oil "cutting oil" but I will find out. The oil not only lubricates, but like in an engine, it cools the work which is important. I tried to do this with my hand held drill. Because of the bit walking, it makes accurate drilling very difficult. It also requires alot of pressure. The organizing plate isn't on the boat yet so I can take it to my shop (read basement). I think the most important thing in all this is to do this on a DRILL PRESS. I'll clamp the work down. Accurately mark where the holes should be and I won't have any trouble with the bit slipping an 1/8" making the hole useless. I think that's the biggest problem....getting the drill to drill the hole(s) EXACTLY where I want it! Any further suggestions are anxiously awaited!!

Warren Kaplan
Sine Qua Non
CD27
Oyster Bay Harbor, NY

darenius@aol.com

[len]

warren

right on! - i find titanium bits useless, carbide work if i go very very slowly - i found a product called "magic tap oil" that helps too -

len

[John R.]

Cobalt bits, grind the tips to an aggresive angle (sharp pitch), Marvel Mystery oil. Step the bit size (don't start too small or it will break when it exits), use a drill press whenever possible.

I had to put some holes in a stainless steel halyard organizing plate that will go beneath my mast step. I'm learning some "hard" lessons along the way. Project ain't quite finished yet either. I read up on drilling stainless before I started but I didn't do everything they suggested. I should have and I will when I "press on" with the project.
First, stainless, depending on its grade, is very hard. You need to use cobalt or titanium bits or maybe carbide will do. Because stainless is so hard, when starting the hole, the bit tends to "walk" away from the mark. This creates all kinds of problems when you have to drill holes spaced exactly (like exactly below the holes in the mast step). That's where I screwed up and when I placed the mast step over one hole in the plate, all I saw was half a hole below another mast step hole. Lucky for me I can just shift the plate a little and start over again. Use a center punch to mark your spot. Drill a pilot hole of smaller size first! Use LOW SPEED for drilling stainless. Heat generation is anathema to stainless. It can crystalize it, so I've read, and make drilling harder. It also ruins the drill bit. So go slow! Use cutting oil! I don't know exactly what makes an oil "cutting oil" but I will find out. The oil not only lubricates, but like in an engine, it cools the work which is important. I tried to do this with my hand held drill. Because of the bit walking, it makes accurate drilling very difficult. It also requires alot of pressure. The organizing plate isn't on the boat yet so I can take it to my shop (read basement). I think the most important thing in all this is to do this on a DRILL PRESS. I'll clamp the work down. Accurately mark where the holes should be and I won't have any trouble with the bit slipping an 1/8" making the hole useless. I think that's the biggest problem....getting the drill to drill the hole(s) EXACTLY where I want it! Any further suggestions are anxiously awaited!!

Warren Kaplan
Sine Qua Non
CD27
Oyster Bay Harbor, NY

[Larry DeMers]

Hi Warren,

Agree, it's a lot more to drill through S.S. than hard steel! I usually make a small center point with a small point center punch, then start with say 1/8 in. cobalt, and running at half speed or less, and a little puddle of cutting oil (high sulphur content), drill with an even pressure..do not horse that sucker, or it will break thru the back side and jamb up, breaking the bit off.
Next go up another small increment in size..goes MUCH easier this time. Sneak up on the final size with say three steps. The larger the drill bit, though, the more important it is to not use too many steps or the center hole will be too large to guide the final sized drill bit well. It will then want to wander in the hole. So if you had a 7/16 in hole to drill, try 1/8", then 1/4", then the 7/16".
As you know, go slow and keep even pressure and angle on the gun. Extreme pressure will dull the point quickly.

Cheers,

Larry DeMers
s/v DeLaMer
Cape Dory 30
Lake Superior

I had to put some holes in a stainless steel halyard organizing plate that will go beneath my mast step. I'm learning some "hard" lessons along the way. Project ain't quite finished yet either. I read up on drilling stainless before I started but I didn't do everything they suggested. I should have and I will when I "press on" with the project.
First, stainless, depending on its grade, is very hard. You need to use cobalt or titanium bits or maybe carbide will do. Because stainless is so hard, when starting the hole, the bit tends to "walk" away from the mark. This creates all kinds of problems when you have to drill holes spaced exactly (like exactly below the holes in the mast step). That's where I screwed up and when I placed the mast step over one hole in the plate, all I saw was half a hole below another mast step hole. Lucky for me I can just shift the plate a little and start over again. Use a center punch to mark your spot. Drill a pilot hole of smaller size first! Use LOW SPEED for drilling stainless. Heat generation is anathema to stainless. It can crystalize it, so I've read, and make drilling harder. It also ruins the drill bit. So go slow! Use cutting oil! I don't know exactly what makes an oil "cutting oil" but I will find out. The oil not only lubricates, but like in an engine, it cools the work which is important. I tried to do this with my hand held drill. Because of the bit walking, it makes accurate drilling very difficult. It also requires alot of pressure. The organizing plate isn't on the boat yet so I can take it to my shop (read basement). I think the most important thing in all this is to do this on a DRILL PRESS. I'll clamp the work down. Accurately mark where the holes should be and I won't have any trouble with the bit slipping an 1/8" making the hole useless. I think that's the biggest problem....getting the drill to drill the hole(s) EXACTLY where I want it! Any further suggestions are anxiously awaited!!

Warren Kaplan
Sine Qua Non
CD27
Oyster Bay Harbor, NY

demers@sgi.com

[Warren Kaplan]

Like anything else, having the right tools to do the job is worth the money. The difference in results when trying to drill accurate holes in stainless steel between using a drill press versus using a hand held drill is akin to the difference between chicken salad and chicken s--t! Cobalt bits and marvel mystery oil as the cutting oil made the job go very smoothly without having to use extreme pressure. The holes in the organizing plate line up perfectly with the overlying holes in the mast step. It almost looks as if they were drilled at the same time. So, if you can, if accurate holes are needed in "hard to drill" surfaces, take the work to a drill press. It sure saves ALOT of frustration and may also save you mucho money and time by NOT ruining the work!

Warren Kaplan
Sine Qua Non
CD27
Oyster Bay Harbor, NY



Setsail728@aol.com

[Scott Sirgo]

Try using MOLY-DEE. It is a tapping fluid formulated with Molybdenum Disulfide. Your tooling will last longer and the cutting and tapping will be much easier. You can get it from industrial supply houses such as Grainger or McMaster Carr.