Drilling

[Ranch Hand]

Tap Magic x 2. Been using it ever since my uncles taught me how to properly drill on the farm many years ago.

[Keith_J]

That looks like a 300 series stainless which work harden rapidly. If you don't keep the feed rate up so the chip removes the previously work hardened skin, you will burn bits.

But with high feed rates, you can snap the bits. So it is best to spot with a center stepped bit, then go up in 1/8" increments. Stainless also doesn't conduct heat well so keep speed in the lower range, using the bit circumference as the limiting factor.

Sometimes, you just have to stop and sharpen the bit. I had a miserable experience in getting a broken starter bolt out of a 6.2 liter GM diesel. Must have sharpened the bit 6 times before it was deep enough to grab with a reverse spiral extractor.

[Ronnie]

I use a mag drill when ever heavy is in the equation. I have drilled 3' holes in 2" thick material and hated it but the finish was nice. I use a water misable drill coolant or if out of position then I use Tap Heavy tapping oil its sticky and lubes well and sticks to the drill bit.

Mag drill with stainless would be a challenge!!

[Keith_J]

Mag drill with stainless would be a challenge!!

For 300 series, yes. Tack weld a block of ferritic steel on the stainless with 308/309 and go to town

[torch]

I drill the pilot hole with a bit that is the same size, or slightly smaller than the web of the final drill bit..Just 2 holes...I dont step up drill sizes in 1/8" increments anymore, although that is the way I origionally learned as well

[Architect-1]

I just drilled 4 3/8" holes into 1" thick steel in 6 seconds each (after setup) using tap magic. I was afraid of going faster because steel started flying everywhere! I also drilled 4 1/4" holes into 3/4" steel rod in 10 seconds each.

Side note: The drill bits I was using were bought at ace hardware for $5 for the entire set! Not great bits! I used Pro Tap.

Grainger sells it. Check it out at http://www.steco.com

I didn't step up or down or sideways.

Good Luck!

[makowicki]

304 isn't the worst.
I have a mill so thats were I would do it. Low spindle speed and lean on the feed. I use water soluble coolants in a mister. With a mill or very well clamped part in good drill press will save your drill bits. I have to drill all types of SS, inconel and some other great joys at work. Keep teh tool cool.

[Paul Seaman]

I have a 1/2" plate with a notch for the bit to fit through and it will clamp to a work piece with C clamps and do just fine. Also I have made a cut down Beam for using the mag drill as a drill press and it makes it a handy mobile drill press.

The mag drill is one of the simpliest and most usable with imagination it can be even a vertical boring machine, with care that is!

[RobTech]

BIG thanks to everyone for all the useful information.

Decided to give this stuff a try

[Architect-1]

Let us know how it goes. I have never drilled stainless steel that thick and would love to know how it does.

Architect-1