Drilling

[RobTech]

I'd like to hear from the veterans here, some tricks and tips for drilling thick plate.

I recently had to drill 1/4" plate SS up to 1/2" hole that was serious to get through. I finally had to drill about 6 holes on each one, coming up a few sizes every time. The way I was taught, from my dad at least, was slow and oiled. That's the method I've used all my life and it's served me well. Maybe my issue was just this piece?, it sure was hard!

Here's a few pics:




THANKS!

[Country Metals]

1/2" hole in 1/4" S/S I would get it punched from the steel yard or I have some really good bits that I just use straight. I run the speed down to about 500 and oil constantly.

[ducer jake]

I would use a 130 to 135 degree split point. Preferably cobalt but HS will work.. As for the pilot hole, 1/4" should work fine after the countersink. Low cutting speed with a high feed. I like using castrol molly dee tapping fluid for my hard to drill parts, its just kinda hard to clean prior to welding, specially tig but it works wonders. other than that, a good solid drill press or mill. If your machine has power feed i would run around 180 rpm at .006"/rev. (for the 1/2) Hope i could be of some help.. good luck

[walker]

I don't do enough SS to remeber between times, but some alloys are soft and drillable, and some are hard. There are others that will work harden as you are drilling them. So, let us know what alloy it is, and you may get some more usefull information as to rpm and feed, as well as what bits are going to work better.

[snowbird]

slow rpm is a must, les than 200... feed it harder than steel and most important
use a cutting oil specially made for stainless.

i use a cutting oil from walter for stainless (the bottle is out of reach for now)
and tried few other types or brands, nothing works like it, turns stainless into aluminum...ok ok...well close to...

last job i did were 1/2 holes in 1/2 thick s-304 did them in one pass went very well. can't tell if residues are welder-friendly .

[ducer jake]

http://www.custompartnet.com/calcula...speed-and-feed

[mhancox]

A Iron worker machine would be alot easier. If you have access to one.

[RobTech]

THANKS everyone for the help!

So, let us know what alloy it is, and you may get some more usefull information as to rpm and feed, as well as what bits are going to work better.

Sorry, it's 304

A Iron worker machine would be alot easier. If you have access to one.

I can only wish I had access to one

[Paul Seaman]

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.

[Architect-1]

TAP MAGIC

The best cutting fluid in the world!

Try it.