Miller Electric

Welding Discussion Forums

Home » Resources » Communities » Welding Discussion Forums

  • If this is your first visit, be sure to check out the FAQ by clicking the link above. You may have to register before you can post: click the register link above to proceed. To start viewing messages, select the forum that you want to visit from the selection below.

Announcement

Announcement Module
Collapse
No announcement yet.

Drilling

Page Title Module
Move Remove Collapse
X
Conversation Detail Module
Collapse
  • Filter
  • Time
  • Show
Clear All
new posts

  • Drilling

    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!

  • #2
    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.

    Comment


    • #3
      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

      Comment


      • #4
        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.

        Comment


        • #5
          drilling stainless

          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 .

          Comment


          • #6
            try this speed and feed cac

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

            Comment


            • #7
              A Iron worker machine would be alot easier. If you have access to one.

              Comment


              • #8
                THANKS everyone for the help!

                Originally posted by walker View Post
                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

                Originally posted by mhancox View Post
                A Iron worker machine would be alot easier. If you have access to one.
                I can only wish I had access to one

                Comment


                • #9
                  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.

                  Comment


                  • #10
                    Two Words......

                    TAP MAGIC

                    The best cutting fluid in the world!

                    Try it.

                    Comment


                    • #11
                      Cutting Fluid

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

                      Comment


                      • #12
                        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.

                        Comment


                        • #13
                          Originally posted by Paul Seaman View Post
                          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!!

                          Comment


                          • #14
                            Originally posted by Ronnie View Post
                            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

                            Comment


                            • #15
                              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

                              Comment

                              Working...
                              X
                              Special Offers: See the latest Miller deals and promotions.