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Drilling Stainless Steel..?

Discussion in 'The Hokey Ass Message Board' started by Plymouth, Jan 31, 2011.

  1. Plymouth
    Joined: Jan 8, 2008
    Posts: 211

    Plymouth
    Member

    I have a small visor accessory I wanted to reposition the hold down metal part.

    The clip on it must be stainless steel I only need a 3/16 or smaller hole in it BUT boy is it hard to drill

    Should I just use a center punch and make a hole then use a drill or is their a another way to drill this thanks for the info..
     
  2. Any good sharp drill will drill a piece of stainless a few times before it dulls. If possible try cobalt drill bits.
     
  3. roadworthy'49
    Joined: Apr 17, 2010
    Posts: 173

    roadworthy'49
    Member

    start with a smaller bit first, and make sure it's very sharp... even slightly dull bits have a hard time in stainless
     
  4. Rolleiflex
    Joined: Oct 25, 2007
    Posts: 1,042

    Rolleiflex
    Member

    Use a center drill first, that way you won't have the drill bit walking all over the place.
     

  5. BillM
    Joined: May 26, 2007
    Posts: 247

    BillM
    Member Emeritus

    Use a sharp drill and push firmly on the drill motor; don't let the bit spin on the stainless, it will just get hot, dulling the bit and work hardening the stainless which makes it even tougher to drill. A little cutting oil will help too.
     
  6. rustyford40
    Joined: Nov 20, 2007
    Posts: 2,168

    rustyford40
    Member
    from Mass Bay

    Drill at a slow speed.
     
  7. Francisco Plumbero
    Joined: May 6, 2010
    Posts: 2,531

    Francisco Plumbero
    Member
    from il.

    A good cobalt drill bit is best, low speed.
     
  8. jcmarz
    Joined: Jan 10, 2010
    Posts: 4,633

    jcmarz
    Member
    from Chino, Ca

    Cobalt drill with cutting oil or grease. Helps if you have a drill press.
     
  9. brad chevy
    Joined: Nov 22, 2009
    Posts: 2,627

    brad chevy
    Member

    Center punch,cobalt bit,slow to medium speed and don"t force it.
     
  10. havi
    Joined: Dec 30, 2008
    Posts: 1,875

    havi
    ALLIANCE MEMBER

    [​IMG]
    +1 If ya got one.
     
  11. Deuces
    Joined: Nov 3, 2009
    Posts: 19,937

    Deuces
    Member
    from Michigan

    Yep! I got me a set of those... :) Including some micro tips for my pin vises..
     
  12. mark phoenix
    Joined: Jan 15, 2010
    Posts: 38

    mark phoenix
    Alliance Vendor
    from wisconsin

    x-2 sharp bit ,, steady pressure ,, a little oil or cutting fluid
     
  13. Engine man
    Joined: Jan 30, 2011
    Posts: 3,476

    Engine man
    Member
    from Wisconsin

    Instead of using a conical point center punch, grind 4 sides on it so the point is pyramid shaped. A lesser bit sharpening angle helps too. 130-135 degree angle, low speed, lots of coolant or air and enough pressure to maintain a steady chip.
     
  14. Sheep Dip
    Joined: Dec 29, 2010
    Posts: 1,572

    Sheep Dip
    Member
    from Central Ca

    They pretty much got you covered the only thing I can add for lubricant is you can use a 50/50 Rapid Tap and cutting oil mix....straight antifreeze...or bar soap they all work well on stainless
     
  15. gtkane
    Joined: Jan 25, 2009
    Posts: 327

    gtkane
    Member

    You can drill stainless? I've always burnt through it:D!
     
  16. CoolHand
    Joined: Aug 31, 2007
    Posts: 1,926

    CoolHand
    Alliance Vendor

    Stainless work hardens, so you have to take big bites with a sharp tool and always run it slowly.

    A good sharp stub length cobalt drill run very slowly with a high feed pressure is best. Lubricate it with heavy/dark sulfurized or chlorinated cutting oil (dark thread cutting oil works very well).

    It is very hard to run the drill slow enough with a hand held vari-speed drill motor. You never want more than 1/4 throttle at most, even on the super tiny drills.

    If you over speed it, the spot will turn blue and go hard on you. The only way out then is to anneal the spot with a torch, or step up to a carbide drill. Any further drilling in that spot (without annealing) using HSS or Cobalt HSS drills will only result in frustration and dull tools.

    If you aren't making big stringy chips, you are running the drill motor too fast. Slow down and press harder.
     
  17. Good advice here. One question, are you sure it is stainless? If it is chrome plated metal, then you have a different set of problems. Chrome is much harded than stainless and may need to be ground off before drilling.
     
  18. First off, get the RPM right or you'll burn up drills.

    RPM = (CS x 4)/D.

    CS is the cutting speed, use 50 for stainless, not knowing the alloy you have.
    D is the drill diameter, .187
    4 is a constant.

    Plug it back into the formula: RPM = (50 x 4)/.187 = 1069 RPM.

    You can center punch it, but use a small drill like an 1/8" to do a pilot. If you are using a center drill, they don't free hand drill so well, hold the piece in a vise. Do the whole thing in a vise if possible.

    For a few holes, WD40 works as a lube, so does house hold 3 in 1 oil.

    Bob
     
  19. Dustmite Dragster
    Joined: Apr 30, 2010
    Posts: 61

    Dustmite Dragster
    Member

    I used carbide tipped cement hammer drill bits in the drill Press! Cuts right through stainless! spring steel too!
     
  20. dirty old man
    Joined: Feb 2, 2008
    Posts: 8,881

    dirty old man
    ALLIANCE MEMBER

    One of the best lubricants for drilling SS or hardened stel is bacon grease or plain old lard. This comes from 40* years as a machinist.
    Dave
     
  21. cal1954
    Joined: Aug 1, 2008
    Posts: 107

    cal1954
    Member
    from Omaha, NE

    Half the speed and twice the feed.
     
  22. Curt B
    Joined: Oct 15, 2009
    Posts: 325

    Curt B
    Member

    Slow, fast, and 1/4 throttle can be defined differently by everyone however using the formula provided by Bobss396 will get it right every time provided the SFM is known for a given material. Here's a chart:

    http://www.melcut.com/ti_melcut/MelcutCat_32.pdf


    The chart states a cutting speed of 20 to 50 surface feet per minute in 300 series stainless so to be safe start at the low end. For example 20 X 4 /.187 = 427 rpm minimum and 1069 as a maximum @ 50SFM.



    "half the speed and twice the feed" is the general rule for reaming a pre drilled hole as can be found here:

    http://www.wisc-online.com/objects/MTL8202/MLT8202.htm
     
  23. nicksduce
    Joined: May 26, 2009
    Posts: 20

    nicksduce
    Member
    from indiana

    get a can of tap magic, use as coolant works wonders
     

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