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Drilling through hardened steel

Discussion in 'The Hokey Ass Message Board' started by 1oldtimer, Nov 18, 2011.

  1. flynfrog
    Joined: Sep 19, 2009
    Posts: 68

    flynfrog
    Member

    one thing not mentioned here is you need a lot of tool pressure. You said you polished the holes. This means you just work hardened it and now its even worse probably drilling to fast and to light of a cut . I prefer tin coated cobalt very slow speed and lots of tool pressure. You want one long chip coming off the cutter.
     
  2. Engine man
    Joined: Jan 30, 2011
    Posts: 3,480

    Engine man
    Member
    from Wisconsin

    I use cheap masonry bits and use a 4" grinder to sharpen them. Try Fastenal for a carbide bit or a good HSS bit and you need to apply lots of constant pressure. A drill press works best. I've drilled forklift tines with good HSS bits.
     
  3. kiwiandy
    Joined: Apr 19, 2005
    Posts: 419

    kiwiandy
    Member

    Im not sure what a drill doctor is but either way a fine silica carbide wheel (usually green) works well to sharpen solid carbide bits.
     
  4. Hey Dan, My 55 F100 had a safety latch....are you missing this?
     
  5. burl
    Joined: Nov 28, 2007
    Posts: 840

    burl
    Member
    from Minnesota

    Could be drilled with colbalt but i would use a solid split carbide drill.Chucking in a vise in a mill would be the best way.We do this all the time and the key is to have a sharp drill and use the quill stop for just thumbing down a little at a time to control the cut.Also use a good air blast to remove the chips.You asked for the best way but this would require somebody with a mill or a drill with some quill control.
     
  6. Hey Mike, I have the safety latch but a lot of people keep telling me horror stories about the hood turning into a sail on the freeway even with the safety latch. I was just looking at making an extra safety set-up with the added insurance of a hood lock, without altering the panels or looks.....since I had the grille area apart to paint it. This is the latch pin I'm trying to drill though.
     

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  7. That's what I was trying to avoid, I guess I'll ask the machine shop guys tomorrow....I hate doing that because we're not allowed to do our own projects.
     
  8. jrodmc
    Joined: Apr 13, 2009
    Posts: 8

    jrodmc
    Member

    houge mag drill with houge bit.
     
  9. If you were close by, I'd say c'mon over and we'll tackle it. You really should have it in a solid vise and drill with something you can control the RPM.

    The standard RPM formula is: RPM = (cs x 4)/D.

    cs = cutting speed of the material, I'd go conservative and give yours a 30.

    4 = a constant, I've seen 3.87 used, but 4 is close enough.

    D = the drill diameter, you said a 1/4".

    So (30 x 4)/.25 = 480 RPM

    Spot the hole with a center drill first. You might want to use a smaller drill (like 5/32") first then open it up to the final size. Of course use some sort of coolant. I use water soluble, but a thicker mix for jobs like yours. If you can dig one up, go with a TiN coated drill and peck at the hole, maybe a 1/16" at a time until it breaks thru.

    Bob
     
  10. Ok, I got it.......I was lucky and it was only case hardened. I went slow rpms, lot's of cutting fluid and lot's of down pressure in a drill press with a vice. I only wasted 1 bit :), then put in a new bit and started again. Maybe a 1/4" in and it started cutting like normal steel.

    Thanks again everyone.
     
  11. kevin mac
    Joined: Feb 21, 2007
    Posts: 106

    kevin mac
    Member
    from toledo,oh

    sounds like you picked up some old bed frame angle...:confused: i drillit after i have heated it cherry red for a while... let it cool before attempt. get some cutting oil on it also. drill SLOWLY. start with smaller size for pilot. then regular size....step by step -slowly we creep......k
     
  12. That piece looked as if it may have been case hardened, too lowly a part to go with something that hard of a material when a simple batch hardening process would do the job.

    I'm glad you got "through" it.

    Bob
     
  13. Lockman1
    Joined: Jan 4, 2014
    Posts: 1

    Lockman1
    Member

    RHC - Rockwell Hardness C

    HSS Drill Bits - Work well up to the 50ish RHC
    Drill - Mild steel, Some tool steel, Some Spring Steel
    No Drill - Hard Plate, Anti Drill Plate, 404c Stainless Steel
    Pro - Good in Hand Drills and most drilling applications
    Con - Has limitations in hardened steels

    Cobalt - Works up to 58ish RHC
    Drill - Mild Steel, Some Spring Steel, Some Tool Steel
    No Drill - Hard Plate, Anti Drill Plate, 440C Stainless Steel
    Pro - Good for hand drills and most drilling applications
    Con - Has limits with hardened steel

    Carbide Tipped - Will drill almost any steel, Hard, Stainless or Mild.
    Pro - Drills all steel
    Con- Blunt tip requires extreme pressure to produce cuttings. Drill bit is hard to start on all steels.

    Diamond Coated Drill Bit - Cuts on most steels(Not Hard Plate) just not for long.
    Pro - Will Drill most steels (Not Hard Plate)
    Con - Cutting stops quickly after diamond grit has warn off, Then behaves like HSS bit

    Solid Carbide Drill Bit - Cuts all steels.
    Pro - Sharpened points wont "walk" like carbide tipped bit. Cuts all steel
    Con - Sharp tip and fine edges can chip easily and ruin drill bit. Not for hand drills. Expensive!

    For more information enter “The Ultimate Guide To Drill Bits” ____ Tube video into your favorite search engine and watch the video.
     
  14. gatz
    Joined: Jun 2, 2011
    Posts: 1,817

    gatz
    Member


    I think you mean Hi Roc...just google it.
    These are solid carbide 2-flute (typically) drills that are used for hardened steel. Sometimes it is necessary to drill holes in hardened steel "after the fact"
    These drills can be used on hardened steel up to ~60Rc. Best to use in a milling machine, and gradually lower the spindle by using the quill stop....maybe .010/.020 at a time....kinda like peck-drilling.
    Coolant helps.

    I've drilled through the casehardened surface of some Thomson bearing shafts which are at about 62Rc. Once through the case, it's better to use HS steel bit, because the inner core is not hardened. When the opposite side was reached with the HS, the shaft was turned over (properly located) and the hole was finished with the Hi Roc
     
  15. Rusty O'Toole
    Joined: Sep 17, 2006
    Posts: 9,657

    Rusty O'Toole
    Member

    Anyone heard of drilling leaf springs using Elmer's Glue as a cutting fluid?
     
  16. Engine man
    Joined: Jan 30, 2011
    Posts: 3,480

    Engine man
    Member
    from Wisconsin

    Yes I've used Elmer's in a pinch. Again, when drilling hard material, a drill press or mill is needed to get down pressure. On one occasion, I did drill a main leaf in a pickup truck in the vehicle by setting the drill on a rubber mat on the floor and lowering the spring onto it to provide pressure. This requires a drill with a D handle that will sit straight.
     
  17. eicke
    Joined: Jul 30, 2012
    Posts: 63

    eicke
    Member

    I was surprised on how easily leaf springs drill if you know what your doing. With a VERY slow speed and ordinary bits, cutting oil and a press. Used multiple size pilots to drill a T spring for Teflon sliders, 7 leaves in about 2 hours. Key is keep the bits as cool as possible.
     
  18. redlinetoys
    Joined: May 18, 2004
    Posts: 4,302

    redlinetoys
    Member
    from Midwest

    Here is your answer...

    http://www.jalopyjournal.com/forum/showthread.php?t=672058&showall=1

    Post number 60. And, yes, my drill bit just danced around on mine too until I hit the center punched mark with a propane torch and heated it up. The drill bit then went through with no drama.

    The car has been assembled and driven for a decade since with no other wear or problems.

    Worked for me!!!!!
     
    Last edited: Jan 5, 2014
  19. redlinetoys
    Joined: May 18, 2004
    Posts: 4,302

    redlinetoys
    Member
    from Midwest

    A couple of quick pics...
     

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  20. redlinetoys
    Joined: May 18, 2004
    Posts: 4,302

    redlinetoys
    Member
    from Midwest

    And a repost of the original instructions...

    Here is something that might help in the future. Not sure if it will work on your latch (The following instructions are 55 Chev specific), but it will work very easily on many different cars and maybe could be adapted to yours.

    This was discussed some time back and resulted in several available aftermarket latches being suggested. I still may go that route in the future, but in the meantime I have come up with an extremely simple surefire way to keep an original hood latch from letting go.

    I was not overly concerned about this until an extremely hard second gear shift popped mine open (Thank God the safety caught it from coming up all the way.

    Anyway, the fix for my 55 was very simple. Simply do the following:

    1. Shine a light up through the grill with the hood in the down and latched position.

    2. You should be able to see the first catch sticking through the receiver and off to the left (The safety catch is on the right side).

    3. Take a fine line marker and mark a line on the catch itself as close as possible to the center hood latch post (the permanent protruding center part on your hood latch).

    4. Take the latch off of the hood to your workbench.

    5. Center punch a mark right on the magic marker line, dead center on this left side catch (top to bottom). The idea is to create a hole that can be pinned so that the catch cannot recede back into the latch mechanism (behind the center post of the latch).

    6. Drill a 5/32 or 3/16 hole in this area. The latch is hardened. A little heat will greatly assist the drilling. Just let it cool back down slowly to retain some hardness.

    7. Put the latch back in the car.

    8. Shut the hood and look back through the grill. You will be able to see the hole just appearing on the catch and will be able to see that a pin through this hole will keep the catch from retreating.

    9. Go to your local tractor supply and spend $1.59 on a hair pin clip (5/32" x 3"). This looks somewhat like a regular hood pin clip but is designed for tractor pins that are 5/8" to 1" in diameter.

    10. Add a small 1/2" long piece of vacuum line on the wavy part of the pin to avoid any rattling and then slip the pin through the hole from the front of the grill.

    You can just barely see the pin if you are looking for it. A little black paint would make it invisible. If you pull the latch to open the hood, you will find that the latch will not pull at all and the hood will refuse to open.

    It takes a little dexterity to slip the pin in and pull it out, but it is snug and works well.

    No more worries. Worked for me!!!
     
  21. belair
    Joined: Jul 10, 2006
    Posts: 9,013

    belair
    Member

    Good tip,redlinrtoys
     

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