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How to sharpen drill bits by hand

Discussion in 'The Tool Shed' started by mofugly13, Jan 19, 2007.

  1. mofugly13

    mofugly13 1 ton bucket of rust Premium Member

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    Maybe someone could make this a sticky?

    Here is a great written description on how to hand sharpen drill bits. This is how I do it. I used to frequent the shooters.com gunsmithing forum when shooters was stil around, teenut was as regular there as 'fumes is here. I learned a LOT from him on that site. RIP


    DESCRIPTION:
    This is a copy of instructions for hand sharpening drill bits as
    originally posted in rec.crafts.metalworking by Robert Bastow (teenut).
    Posted by Ted Edwards <Ted_E@bc.sympatico.ca>. Ted provided the
    following description:
    ================================================== ===============
    I just posted Teenut's description of how to sharpen a drill by hand
    to the dropbox.
    Ted
    ------ Teenut's instructions ----- Anyone who wants to learn this skill should start large - and I mean
    1/2 inch and above. This is a great way to make long drills short.

    I believe I learned on a 3/4" taper shank drill..it is a lot easier to
    see all the angles and begin to understand how they work and interact.

    By the way..we had a handy little dohickey to help get the drill lips
    level. I have never heard it described before..

    For the morse taper shank drills from 1/4" up to about 1" diameter, we
    had a piece of 2" by 1/8" hot rolled steel strap..about 14" long. One
    end was bent at right angles, about 2" from the end to form an L shape
    with one 12" upright and a 2" horizontal. In the geometric center of
    this short leg was afixed a "dead" center..not a lathe tailstock
    center!!...more like a 1/2" bolt, 1/2" long, turned or ground to a 60
    deg point (Approx...no great precision required) and screwed in from
    the under side. Thats IT..toolmaking over!

    In use the inner face of the upright was coated with whitewash (Never
    SAW marking blue 'til I got in the toolroom!) The drill was ground,
    freehand, on the FACE of the wheel (not the flat side)...care being
    taken to keep the POINT angle as equal as possible on both sides..I'll
    tell you how to do THAT in a moment..

    Lets do that now in fact..

    Jim, You are dead right about not being able to grind a drill without
    mechanical help! Well here's how you create your own "6 Million
    Dollar Bionic Darex" ;^)

    Let's assume we are going to sharpen a 3/8" diameter, 2MT shank
    drill..it is about 8" long (these figures are arbitrary..I just want
    every one to have the same mental picture of what I am describing. We
    approach the wheel, which has been dressed on its face, dead straight
    across with no grooves..(Ve SHOOT anyone ve catch putting grooves in
    ze drill wheel!!..No Pity..No Prisoners..Ya! Verdampt!)

    (Sorry)...

    The drill shank is held firmly in the RIGHT hand...ALL the movement
    and control is imparted by the RIGHT hand. For the purposes of drill
    grinding, the left hand could be...with benefit..a LUMP OF CLAY!!

    It is from this "lump of clay" that we fashion the Bionic Darex".

    Place your left hand thumb and forefinger tips LIGHTLY together..Relax
    the other three fingers and let them naturally curl against the palm
    of your hand. Let the drill flute drop into the vee between thumb and
    forefinger and let the tip of the finger "Find" the curve of the flute
    where it fits comfortably. The tip of the thumb rests on the sharp
    junction ot the land and the flute, about an inch back from the drill
    tip.

    Now...SQUEEZE HARD!!! YOUCH!...I said it would be easier if it were
    clay! 8^) Lift the drill from your fingers...see the GROOVE?...Drop
    the drill back in..it locates within a thou or two! Magic?..Bionic at
    least! Squeeze again to set the groove. You have created a
    customised drill guide that fits better that that on any machine ever
    built! You can relax your grip now..feel how smoothly the drill will
    ride back and forth, guided by the groove you have created for it.

    Place the knuckles of your left hand, LIGHTLY on the ginding wheel
    tool rest, and swing the drill shank, from left to right (using ONLY
    your right hand) and push the drill lengthways though that groove in
    your fingers back or forth using the groove to make the drill twist or
    "rifle" in your fingers. Do NOT move your left hand in any way..it is
    made of clay remember!

    UNTIL....

    A) The drill axis is "eyeballed" to be at half the required point
    angle to the wheel face...You can scribe or chalk reference lines on
    your grinder benchtop to help you line this up..at least untill it
    become almost second nature.

    B) The drill axis is dropped JUUUst below horizontal. This will
    ensure that your soon to be ground drill lip will start with a
    "smidgin" of cutting clearance.

    (Ideally, and certainly for a beginner, the grinder rest should be set
    dead radially to the wheel center and about half the drill diameter
    below the true center of the wheel)

    C) The two cutting edges of the drill..the straight, sharp bits,
    formed by the junction of the flute and the back face (the only bit
    you grind), should be horizontally disposed..with the edge uppermost
    on the side closest to your left hand..the other sharp bit of course,
    pointing downwards (Jeeze this would be a lot easier with a sketch
    pad)

    This I will call the SET or START position!

    NOW, move your left hand for the first, last, and ONLY time during
    this whole exercise. GENTLY ease the cutting edge towards the
    spinning wheel, carefully maintaining all the angles and orientations
    of the SET position..until the cutting edge is JUST shy of touching
    the wheel. If you listen carefully you will hear the tone of the
    entrained air, whistling through the narrowing gap. You will hear a
    subtle but distinct change of tone JUST, I mean Just...a couple tenths
    of a thou BEFORE the edge touches the wheel. STOP!!! FREEZE!! DO
    NOT MOVE!!

    Now, press the knuckles of your lump of clay..sorry, your left hand
    FIRMLY down onto, into and around the grinding rest..establish a
    "Groove" on the back of your hand as well as between your fingers.

    We are now ready to grind, Your left hand locked to the drill and
    grinding rest is otherwise quite relaxed..letting the drill slide,
    twist and tilt wherever your right hand and the groove in your fingers
    tell it to go.

    The actual grinding is a bit of an anticlimax.

    You have previously studied a new drill point, you have read about
    clearance, and cutting angles, and rakes and......

    With the RIGHT hand in control, gently, kinda, lean forward... bending
    or squeezing your arms hands and body..rather than actually moving
    them..untill you take up that last couple of tenths and the wheel
    begins to cut. Let it cut..don't force it, and don't rush it..it
    really won't hurt anything if you take a full minute per pass per
    face. YOU and your "Bionic Darex" are totally in control of that
    drill and the wheel..Forget the times when, close to panic, you swung
    the drill wildly past the wheel, hoping to get "the dirty deed" over
    with as quickly as possible.

    Take your time, enjoy the moment, THINK about the shape you are trying
    to generate. Just the one face is left to "Interpretation"...every
    other aspect,angle, facet, what have you...Has ALREADY BEEN TAKEN CARE
    OF!! and is locked in place under your control!

    The right hand should perfome a "Lower Quadrant sweep" for want of a
    better term. An observer behind you would see your hand move from
    about 17 minutes past the hour on a clock face, to roughly 25 minutes
    past. But it isn't a smooth arc of a circle, more a sector of an
    elipse..You see, as your hand starts to drop slowly, you are also
    rotating the drill in "the groove"..the first third of the turn needs
    to maintain that very slight clearance angle on the cutting edge, and
    not increase it too rapidly.

    You need the clearance to cut..But too much at that point will WEAKEN
    the edge, and cause the drill to snatch and chip...So the first part
    of the rotation is ALMOST but not quite, just as though you were
    grinding a straight cone point on the end of your drill. Only as you
    approach the second third, does your right hand start to noticably
    drop..kinda "Catching Up" on the rotary motion...increasing the
    clearance as it does.

    In the last third of the rotaion the right hand drops quite
    rapidly..Thogh not enough to catch the OTHER drill lip on the
    wheel..that lip is coming around quite rapidly by now.

    Above all, take your time, if it helps, move the drill one degree at a
    time, and think ahead what shape or angle the next degree of cutting
    face needs...Remember, you have control, and IT ain't going nowhere
    'til you decide.

    After a pass on one face, flip the drill in your "Bionic Darex" DO NOT
    MOVE THAT LEFT HAND!!, return to SET position and repeat, the pass on
    the other face.

    Having done a couple of passes on each face..it is now time to check
    the results on our homemade "Optical Comparator"

    (Sorry Jim I couldn't resist!!) ;^)

    Rest the center hole in back end of the drill shank, on the center
    point of the "Comparator" and use, first one and then the other drill
    lip to scribe a light line on your whitewashed (OK Blue or red dyed)
    surface.

    You will readily see if the lines coincide..if the lips are even..or
    not, as the case may be.

    Lets assume they are..Now look directly DOWN on the end of the drill
    to check the clearances. HUH? How can you check radial clearance by
    looking it staight in the face? Surely you need to look at it
    sideways?

    Well no you don't...for once all those interacting and confusing
    angles and faces and clearances are going to work together in YOUR
    favor and make what could be a tricky bit of metrology..quite simple.
    While we are looking at the end of the drill, we will also check that
    the POINT ANGLE is correct too!!!

    (Ok guys, leave quietly..teenut has finally lost it!!)

    No really, trust me. IF you look straight down on the point of a well
    sharpened, standard drill, you will see the two cutting edges, joined
    by the CHISEL edge which crosses over the web of the drill. The angle
    fromed by the chisel edge to each cutting edge should be ABOUT 50
    deg...anywhere between 40 and sixty is ok for a first attempt. (I can
    hear the purists and theorists screaming and lighting up their flame
    throwers.) But believe me, get it in that ball park and your drill
    will CUT. If the angle is too steep..you don't have enough
    clearance...negative clearance will give you an angle event greater
    than 90 deg. Too MUCH clerance and the angle will appear too shallow!

    While looking at the end, check the point angle, How? Look down the
    axis of the drill at the cutting edges. Are they straight? If so,
    your point is pretty close to the right angle (As designed for that
    drill, by its manufacturer when he set the helix angle and the cross
    section of the flute) If the edges appear CONCAVE the point is too
    flat and if they appear CONVEX, the point is too "Pointy"

    If your drill passes all these tests, which take but a second or two
    to perform, THEN IT WILL CUT..pretty close to size, without
    chattering, chipping, overheating, wandering or seizing. I guarantee
    it!

    Hey, thats a pretty good start for the first drill you ever ground!
    All it takes now is a bit of practice for it to become second nature
    and almost as easy with a little 'un or a big 'un!

    Hey guys!

    My apologies for "goin'on" but If it helps just one person to pluck up
    the couragre and go hand sharpen his (or her) first drill, by hand...

    Then I hope you will bear with me.

    It is late, I am tired and I am not even going to proof or spell check
    this,

    'night all

    teenut
     
  2. chevyfumes

    chevyfumes Court jester

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    Definately sticky this thanks Matt...
     
  3. tRustyK5

    tRustyK5 Big meanie Staff Member Super Moderator GMOTM Winner Author

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    Sticky...thanks Matt. :waytogo:

    Being able to sharpen a bit by hand is a very handy skill. I've done it at home using an angle grinder, but of course a bench grinder is a ton easier.

    Rene
     
  4. BlazerBud

    BlazerBud 1/2 ton status

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    An old Weldor taught me how to do this a very long time ago when he was teaching me. Basically, the idea is to put the exact same shape on the bit that it had originally and don't get it hot or it'll loose it's tempering. Most everything that I have ever drilled has been mild steel or 304 and 316 stainless. Using cutting oil and keeping the bit cutting while drilling keeps it sharp longer, it looses it's edge faster when you drill incorrctly. I usually only use high speed tool steel jobbers, and I have retempered some bits with a torch and then plunging them.
     
  5. blazin_blazer

    blazin_blazer 1/2 ton status

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    i'm glad i already know how to do this b/c that didn't make sense to me....alot of my drill bits are 1's people have used incorrectly and got them hot where they lost their temper and won't stay sharp...i'd take them out of scrap, grind the right angle and landings back on it, heat w/torch orange...not white hot, just pass cherry red to orange and dunk it in a bucket/bottle of oil until cool enuff to hold, let it air cool the rest completly...good as new!
     
  6. Blue85

    Blue85 Troll Premium Member

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    Anybody have a well-written version of this or some pictures?
     
  7. BlazerBud

    BlazerBud 1/2 ton status

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    Check out the following for heat treatment.

    http://tidewaterblacksmiths.net/2.html

    I saw Dave Smucker in person at one of my Blacksmith Meetings and he gave this same demo.

    As for grinding on the drill bit, you can hold it at the correct angle on a belt sander and then just twist it, but once you get it almost perfect, make sure that the leading edge bites a little.
     
  8. sweetk30

    sweetk30 professional hooker Premium Member

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    the newer drill doctors kick a$$ super easy to use and most people i know think thay are sharper than factory edge.

    best money you could spend for fast / easy / and it works !!!
     
  9. thatK30guy

    thatK30guy 1 ton status Premium Member

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    I use a Drill Dr. a lot at work. Can't mess up the bits if you know what you're doing. Sharpens them quick with precision. I'll never sharpen them by hand again.
     
  10. sweetk30

    sweetk30 professional hooker Premium Member

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    unless you try to make a right hand bit a left hand cause you grabed the wrong chuck. :doah: my old boss did that took him 10 min to figure out his mistake. fixed that dam left hand chuck with black marker ( left only ) :haha:
     
  11. 76zimmer

    76zimmer Flyin Rat Premium Member GMOTM Winner

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    which model did you get?
     
  12. thatK30guy

    thatK30guy 1 ton status Premium Member

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    Can't remember.

    Been too long since we bought it and I don't pay attention to any wordings/numbers on it anymore. Just use it and get busy with the bits.

    Will check when I go back to work Monday....if I remember. :whistle:
     
  13. sweetk30

    sweetk30 professional hooker Premium Member

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    around 2 years now thay got 10x easyer to you than the first style.

    get dull bit.

    pop in chuck head.

    set in side hole to get bit at right depth and twist position.

    clamp tight and remove chuck with bit tight.

    turn on and do 5-10 revolutions and done.

    when you do a few and use to the machine around 30-40 sec setup time and 1 min or so sharpen time. its just that easy. :waytogo:

    edit : link http://www.drilldoctor.com/ i have used the 500x model.
     
  14. thatK30guy

    thatK30guy 1 ton status Premium Member

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    Exactly how I do the one we have at work.

    Quick!
     
  15. 76zimmer

    76zimmer Flyin Rat Premium Member GMOTM Winner

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    Just found a brand new one for 100$ shipped...DD500X
     
  16. sweetk30

    sweetk30 professional hooker Premium Member

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    were smart a$$ ? mabye i want one :sign22:
     
  17. 76zimmer

    76zimmer Flyin Rat Premium Member GMOTM Winner

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