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Drilling the auger motor shaft to accommodate a new auger with cotter pin?

Post in 'The Pellet Mill - Pellet and Multifuel Stoves' started by Don2222, Nov 23, 2012.

  1. Don2222

    Don2222 Minister of Fire

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    Hello

    The new auger I got has a hole and cotter ping. Has anyone successfully drilled a hole through the case hardened tool steel auger motor shaft? It is very hard!

    I hear this 1/8" inch diameter 118 degrees carbide tipped die drill like this is needed? $11.23
    http://dewitt-tool.com/dadie18diedrills.aspx

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  2. SmokeyTheBear

    SmokeyTheBear Minister of Fire

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    That is what jigs, clamps, and a drill press are good for.
    343amc likes this.
  3. MountainSean

    MountainSean Credo Quia Absurdum

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    Yep. Nice drill press with an industrial diamond drill bit. Goes through hardened steel so nice.
  4. Don2222

    Don2222 Minister of Fire

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    Hi Mountain Sean
    Why do most diamond bits like this 1/8" state only for tile and glass? $7.75 is more in my budget.
    http://www.discountdiamondbits.com/18quot-diamond-drill-b18.html

    Would this for $50 for a .122 inch work better. 0.122 is little smaller that the 0.125 1/8" I need and out of my budget.
    http://www.ukam.com/diamond_solid_thin_drills.htm

    Do either of the above do case hardened tool steel also?
  5. pell it

    pell it Feeling the Heat

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    Order a motor from USSC for the 5660. It will have the hole in it already!

    The case hardening is only a few thousandths thick. If you properly fixture the shaft on a drill press, as previously stated, just use a couple HSS drill bits. One to get thru the case hardening (re-sharpen or dispose of after) and one to finish the job. I am surprised the shaft is case hardened and I doubt it is tool steel. If it is through-hardened tool steel, Carbide is your best bet.
  6. pell it

    pell it Feeling the Heat

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    Another tip is to kiss the shaft with a grinder where you want to start the hole. This will remove the case hardened skin and expose the softer steel below.

    BTW What diameter is that motor shaft?
  7. jtakeman

    jtakeman Minister of Fire

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    I'm with pell it, Carbide all speed, little pressure(or it crumbles) with some lube. Cobalt will also work and is usually easier to find.
  8. MountainSean

    MountainSean Credo Quia Absurdum

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    I was just reminiscing back to my childhood days working with my grandparents in their machine shop. Nice bank of 3 drill presses with various bits for drilling through hardened steel, plate steel, or cast iron or ceramic. Pretty much whatever they needed to drill through to make whatever tool they happened to be making. I didn't mean for it to be taken as a suggestion and apologize for any confusion there.
  9. Don2222

    Don2222 Minister of Fire

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    Interesting. So I just ordered a 1/4" and 1/8" Carbide Tip drill bits. Always learning something new!
    The 1/4" is for drilling out the set screws so I can reuse the auger. The 1/8" is for the cotter pin,

    According to dewitt the Carbide Tip Die drill bit is better for hardened steel.
    "Run at 75 to 100 surface feet per minute with steady hand feed. It is a good pratice to clear the drill from the hole to allow coolant to wash away the chips. Designed for drilling hardened steels in the range of 45-65 Rc. Note: Sizes under 11/64" are sold carbide spade construction"

    The full 100% carbide drill bit is better for Iron and what not.
    "Solid Carbide drills are designed for drilling abrasive materials when drilling accuracy must be maintained and/or when used in high temperature drilling applications. Solid Carbide drills are used on materials such as cast iron, non-ferrous alloys, high silicon aluminum, copper, plastics, bronze, hard rubber, plexiglass, and other similar materials"

    http://dewitt-tool.com/
  10. jrsdws

    jrsdws Feeling the Heat

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    100sfm for your 1/8" carbide tip drill is about 3000rpm.

    Fixturning is most important. When drilling out a pre-existing hole, your bit will have a tendency to want to bind as it's not cutting from center as designed.

    Make sure you have everything aligned perfectly and locked down tight. The case hardened skin will likely chatter and chirp and might really damage that tip, but then will go through the rest easy if it lives. Increase feed pressure to engage it harder if it starts to chatter.
  11. jrsdws

    jrsdws Feeling the Heat

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    I should add that as a machinist for 25yrs....I don't believe the 75 to 100sfm is necessary nor ideal if you cannot provide adequate steady feed....which is near impossible by hand.

    Good alignment to the hole and great work holding with a firm steady feed pressure will be key to success.
  12. imacman

    imacman Guest

    x2
  13. Don2222

    Don2222 Minister of Fire

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    Attached Files:

  14. MCPO

    MCPO Minister of Fire

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  15. bonesy

    bonesy Feeling the Heat

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    I bought an after market auger motor for my BigE, don't need it yet but I noticed it does not have a hole in the motor shaft for the cotter pin that my existing setup has. Do you think this motor shaft will be hardened?
  16. ironpony

    ironpony Minister of Fire

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    tap the hole in the auger and add a set screw .50 cents
  17. Don2222

    Don2222 Minister of Fire

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    It is very hard! Hole should be min 9/64" or max 5/32" just order the carbide tip die drill bit and you will be all set!

    I also used a C-Clamp to hold the motor on the stand. It worked super!
  18. bonesy

    bonesy Feeling the Heat

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    Im getting a bench top drill press for Christmas so that'll be my first project with it.
  19. Don2222

    Don2222 Minister of Fire

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    Hey jmbones

    That's cool, here is the pic of the hole. I put oil on the shaft a couple times during drilling to keep it cool. Worked great!

    Attached Files:

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