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Thread: Is this a facing issue? (boring)

  1. #1
    Join Date
    Jul 2018
    Location
    Maine, USA
    Posts
    5

    Is this a facing issue? (boring)

    Hi all, in the pic below, you can clearly see how my long hole boring job went...astray.
    This seems to be repeating itself, a few things come to mind that might be at play here.
    1) Bad job of boring
    2) Bad job of marking center(s)
    3) Workpiece wasn't faced accurately?
    Maybe both?
    Full disclosure: I've been relying on the facing that was done before it came to me...maybe that's dumb to do.. I don't have any specialised tooling to face: should I use my
    cut off saw?

    This is a 14" conical boring job done using this process:

    1) I mark the center of the piece using a metal ruler, my eye, & a drawn/marked "X" (I tried using a jig I bought for this purpose, but it didn't result in a dead-center mark
    when tested with a caliper)
    2) I chuck it up with a 4 jaw, and drill a pilot on the tailstock end using a center-drill bit(using a jacobs chuck)
    3) I increase the size of the pilot with a larger center bit
    4) I begin drilling with regular twist bits, starting at 1/2" diameter(for a short distance), then I start reducing
    the size of the drills until I come to to a 3/16" bit, which doesn't reach the end of the piece, simply because it's not 14"
    5) I reverse the piece, drill a pilot hole again, and drill with a shorter 3/16" bit till it meets the existing bore.
    6) After this "step-drilling" operation, I ream the bore smooth
    7) I turn down the body to round

    I actually didn't detect anything was amiss until I decided to saw the thing in half, and then saw what you see here.
    (attaching a larger version also)

    IMG_1112_smaller.jpg

    Thoughts?

    Kind regards,
    Rich
    Attached Images Attached Images
    Last edited by Rich Gouette; 12-02-2022 at 4:13 PM. Reason: left off info

  2. #2
    Join Date
    Sep 2015
    Location
    San Diego, Ca
    Posts
    1,647
    For long/deep holes, consider buying or making a "gun drill". (Google it). They are much more rigid than a regular twist drill.

    Also "pecking" (easier to do on a drill press than a lathe) may help.

  3. #3
    Join Date
    Jul 2018
    Location
    Maine, USA
    Posts
    5
    Quote Originally Posted by Brice Rogers View Post
    For long/deep holes, consider buying or making a "gun drill". (Google it). They are much more rigid than a regular twist drill.

    Also "pecking" (easier to do on a drill press than a lathe) may help.
    oh I'm familiar with gundrills fer sure.. not able to invest in those beasties at present..
    but thank you for the reply.
    Also, in my OP, I explain that I'm step-drilling(pecking), which is what those in the irish bagpipe building community call it..

    cheers,
    R

  4. #4
    Irish is alway spelled with a BIG I ! You gotta lotta apology notes to write to make this right ! They do not easily forgive a slight !

  5. #5
    Join Date
    Sep 2015
    Location
    San Diego, Ca
    Posts
    1,647
    Smaller dia. gun drills are available on ebay at reasonable prices. I've seen some from $12 to 30.

    Look up D-drill bits. Essentially a gun drill but with no hole down the middle. You can make your own. Here is a youtube video: https://www.youtube.com/watch?v=jlNxvnOxMCE
    The guy made a beautiful D-drill. I made one (10 mm) that was not nearly as pretty but worked okay. D-drills are known for being able to drill deep holes straight. If you need a source of a precision rod, pick up an used PC printer. at a garage sale or thrift shop. They typically have a couple of precision rods in them of about the dia. you seem to be looking for. For drilling wood, you can live without hardenable tool steel - - you'll just need to resharpen.

    Let me know if you think this might work.

  6. #6
    Join Date
    Jul 2018
    Location
    Maine, USA
    Posts
    5
    Quote Originally Posted by Brice Rogers View Post
    Smaller dia. gun drills are available on ebay at reasonable prices. I've seen some from $12 to 30.

    Look up D-drill bits. Essentially a gun drill but with no hole down the middle. You can make your own. Here is a youtube video: https://www.youtube.com/watch?v=jlNxvnOxMCE
    The guy made a beautiful D-drill. I made one (10 mm) that was not nearly as pretty but worked okay. D-drills are known for being able to drill deep holes straight. If you need a source of a precision rod, pick up an used PC printer. at a garage sale or thrift shop. They typically have a couple of precision rods in them of about the dia. you seem to be looking for. For drilling wood, you can live without hardenable tool steel - - you'll just need to resharpen.

    Let me know if you think this might work.
    Thanks much Brice.. I'm certainly familiar with gundrills, and D-bits.
    I made a D-bit, but pretty sure it needs an overhaul..
    I had no idea though, that a gundrill could be had for that little $.. I'll check it out, thanks.
    I'm familiar with the rods in the printers(I'm an IT guy)..very interesting idea there..
    I'll jot down these notes ...
    Kind thanks for the reply!
    ~Rich

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