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Thread: How to drill a hole "straight" through 15 inchs of wood

  1. #1
    Join Date
    Apr 2008

    How to drill a hole "straight" through 15 inchs of wood


    How can I drill a straight hole through 15 inches of oak/Poplar. It is laminated 1" X 3" boards. I tried a 24" long drill bit on my drill press. But it wouldn't go all the way through. I tried drilling by hand and the hole was not straight. I thought about getting a helper and on the drill press drill as deep as I can then slowly raise the table drill some more, raise the table drill some more etc. Not sure this is safe. Any thoughts? Thanks

    To Clarify, I am trying to drill a 1/2" hole

    Wood an Auger bit work better than a twist drill bit?
    Last edited by Joe Von Kaenel; 01-29-2012 at 3:26 PM.

  2. #2
    Join Date
    Oct 2007
    New Hill, NC
    Joe, if it were me I would build a fixture that clamped to the side of your 15" beam. The purpose of the fixture would be to house a couple of drill bushings in perfect alignment and perpindicular to the face of the fixture. I would probably install the bushings around 6" apart, which when coupled with your 24" bit should still provide you with adequate depth.

    Then I would use a long drill bit and hand drill, using the fixture to guide the bit.

    Here is an example of the type of bushing that I'm referring to:

    The fixture could be something as simple as a 4 x 6 that had the bushing holes drilled in it using a very accurate drill press.

  3. #3
    Join Date
    Jan 2008
    Warren, MI
    You don't say what size hole, or whether it needs to be round or not, but since this is a laminated piece, why not cut a 'square hole' the length of your beam on a table saw, or use a router to cut two half rounds, then glue it together.

  4. #4
    Join Date
    Oct 2009
    Morristown, NJ
    I'm not sure if this be any help to you, but it might be to some one else reading it down the line. I had a good success drilling 3/8" hole in 3/4" plywood to feed wires for under cabinets lighting using small metal lathe. I secured drill in the chuck, removed the tool slide and secured board to the saddle (by clamping it), feeding (drilling) was easy with cranking carriage handwheel. A very similar results can be achieved with wood lathe, by building a jig that would bring given board to appropriate height and be able to travel along the bed fairly firm and smooth. It would have to be fed (pushed) manually along the bed to complete the drilling.

  5. #5
    Join Date
    Jul 2010
    Northern Kentucky
    if your drill press is a floor model then it should be possible to drill all the way by raising the table but I would place a scrap piece of wood on the drill table to drill into when your bit break thru.
    If your drill table do not crank up then you could use two jacks [one on either side of the table close to the vertical post ] to raise the table even
    Last edited by ray hampton; 01-29-2012 at 3:23 PM. Reason: to add extra note

  6. #6
    Join Date
    Sep 2009
    Medina Ohio
    I would split the wood and rout a groove in each side.

  7. #7
    Quote Originally Posted by Joe Von Kaenel View Post
    I thought about getting a helper and on the drill press drill as deep as I can then slowly raise the table drill some more, raise the table drill some more etc. Not sure this is safe. Any thoughts?
    Since your drill bit is longer than the quill in your drill press, start with a shorter 1/2" drill bit and drill a hole as deep as possible. Then switch to your 24" bit, lowering your table so you can get the bit in the hole you started. Raise the able up so that the tip of the drill bit is just above the bottom of the bole. Start the drill and drill as deep as you can go. Lower the table to clear out the chips then raise it again repeating the previous process until you drill all the way through. Do not try to raise or lower the table while the drill is running. It will be easy to get it out of alignment where the drill may bind and possibly break.
    Lee Schierer - McKean, PA
    USNA- '71
    Captain USN(Ret)

    My advice, comments and suggestions are free, but it costs money to run the site. If you found something of value here please give a little something back by becoming a contributor! Contribute

  8. #8
    Join Date
    Dec 2004
    St. Louis
    Does your dp table tilt? If it does, clamp the block to the the table then using various length bits, gradually adjust the height of the table so you can drill all the way through. Make sure you lock everything but the head so you don't go off center. If you're sure you can keep the block centered, you could even swap it end for end and meet in the middle.

    A single flute auger bit might be the thing to use here. Maybe a spade bit.
    Where did I put that tape measure...

  9. #9
    Join Date
    Jul 2010
    Northern Kentucky
    drilling a hole this deep would be very easy IF you had a post drill

  10. #10
    Join Date
    Aug 2011
    Ship auger bits are made for this type of work, the lens is extra wide to guide it straight and true:

    • Single cutter and side lip effortlessly bores holes in wood where nails may be encountered. Cuts through nails without damaging the bit
    • Full-length heat treatment guards against bending in heavy-duty applications and strengthens the twist where the greatest strain occurs
    • Hollow center flutes clear chips quickly out of holes
    • Wide lands help keep bit straight as it bores
    • Medium-fast screw point ideal for general woodboring applications. Bit can be resharpened

    - Beachside Hank

  11. #11
    There are several good suggestions above, you can follow through on them depending on how accurate and straight the hole needs to be.

    First off, you drill from both sides. Accurately mark the hole location on both sides of the piece of work.

    Use a well sharpened auger bit. Timberframing speciality bits are best:
    Irwin type bits are fine.

    COLT Twinland Brad Point Bits:
    are nice, may not be long enough.

    The most accurate hole will come if bushing guided from both sides.

    Use a bit long enough to go past halfway, but not too much longer.

    Using a speed square, or two, lined up adjacent to the bit, will greatly help you eyeball it in if drilling freehand.

    Start the hole, drill in and inch or so and check your alignment. A helper is useful.

    Mark the bit an inch or so past half way, drill down, remove the bit from the hole and drill from the other side.

    Use a powerful drill motor. BE CAREFUL! a big drill motor can twist you up badly, very quickly!

    By drilling from both sides, you minimize the consequences of inaccurate alignment. The fastener, wood or metal will follow the hole.

    Ream the hole with a full length bit iffen you so desire.

    Ask if you have any questions.


  12. #12
    I'm with Ray,
    That's the way to go, router & a round over bit - pick your size, set your fence, your good to go and just glue them back together....

    It will turn out very nice IMO...


  13. #13
    My 2 cents. Your problem is not necessarily the length of the drill bit or the type of drill. What you want is for the drill bit to emerge from the opposite side of the beam in the desired location. This is dictated by the drill passing through the wood perpendicular to the side and not wandering or bending. I would approach the problem by using a drill press to accurately start the hole in a perpendicular direction. You can use a short drill bit to start the hole, but switch to a longer one once you reach the limit. In order to maintain the direction, I think you need to use a drill guide of some sort at least equal to half the length of the drill, else you can wander off course. You can make this with a router, cutting a groove in a block and then sandwiching a flat, uncut half to the grooved block. Use long clamps to hold this to your beam. Cut the block, or use shorter guide blocks once your hole advances. Use a 1/2" rod to line up the guides and the hole when changing guides. As mentioned above, 1/2" drills can hurt you badly if it grabs in your work, so use sharp bits. There are drills that will stop drilling, mechanically or electronically, that are worth looking into.

  14. #14
    Join Date
    Aug 2011
    NW Missouri, USA
    Just a little theory on deep drilling. Straightness is attained by starting in exactly the right direction and the drill being full sized and rigid for some distance behind the cutting end. The shank rubbing against the bore guides the tip. A spade bit or a forstner with a long extension won't achieve this. It is possible to screw an auger into the work piece permanently. I know. I would likely clear the chips and lube the shank with paraffin often.

  15. #15
    Join Date
    Aug 2009
    'over here' - Ireland
    Hi Joe. I've no experience, but suspect from experience with less ambitious jobs as some of the others have implied that quite apart from coming up with a set up to drive a drill that long you could also run up against the fundamental limits inherent in a 1/2in drill too - insofar as keeping it straight over that sort of distance is concerned. No doubt the type of wood, feed rate, drilling technique, it's grain and the type of drill will make difference too.

    Routing before gluing sounds attractive, you cold always run a drill through it afterwards to clean up the hole and get rid of any glue dribbles and the like...


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