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Thread: Making a Spade Bit

  1. #16
    Join Date
    Nov 2006
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    TX, NM or on the road
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    845
    Quote Originally Posted by Walter Mooney View Post

    I went to HF yesterday and picked up the type of saw mentioned in the reamer links. I'm going to give the reamer a try, but I REALLY like Larry's bit!
    When you turn your blank for the reamer, add on about an inch on the end with the diameter of the hole that you will start with. It will act as a guide to keep your reamer running true in the hole you are reaming.

  2. #17
    Join Date
    May 2003
    Location
    NW Arkansas
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    180
    Quote Originally Posted by John K Jordan View Post
    BTW, does your bit work the same drilling into the side of a board as well as directly into the end grain as in your picture? I find that hollowing end grain on the lathe is easier than cross grain.

    Also, it looks like the bottom is sharpened to cut. Did you drill the entire hole with that bit or first drill a hole by other means almost (forstner bit, etc) as wide as the bottom of the final hole? That might work well - a lot of people start their hollowing on the lathe like that to save a lot of time and effort.

    JKJ
    John, it drilled about the same in side grain as end grain. I drilled the hole with only the bit shown. No pre-drilling required.

    I was scared that it might chatter some so I made the cutting part out of 1/4 or 5/16" tool steel. With it being that heavy, sharp, and a slow speed it didn't have any tendency at all to chatter. I only made a couple of test holes before sending it off to the user so it may have behaved differently with other woods.
    Larry

  3. #18
    Join Date
    Sep 2016
    Location
    Modesto, CA, USA
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    9,876
    Easy enough to make a spoon bit or a D bit. But they will be slow cutting compared to a proper spade bit. You could get a metal working counter bore taper ground to the needed angle. Any chance your taper angle might be a standard machine taper. Like a morse taper, R8. 5C etc. If it is they make drills and reamers to make or clean up those bores.
    Bill D.

    On edit:
    R8 16.85 degrees
    NMTB 16.5943 degrees

    HSK 30 degrees

    Maybe have one of these reground/sharpened to 15 degrees.
    Last edited by Bill Dufour; 05-03-2017 at 8:45 PM.

  4. #19
    Seems like you're off and running in another direction, but thought I'd toss this in the ring - just 'cuz no one else has.

    With stock that's 6 x 12 x 3/4, it seems like it would fit in a 4-jaw chuck of a engine lathe. Pre-drill your hole to just under the final minor diameter with the tail stock; then cut the required taper with a standard tool post in the compound rest. Simple...?

  5. #20
    I haven't read all the responses but Carbide Processors sells router bit blanks that came to mind when I saw Larry's bit earlier in this thread.

    http://www.carbideprocessors.com/sou...er-bit-blanks/
    I make dirt out of woodworking tools.

  6. #21
    Join Date
    Jan 2009
    Location
    Williamsburg,Va.
    Posts
    12,402
    Don't use an ADJUSTABLE bit!!! They ALWAYS get OUT OF ADJUSTMENT and ruin the hole. They might work with a brace and bit,but an electric drill or drill press is too much for them,it seems.

  7. #22
    My choice of metals would be drill rod. Air or oil hardened. Easy to harden after you shape it.

  8. #23
    Join Date
    Feb 2003
    Location
    McKean, PA
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    15,593
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    Quote Originally Posted by Adam Herman View Post
    i think you may be barking up the wrong tree... the sides of a spade bit do not cut the wood, only the spurs and the bottom edge do. I do not believe you will get your desired results with a spade bit with tapered sides. The sides will scrape and create a mass amount of friction and terrible hole quality if you have enough to power them scraping through the hole. how deep are the holes you need to drill?

    what you really want is a tapered reamer.
    A few years ago I made a special bit for drilling tapered socket holes to hold candles from a spade bit. I marked the bit to the angle I wanted and ground the edges of the spade so the leading edge of the tapered part as it rotated was an acute angle, making it a cutting edge. It worked just fine with no burning whatsoever.
    Lee Schierer
    USNA '71
    Go Navy!

    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! Please Contribute

  9. #24
    Join Date
    Jul 2015
    Location
    North Virginia
    Posts
    341
    Personally, I would drill the hole with the smaller diameter straight bit - then ream the hole using one of the tapered reamers from Lee Valley. That's what I do for staked legs on benches, chairs and whatnot. Relatively easy to do and creates perfectly-tapered holes. All three of these reamers are tapered at 12.8 degrees.

    http://www.leevalley.com/us/wood/pag...40,53317,54864
    http://www.leevalley.com/us/wood/pag...80,42240,53317

  10. #25
    This sounds like a perfect project to use a cnc... Just saying...

    C

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