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
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.
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...?
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.
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.
My choice of metals would be drill rod. Air or oil hardened. Easy to harden after you shape it.
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!
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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
This sounds like a perfect project to use a cnc... Just saying...
C