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Walter Mooney
02-21-2017, 7:42 PM
Hello All,

I need to drill a series of tapered holes through some 3/4" (19mm) pine , and I think a tapered spade bit would work perfectly after I grind a taper on each side. The larger diameter will be 1-3/4" (45 mm) and the small diameter will be 1-3/8" (35 mm). I could grind the taper, then grind the angled side with a bevel of sorts yielding a cutting edge. Anyone know where I can find/buy a spade but that's 1-3/4" - 2" wide? Anyone ever seen such a bit?

Thanks in advance for your help.

P. S. I'm usually over in the "All things spinny" area looking and admiring.

Walter

Mark Katz
02-22-2017, 10:16 AM
Methinks you would be better off (and safer) using a router for this. For your situation, the slope of the sides is 5mm/19mm = .263 which is 15.25 degrees. Rockler and others sell a 15 degree chamfering bit (e.g. http://www.rockler.com/15-chamfer-router-bit). It has a bottom bearing.

Start by making a template with a clean 35 mm hole (Use a 35 mm Forstner bit, for example). Then, use a 1.25 inch Forstner bit to cut a starter hole in your piece. Clamp your piece above your template with the holes centered and use the router bit above to enlarge the starter hole resulting in your tapered hole.