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Forstner Bit WithOUT Pilot or Spur Center

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39K views 36 replies 22 participants last post by  stewslaser  
#1 · (Edited by Moderator)
Does anyone know if someone makes a Forstner bit that does NOT have a pilot or spur center?

I'd like to drill a clean, flat-bottom hole without that divot in the center where the pilot point was.

~Aaron
 
#5 ·
I don't think that I would want to use a Forsner bit (or spade bit, hole saw, etc) without a center spur. That's what keeps the thing from trying to skate all over the place when it's turning.

Just for giggles, try using a hole saw without the drill bit.
 
#10 ·
Use two bits the same size, one WITH the spur, one WITHOUT. Start your hole with the spur-bit to get the outer portion of the bit below the surface and then switch to the de-spurred bit to finish. You did not say how deep your intended hole is so this may or may not work for you.
 
#14 ·
I've a small set of forstner bits that I simply grinded the bit off. You don't have to pre-drill it-just use a drill press and make sure your work item is clamped or otherwise secured down and it'll be fine. Go slow for the first couple of rotations to make a groove, then crank it up fast and hold on tight.

those flat-on-purpose bits look really cool!
 
#15 ·
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#16 ·
I bet the rim-guided are not best sellers at $45 a pop.

How about start ALL the holes, then grind the spur to finish (and still need only one) ?

OP says "a… hole…" so maybe he only needs to do one, anyway.
 
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#17 ·
Historically, all Forstner Bits were "rim-guided." They had several advantages including flat-bottom holes, VERY accurate hole diameters, and are capable of drilling "partial" diameter holes since they are guided by the edge of the bit. In the last 20 years or so, machine spur "forstner" bits and other variations of bits got confused with the more traditional design. Techichally, only rim-guided" Forstner bits are truly Forstner Bits. Thank you Woodnerd for including the link to Jamestown Distributors that shows true Forstners.
 
#19 ·
What ever it is, it has to be strong!! Those feed screw pints take a lot of torque. years ago I need to drill a 2" hole through about 8" of framing for a conduit. The purchasing agent bought the cheapest forstner bit he could find without a feed screw. By the time I got that hole drilled, it was the most expensive 2" hole in the world!! Gotta love the stupid decisions people who have never done any real work do to save a buck ;-))
 
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#20 ·
Topamax… your's is good example of a good tool used for the wrong job. The correct bit would have been a bit such as is sold for plumbers or electricians, many times made by Milwaukee. The Forstner bit without the feed screw was not proper bit for this job,as you quickly discovered.
 
#26 ·
I went a different way when I needed big holes part way through the stock with no center mark. I cut the size hole I needed in a piece of scrap with a holesaw, taped it to my workpiece, and used a pattern bit in my router. Made a very clean job of it!
 
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