Spade drill bits vibrate strongly while drilling in wood

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Forum topic by simplex1 posted 07-12-2020 07:52 PM 541 views 0 times favorited 12 replies Add to Favorites Watch
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3 posts in 22 days

07-12-2020 07:52 PM

Topic tags/keywords: asymmetric spade drill bits for wood

I bought recently a set of drill/drive bits and a RYOBI corded drill/drive (see the pictures below). I did some tests with a few drill and drive bits and they work satisfactorily except the spade ones that vibrate strongly while drilling holes in wood. The spade bit was always properly mounted in the chuck. The problem is that the part of the bit that cuts into the wood is not symmetric (see the first picture below). I can see this by spinning the bit, while not drilling, and looking at its head. The asymmetry is small and can not be seen unless the drill rotates.

The question is: Are these vibrations and the asymmetry of the spade drill bits normal or I bought some low quality bits?

Spade drill bit not centered

Mastercraft 104 Pieces Drill and Driving Kit

RYOBI 3/8-inch Variable Speed Clutch Driver

12 replies so far

View John Smith's profile

John Smith

2501 posts in 962 days

#1 posted 07-12-2020 09:19 PM

buy a small set of quality bits and you will see (and feel) the difference.


-- there is no educational alternative to having a front row seat in the School of Hard Knocks. --

View OnhillWW's profile


246 posts in 2031 days

#2 posted 07-12-2020 09:28 PM

What John said. See my signature below.

-- Cheap is expensive! - my Dad

View ibewjon's profile


1731 posts in 3592 days

#3 posted 07-12-2020 09:32 PM

You got what you paid for. Although a spade bit is a crude tool, you apparently got the scrap.

View bandit571's profile


26092 posts in 3483 days

#4 posted 07-12-2020 09:35 PM

Regrind the tip to center the point….

-- A Planer? I'M the planer, this is what I use

View SMP's profile


2233 posts in 705 days

#5 posted 07-12-2020 10:17 PM

I once got a Christmas present stocking stuffer that was one of those sets from Costco, like 100 drill bits and drivers for $5 or whatever. The spade bits were so bad I almost broke my wrist using it in a corded drill. I ended up buying some Irwin spade bits at the big box store and though Irwin isn’t the greatest quality, they were night and day from those el cheapos.

View simplex1's profile


3 posts in 22 days

#6 posted 07-13-2020 09:40 AM

Thank you for your answers. I will buy a set of more expensive and, I hope, better spade drill bits but first I want to be sure that for the good bits the tip of the spade is not seen in two (very close to each other) locations while the bit is spinning idle. I am not 100% sure that this small asymmetry of the bit is really the cause of the vibrations.

For example, are these spade bit sets better?:

Bosch 6 pc. Daredevil Standard Spade Bit Set

Diablo 6 Piece Spade Bit Set with 2 Bonus Bits

They appear to work on a slightly different principle because they have a conical screw as their tip, unlike the ones I bought.

View Lazyman's profile (online now)


5624 posts in 2187 days

#7 posted 07-13-2020 11:31 AM

I can really recommend that Bosch set. They work great. Just be careful because the lead screw can really pull it in aggressively and if you are not prepared, it can torque your wrist.

-- Nathan, TX -- Hire the lazy man. He may not do as much work but that's because he will find a better way.

View Madmark2's profile


1450 posts in 1387 days

#8 posted 07-13-2020 01:31 PM

Don’t buy spade bits at all. Use Forstners or auger bits.

Spade bits are specifically cheap. End of story.

Caveat Emptor!

-- The hump with the stump and the pump!

View splintergroup's profile


3848 posts in 2022 days

#9 posted 07-13-2020 03:42 PM

I’m in the Madmark camp here. For my uses, spade bits are “sacrificial”, to be used when putting rough holes in tubafors for wiring or other “I just want a hole” chores.

Auger style bits are the cats meow compared to spade bits when used for a similar purpose. The screw tip makes them a no-no for drill press use, but can be handy for hand drill use. To make them the equivalent of spade bit functionality just grind down the screw threads. I’ve found even the cheap Harbor Freight augers to work well.

View theart's profile


201 posts in 1354 days

#10 posted 07-13-2020 04:47 PM

Don t buy spade bits at all. Use Forstners or auger bits.

Spade bits are specifically cheap. End of story.

Caveat Emptor!

- Madmark2

Expecting a clean hole, with minimal vibration, from a spade bit is like trying to get a clean cut with a Sawzall. Both are made for rough work where the odds of hitting hardware are high. They are not delicate instruments.

View Woodknack's profile


13428 posts in 3179 days

#11 posted 07-14-2020 12:20 AM

The only spade bits I’ve used that weren’t junk were Irwin. Everything else either wobbles or cuts rough.

-- Rick M,

View Robert's profile


3781 posts in 2280 days

#12 posted 07-14-2020 12:27 AM

Try a set of Irwin’s or Bosch you’ll be happy.

-- Everything is a prototype thats why its one of a kind!!

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