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Dull Drill Bits

Posted By: BigJohn

Dull Drill Bits - 12/29/05 01:02 AM

I end up using paddle bits a lot during rough-ins when an auger-drill isn't available or would just be too inconvenient to use. All the use dulls bits in a heartbeat and a new paddle-bit might only last me about five days.

Can these things be sharpened effectively?

I've been looking into using different types of bits, ones that have a circular blade seem like they might work better: more cutting area = longer life? But a lot of these bits seem designed for precision wood work, not use and abuse with framing lumber.

Am I stuck constantly shelling out for new paddle bits or does anyone know an alternative?

-John
Posted By: BobH

Re: Dull Drill Bits - 12/29/05 01:32 AM

Big John, hit em with a grinding wheel. I've been using the same cheapo bits forever and this is what I do. Either that, if you have time, a file.
Posted By: Trumpy

Re: Dull Drill Bits - 12/29/05 01:44 AM

You can also ruin a perfectly good drill bit by sharpening the wrong part of it or by sharpening it at the wrong angle. [Linked Image]
Posted By: BigB

Re: Dull Drill Bits - 12/29/05 02:12 AM

Bosch makes paddle bits with screw tips. I bought some and so far they have held up really good, plus they really plow thru the wood fast. By the way, a forstner bit works well in those tight spaces.
Posted By: gfretwell

Re: Dull Drill Bits - 12/29/05 02:40 AM

I agree with Bob. I have found rusty spade bits in the yard and brought them back from the dead.
You do need a bench grinder with an adjustable guide, at least I do but I can get them very close to the factory angle.
I have had a lot worse luck with twist drills and the assortment of sharpening tools I have accumulated over the years.
Posted By: u2slow

Re: Dull Drill Bits - 12/29/05 03:50 AM

Tried the Milwaukee self-feed bits? I've only tried one briefly, but it worked well.

[Linked Image]
Posted By: BobH

Re: Dull Drill Bits - 12/29/05 04:37 PM

I've never ruined a bit to the extent that I can't fix it. It's just a paddle bit, so what if you get the wrong angle, they'll still cut like new. I do the same with my regular drill bits, just takes a little practice. Better than buying bits every week like he's doing now.
Posted By: kdal

Re: Dull Drill Bits - 12/29/05 05:51 PM

I sharpen my augers and paddle bits with a dremel.Works great with a little practice. It also helps to have a new or good bit to go by.
Posted By: Spark Master Flash

Re: Dull Drill Bits - 12/29/05 06:55 PM

Hey Big John,

The flat face of the paddle bit meets the beveled end to form a sharp cutting edge. After a number of cuts, that edge gets beat up. Since this is a quick and easy thing to sharpen, I won't go into a lengthy diatribe about how to sharpen plane irons, chisels and scissors.

Here are a few tips.

- Maintain the factory bevel angle as you re-grind the bevel on the end.

- Don't grind the scoring burr off the end of the cutting edge, if you have such a burr.

- Grind the bevel until the flat face and bevel angle meet again all the way across.

- Don't overheat the metal. It can get too hot, especially right at the very cutting edge where the steel is thin. Quench it in some water here and there so it doesn't heat up. You can remove the temper of the steel by overheating, which will leave you with a claylike drill bit that will last about as long as a drill bit made of Silly Putty.

- There should only be two angles to make your cutting edge: the face and the bevel. Don't try to put another little bevel on the face side of the cutting edge. That will ruin the cutting action.

- Since paddle type bits have a sharp point in the center and sometimes scoring burrs at the perimeter, it is a good idea to do that kind of job with a Dremel.

- Don't leave the bit with an overhanging burr on the edge. You can use a fine diamond stone to flatten the face of the paddle bit and take off that burr. Go back & forth, face and bevel, until the burr is gone.

Remember, don't re-grind new angles on the bit. As you study the bit and all of its angles, you'll see where the cutting edge is located. The cutting edge might twist and turn slightly around the point and burrs, so when you sharpen the points keep the factory bevel intact.

One more little concept to ponder. To get the sharpest edge possible, first flatten the face of the bit with a diamond stone and work your way up through the grits until it's flat and smooth. Then work it over for a while with red jeweler's rouge until it's like a mirror.

Now that the face is flat, grind the bevel, work up through the grits and polish to a mirror finish.

Now you don't need a drill. You can hand-turn your mirror-finish drill bit through 6 inches of bird's-eye maple.

I'm happy that I can now sharpen everything I own, including Xacto knives (most people don't know how to sharpen things that are already that sharp), razor blades, drill bits, planes, chisels, scissors, axes, serrated blades, screwdriver tips, hammer claws, table saw blades, circular saw blades, hand saws, band saws, etc.! NOW DEN!

I taught a female artist friend how to sharpen a chisel, I flattened both faces on an old set of scissors she bought at a garage sale to return them to like-new shearing action, but she keeps trying to get me to sharpen all her stuff. Be wary of trying to teach a woman how to sharpen things - they don't want to know how to do it. Don't let anybody know you know how to sharpen anything. If you meet the wrong person, you'll be strapped to the sharpenin' post from now 'til the cows come home.
Posted By: e57

Re: Dull Drill Bits - 12/29/05 07:36 PM

Those milwaukee self feed bits a service can be provided to swap out sharp ones. I've known a few shops, especialy plumbers who get a service to resharpen them.
Posted By: BigJohn

Re: Dull Drill Bits - 12/30/05 12:35 AM

Sounds like the thing to do is break out the Dremel and just keep sharpening the same bit until there ain't nothing left to sharpen.

Should save me a few pennies. I appreciate all the help. And thanks Spark Master Flash for the details on sharpening.

-John
Posted By: briselec

Re: Dull Drill Bits - 12/30/05 01:24 PM

I use bullseye auger bits, cut the bullseye off and stick it in my armbreaker drill. They last a lot longer before needing sharpening.
Posted By: electricman2

Re: Dull Drill Bits - 12/30/05 03:03 PM

I use the cheap spade bits. Use a good file and you can keep them cutting for a long time. I don't want to spend big bucks for a auger bit and ruin it on the first hole. [Linked Image]
Posted By: macmikeman

Re: Dull Drill Bits - 12/30/05 03:56 PM

On the other hand you can just keep buying spade bits, wear em out fast, buy more, and deduct the cost of them from your tax return
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