Sharpen drill bit on a drill press

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Len wrote:

Ditto.
I didn't get to the lathe bit part until I took an intro (Machine Trades 101) class at the local Community College. On the other hand, my nearest "hardware store" is a Production Tool ;-)
I've taught that drill sharpening technique to a lot of guys since - but always in person. I hope that the written instruction was sufficient for the OP (and others) to follow. It's just ridiculous to throw away a 3" long drill bit just because the first .005" of it is dull.
I would like to add three safety tips that apply anytime a grinder is to be used:
1) NEVER stand in line with a grinding wheel when turning it on. If it's ever going to shatter, this is the most likely time for it. 2) NEVER mount a wheel that doesn't ring like a bell when suspended from a nail and given a tap on the side with a small piece of metal. It should be presumed to be cracked and just waiting for you to turn the grinder on with it mounted. FINISH BREAKING IT to keep anyone else from trying to mount it. 3) Eye doctors can use tiny, but powerful, magnets to tease small chunks of metal out of your eye ... but grinding wheels aren't metal, are they? Wear GOOD eye protection when using a bench grinder or sanding belt. Wear goggles. Better yet, wear goggles under a face shield. Do NOT rely on temporary side shields. DO NOT rely on your prescription lenses. Blind is forever.
There are other safety rules for grinders (provide for lung protection, no grinding on the side of the wheel, keep the grinding platform within the thickness of a dime to the wheel, and so on) but these will do for a start.
Bill
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RayV wrote:

So buy some drill bits. They're not expensive, even for decent ones. If you're drilling something hard, then a set of real M42 cobalt bits is pricey but wonderful. NB - these are silver, not just a blue coating (those are worthless).

My experience: It was supposed to work except that they mis-moulded a chuck component making it useless. UK service backup was negligible -- maybe the US is better.

Great gadget, so long as you set the little nose piece up accurately and you're working with bits of 1/4" and over.
OTOH, I don't often break 1/4" and I don't even wear them out that fast. The ones I go through are 3mm - 5mm that I've snapped in half. Sharpening those is from hard to impossible (if there's no length left).
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work on one side at a time, obviously the same hand position on each. when done the geometry on one side is the same as the other. When looking at the very end you should see a straight line, the "peak" should divide the geometry exactly, meaning both sides are the same. It needs the angle measured co-axial from the peak through to the cutting edge, what 118 for std material, and also some backard clearance, what 9 degrees. In practice for most wood, if it looks good, and equal, alls well. The cutting lip should be sharp along its entire path while spinning. Often easier by hand. Machinery's Handbook tells you how to make the tooling after doing the calculations for actually making all the geometry correct for something so simple.
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start with the cutting lip, and sort of spin and up-shove if using a g-wheel. Its a minor movement. Google.. Actually I don't even know the right procedure. I use anything handy- like a ut-off wheel on a dremel. The geometry is gonna cut, or it ain't, precision ain't important for most. Its freakin incredidble the physics and math that make it what it is to be what it is though, cuting tools of any type.
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I guess the point is, you can't use the drill press b/c of the stationary stone, or whatever ,would need to cam in and out while following the flute while spinning to sharpen. If you look a the construction of bit stock, though, there is actually a land on the outer edge , so the outside perimeter has clearance too.
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RayV wrote:

Reading the DD manual helped out with understanding what it is doing. The bit needs to be aligned in the 'chuck' The chuck has a cammed ring that pivots the bit as you rotate it to create the relief angle. Pretty neat idea. http://www.genext.drilldoctor.com/PDF/350X%20Users%20Guide.pdf I can only assume the grinding jig does something similar.
I'm gonna try Bill's method and see if I can get the hang of it before I consider a DD.
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There is a old trick I always use.... when there is no gage available you can hold two HEX nuts side to side touching between your thumb and forefinger for the right angle.( hold up to light with drillbit to see.) airbrush
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Yes, you're missing something. Clearance.

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The Drill Doctor and the angle guide are almost certainly doing much more than you think. Twist drills are deceptively complex.

Nope. Take a look at the tip of a fresh drill bit- in particular, the fact that the tip is not pointy like a pencil.
You can sharpen them freehand on a belt sander or fine grinding wheel, but it takes a little practice, and it really helps to have someone show you how in person. I'll try to descibe it, but I don't know how much it will help.
Basically, there are two huge things to worry about- The first is the tip profile. It should look like a forward slash ( / ), and not a point. The middle of the slash should cross the center of the bit.
The second is the "wing" angle. It should be 135* on most bits.
To get the profile right, you need to start grinding near the cutting edge (be careful not to round it off), and rotate the bit until it has ground that entire side. You can do this several times, but you're not rotating the bit all the way around. Once you're happy with the first side, lift the bit off the wheel, and rotate it 180* degrees, and repeat the process until the tip profile is centered.
It takes a fair amount of practice, but it's not too tough once you get the hang of it.
The drill sharpeners have an indexer to get the bit in the right position, then lock it so that it is properly aligned with the cams. As you twist the holder, it rides on cams to raise the bit appropriately as it nears the back of the grind. Well worth the $$$ to get one if you've got a lot of bits to sharpen, IMO.
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The method you propose will not duplicate the geometry of a correctly sharpened drill bit. I'm not sure I can explain it verbally, but here goes: the surface that trails the cutting edge must be angled so that iit provides a clearance angle for the cutting edge. If the bit was sharpened by merely spinning it against a fixed abrasive surface, there would be 0 deg clearance angle. Using such a bit would be equivalent to trying to lift a shaving with a chisel while keeping the flat back flat against the wood. IOW, without the clearance angle, the cutting edge cannot actually contact the work.
The good news is, in larger drill sizes, it is not too difficult to sharpen a drill bit to effectively cut wood using an ordinary bench grinder. With more practice, you can do a passable job at sharpening a bit to effectively cut metal as well. There are some good books out there that will explain how, or perhaps you know someone who already knows how. I was lucky enough to have an old machinist show me how over 30 years ago. That guy would actually take a drill bit to the grinder and custom grind it for the type of surface he was using it on. BTW, if you are only drilling wood with a twist bit, you can steepen the effective cutting angle quite a bit (no pun intended) than the general purpose metal twist bits and they will work a lot faster & cooler.
Smaller sizes are tougher to regrind by hand, depending on skill, eyesight, steadyness of hand, etc. For me, anything smaller than 1/4" or maybe 3/16 is a throwaway.
--
Make it as simple as possible, but no simpler.

Larry Wasserman - Baltimore Maryland - snipped-for-privacy@charm.net
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<snip>

skill,
than 1/4"

Larry,
Those various sized/shaped ceramic sticks available from Garrett-Wade, etc., work quite well for hand sharpening smaller sized drill bits.
Hold the bit upright in a vice and run a 600/800 grit flat ceramic stick from the back of the flute towards the cutting lip.
Use the same pressure and number of strokes on both sides.
Repeat with finer grit ceramic sticks until you've got a good edge.
Use a 1200 grit oval shaped ceramic stick to knock the burr off the cutting lips. The oval shape allows it to fit into the flute of small drill bits with less chance of creating a groove than the edge of a half-round ceramic stick (learned the hard way).
I've been able use the ceramic sticks on drill bits down to about #60.
Len
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