I bought some countersink bits from a forum member here a while back that I really liked, they were 4 or 5 flute carbide. But when we used them in a hand drill, they chipped and didn't work very well. I had a zero flute countersink bit that worked pretty well, but when I bought another one it was absolute garbage. Might be a brand issue? We are countersinking 1/4" to 3/8" holes for flat head cap screws. Nothing critical, all for decoration purposes only. Anyone have some recommendations on good countersinking bits that work well in a cordless drill?
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Recommended countersink bit for hand drill use
- Thread starter Econdron
- Start date
- Replies 7
- Views 7,204
Chamfered umpty million holes with MA ford single flutes in a cordless. They are cheap, easy to touch up on the belt sander and work great.
Carbide countersinks don't fly well in hand held tools or even a drill press. They want higher rpm and lower feed. HSS ones want low speed, heavy feed.
Carbide countersinks don't fly well in hand held tools or even a drill press. They want higher rpm and lower feed. HSS ones want low speed, heavy feed.
EPAIII
Diamond
- Joined
- Nov 23, 2003
- Location
- Beaumont, TX, USA
IMHO, the only countersink to buy and use anywhere is the O flute countersink. The biggest advantage of this style is that chatter is almost impossible.
And YES, some brands are pure garbage. It is hard to get the necessary clearance right. Half of the hole needs to be high to form the cutting edge and the other half of the hole needs to be at the low end of the helix that forms the clearance behind the edge. The cheap ones do not get sharpened correctly and do not work right. Get a name brand. I started with a name brand set of five sizes and then purchased replacements that are also name brand.
A properly sharpened O flute countersink will easily cut a proper, smooth countersink in almost any material. At least any material that I have ever tried. And they work in a rigid mill/drill, in a drill press, in a hand held power drill, and even in a hand held hand powered drill. They just plain work.
Some feel that they are hard to sharpen. I have sharpened them with repeatable success. There are two methods: the easy one is to use a round stone (cylindrical) in a Dremel type tool. Run the Dremel on a somewhat slow speed and insert the stone in the hole in the countersink. Keep it parallel to the hole's axis and work on the cutting edge. This method only allows you to resharpen it a few times before the geometry is distorted: the cutting edge becomes too weak to hold up.
A better, but more difficult method is to take down the entire "cone" by a roughly equal amount. I like to use a slow wheel for this instead of the typical, high speed bench grinder. I have a Craftsman unit that has a built in water bath to keep the wheel wet. I start on the low end of the cone's helix with the tangential point on the stone about half way across the hole in the countersink. Then I rotate the CS backwards until the stone contacts the CS at the high end of the cone's helix. I try to keep the rotational speed of the CS and the pressure constant throughout this motion in order to keep the amount removed constant across the entire cone. This is repeated as needed. This can be done on either the round edge or the flat face of the abrasive wheel: I usually do it on the edge. The edge would be dressed flat/straight for this. If this is done hand held, mounting the CS in a loose drill chuck is a good idea.
With care, a bad O flute countersink could be improved by this second sharpening procedure, but many of them are not properly hardened so the effort is not necessarily rewarded.
And YES, some brands are pure garbage. It is hard to get the necessary clearance right. Half of the hole needs to be high to form the cutting edge and the other half of the hole needs to be at the low end of the helix that forms the clearance behind the edge. The cheap ones do not get sharpened correctly and do not work right. Get a name brand. I started with a name brand set of five sizes and then purchased replacements that are also name brand.
A properly sharpened O flute countersink will easily cut a proper, smooth countersink in almost any material. At least any material that I have ever tried. And they work in a rigid mill/drill, in a drill press, in a hand held power drill, and even in a hand held hand powered drill. They just plain work.
Some feel that they are hard to sharpen. I have sharpened them with repeatable success. There are two methods: the easy one is to use a round stone (cylindrical) in a Dremel type tool. Run the Dremel on a somewhat slow speed and insert the stone in the hole in the countersink. Keep it parallel to the hole's axis and work on the cutting edge. This method only allows you to resharpen it a few times before the geometry is distorted: the cutting edge becomes too weak to hold up.
A better, but more difficult method is to take down the entire "cone" by a roughly equal amount. I like to use a slow wheel for this instead of the typical, high speed bench grinder. I have a Craftsman unit that has a built in water bath to keep the wheel wet. I start on the low end of the cone's helix with the tangential point on the stone about half way across the hole in the countersink. Then I rotate the CS backwards until the stone contacts the CS at the high end of the cone's helix. I try to keep the rotational speed of the CS and the pressure constant throughout this motion in order to keep the amount removed constant across the entire cone. This is repeated as needed. This can be done on either the round edge or the flat face of the abrasive wheel: I usually do it on the edge. The edge would be dressed flat/straight for this. If this is done hand held, mounting the CS in a loose drill chuck is a good idea.
With care, a bad O flute countersink could be improved by this second sharpening procedure, but many of them are not properly hardened so the effort is not necessarily rewarded.
Job Shopper TN
Cast Iron
- Joined
- May 17, 2015
- Location
- Southeast TN
We use 6-flute MA Ford countersinks, they do pretty good. Don't seem to last real long before they start to dull, though. Admittedly, our guys are rough on 'em. Only issue with a six-flute (or 3-flute I believe) is you typically are limited as far as minimum hole size if you buy a bigger diameter. A good brand (Keo or MA Ford) single-flute countersink would be the most versatile.
Forestgnome
Stainless
- Joined
- Aug 2, 2008
- Location
- Californeeeah
The problem with a single flute or 0 flute in a hand drill is offsetting of the countersink from the hole, if concentricity is important. Multiple flute countersinks tend to stay on center. Just stay with HSS like stated. That said the 0 flute is my favorite in the drill press.
Bobw
Diamond
- Joined
- Feb 8, 2005
- Location
- Hatch, NM Chile capital of the WORLD
I've had a set of 4 (little to big) MA Ford zero flute countersinks for about 9 years now.
I mostly use them in a cordless for deburring, when they get dull I touch them up with a dremel stone
like described above...
Amazing tools, they have NO flutes, ZERO of them, and they look stupid.. They should never work, and for
years I wouldn't even try one... I'm glad I finally did.
Also as stated above, they tend to suck at maintaining concentrically to the hole when used by hand, or
even in a drill press when the CS isn't already perfectly aligned and rigid. They have no support on the
other side.
Flat head cap screw, as in big giant countersink??? So the bolt is flush?
A Counter Sink for a CS head bolt.. That's a big F'n countersink. That's a lot of contact area and not a
whole lot of support, especially in a hand drill. I'd buy quality brand name stuff(multi flute), maybe several different
types to see what works best, and then SLOW speed and feed the hell out of it. I wouldn't go carbide either.. I have a LOT
of those that are all nicely chipped.
Nothing looks worse than a 5 lobed countersink around the edges of a CS head bolt (or rivet).
I mostly use them in a cordless for deburring, when they get dull I touch them up with a dremel stone
like described above...
Amazing tools, they have NO flutes, ZERO of them, and they look stupid.. They should never work, and for
years I wouldn't even try one... I'm glad I finally did.
Also as stated above, they tend to suck at maintaining concentrically to the hole when used by hand, or
even in a drill press when the CS isn't already perfectly aligned and rigid. They have no support on the
other side.
Flat head cap screw, as in big giant countersink??? So the bolt is flush?
A Counter Sink for a CS head bolt.. That's a big F'n countersink. That's a lot of contact area and not a
whole lot of support, especially in a hand drill. I'd buy quality brand name stuff(multi flute), maybe several different
types to see what works best, and then SLOW speed and feed the hell out of it. I wouldn't go carbide either.. I have a LOT
of those that are all nicely chipped.
Nothing looks worse than a 5 lobed countersink around the edges of a CS head bolt (or rivet).
Rudd
Stainless
- Joined
- Jul 30, 2003
- Location
- savannah, jaw-ja
I've countersunk for a few bazillion rivets with a hand drill and one of these set-ups. Absolutely repeatable. Make sure you have the correct size pilot on the C'sink, I've found them with separate pilots that are held in by a leetle bitty setscrew.
Or make a smaller hole, c'sink to size, then open the hole up to full size.
9 Piece Countersink Cage & Cutter Kit | Brown Aviation & Aircraft Tools
That set will do your 1/4", I've seen the next size up that will do your 3/8".
Or make a smaller hole, c'sink to size, then open the hole up to full size.
9 Piece Countersink Cage & Cutter Kit | Brown Aviation & Aircraft Tools
That set will do your 1/4", I've seen the next size up that will do your 3/8".
projectnut
Stainless
- Joined
- Mar 4, 2006
- Location
- Wisconsin
For hand drill work I would recommend the MA Ford Uniflute countersinks. I bought an 82* set this back in 1986 and still use them today.
M.A. Ford - Product Lines
We did a lot of work using flat head screws. I couldn't tell you how many countersinks I've made with them, but it's many thousands at a minimum.
If concentricity is critical I would use something like the Brown kit mentioned. I also have several Magnavon cage and cutter kits. You can dial in a depth setting and have consistent results for 10 or 1000 holes. I'm not sure if Magnavon still makes the micro stop cages, but if your on a budget there are plenty of used ones available on e bay.
M.A. Ford - Product Lines
We did a lot of work using flat head screws. I couldn't tell you how many countersinks I've made with them, but it's many thousands at a minimum.
If concentricity is critical I would use something like the Brown kit mentioned. I also have several Magnavon cage and cutter kits. You can dial in a depth setting and have consistent results for 10 or 1000 holes. I'm not sure if Magnavon still makes the micro stop cages, but if your on a budget there are plenty of used ones available on e bay.
