# Countersinks- Single flute/Zero Flute....?



## EmilioG (Apr 30, 2017)

I own and have used a variety of countersinks, most are Keo and Melin.  Single flute, multi flute, zero flute, cobalt, HSS, etc..in 82 and 90°, which is what I use most often. Size range from 1/8"-7/8".
Using slow speeds, I get the best results but sometimes I get some chatter which results in munged up countersink op.

What are you gentlemen using that gives the best results? in steel and non ferrous materials. I use mostly tool steel, mild steel (1018 1041), aluminum, bronze, copper and brass.  what works best with what? I try to countersink right after I drill a hole to keep things lined up.


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## 4GSR (Apr 30, 2017)

Single flute and the Weldon zero flute ones is what I prefer.  Multi-flute C'Sinks have the tendency to chatter regardless what you try to do to remedy the chatter. Generally have to run very slow to keep the chatter out.


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## David S (Apr 30, 2017)

May I ride on this thread and ask if anyone can identify this type of countersink?  I have searched all over and have no idea what they are called.





David


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## mikey (Apr 30, 2017)

I use Keo and Weldon zero flute countersinks exclusively to chamfer holes and countersink for screw heads. I prefer single flute countersinks from MA Ford to create accurate tapered sockets.


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## EmilioG (Apr 30, 2017)

Are the zero flute CS's easy to sharpen? How?


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## Rustrp (Apr 30, 2017)

EmilioG said:


> Are the zero flute CS's easy to sharpen? How?


Send them out to have them sharpened at about 1/3rd the cost of new.  The same with the single flute M A Ford, Severance CS tools.


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## Rustrp (Apr 30, 2017)

David S said:


> May I ride on this thread and ask if anyone can identify this type of countersink?  I have searched all over and have no idea what they are called.
> 
> View attachment 232548
> View attachment 232549
> ...


It's a single flute CS design for an insert.


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## EmilioG (Apr 30, 2017)

Why is Weldon CS so popular? Is it the range that they can CS?  I have not seen another CS brand that has this range.


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## Bob Korves (Apr 30, 2017)

Countersinks need to be fed at higher rates than many of us are willing to try.  The tool needs to be cutting real chips, not powder.  Slow speed + fairly heavy feed = success!  Slow feed = dull cutter...


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## 4GSR (Apr 30, 2017)

EmilioG said:


> Are the zero flute CS's easy to sharpen? How?


If you're a DIY like me, Weldon used to make a sharpening fixture that was an accessory for your T & C grinder.  I have one I picked up several years ago and have not used it to this day.  Like Rustrp said, "send them out for sharpening".

EDIT- The fixture has a one lobe cam that is used in the sharpening process.  And depending on the diameter of the countersink, you have different height lobes to choose from. There is a little hit and miss using this this of sharpening fixture, too.


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## JimDawson (Apr 30, 2017)

4gsr said:


> Single flute and the Weldon zero flute ones is what I prefer.  Multi-flute C'Sinks have the tendency to chatter regardless what you try to do to remedy the chatter. Generally have to run very slow to keep the chatter out.




+1.  All of my counter sinks are single or 0 flute.  Run them slow with cutting oil, and be aggressive with the feed.


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## EmilioG (Apr 30, 2017)

Who does one off CS sharpening for a reasonable price?  I've been looking for a good company, not only for countersinks but for
reamers. Is there someone that will sharpen 3 or 4 CS's?


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## Rustrp (Apr 30, 2017)

EmilioG said:


> What are you gentlemen using that gives the best results?



My experience; First I buy high quality because anything other than this in countersinking (other than soft wood) is throwing good money after after bad ending up with bad results. The zero flute's work well but I tend to restrict them to smaller diameters and non ferrous because they don't stay sharp as long as the single flute's. I have 2-3 M.A. Ford's (carbide) still in the package because I didn't want to get stuck halfway through the job with a dull CS.'s, and that was based on another CS brand.  This was a 304 stainless project and after 50+ 1/4" holes using Tapmatic EDGE creame, and still going strong I can't say anything but positive. As Bob already said; Slow speed and heavy feed.


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## Rustrp (Apr 30, 2017)

EmilioG said:


> Who does one off CS sharpening for a reasonable price?  I've been looking for a good company, not only for countersinks but for
> reamers. Is there someone that will sharpen 3 or 4 CS's?


I suggest asking your industrial machine tool supplier. Look for tool grinding services. Looking for sharpening services includes too many knife, lawnmower and saw blade sharpening services.

Edit; ....or a quick Google gets you Superior Tool Co. Inc. in Tanawanda, NY. 
There must be more services closer to you in Connecticut or Massachusetts.


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## woodchucker (Apr 30, 2017)

I prefer my weldon zero flute over others.  I have both unpiloted and piloted.
I have 4 flute, 1 flute, 3 flut, and if I remember a 6 flute.   still prefer the zero, in my opinion usually gives the nicest finish, least chatter, and most controllable depth free hand w/o a stop.


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## darkzero (Apr 30, 2017)

I also favor single flute & zero flute countersinks. They work the best for me.

I bought a box of countersinks & centerdrills from a local retired machinist. Most of the CSs are single flute, all US made. In the box were also some multiflute CSs, some with spiral flutes. I mainly use the single flutes on my lathe. The multiflutes also work well but I find I need to feed them much faster/harder than the single flutes to avoid chatter. Like the others I spin all my CSs slow.

In the box were also some of those threaded shank CSs with pilots that screw onto an extended shank. Not sure what they are called but they are used in the aircraft industry. The guy used to work at Lockheed or something like that. They're 2 or 3 flute & also work well but I only have them in smaller sizes. Great for reaching into a hole or a hole that is in a deep area.

On my mill I like using the zero flutes. On my mill, sometimes the single flutes won't countersink concentrically with the hole, they'll sometimes wander. I thought maybe the CS I used was dull or something but it happens randomly. I'm sure it's just my mill's quill. Multiflutes don't wander for me & neither do the zero flutes. Doesn't happen on my lathe though with single flutes and the multiflutes tend to chatter on my lathe.

I got a set of KEO cobalt zero flute CSs brand new in case for dirt cheap, I love them. From the same seller, later I also got a set of KEO 6 flutes. I haven't used them much but they were dirt cheap too so I hopped on the set.




EmilioG said:


> Why is Weldon CS so popular? Is it the range that they can CS?  I have not seen another CS brand that has this range.



When I was searching for zero flutes, it seems like the Weldons are most popular even though others make them now. They don't actually have Weldon shanks, it's the brand as you know. Maybe back then they were the first to make them?


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## EmilioG (Apr 30, 2017)

Will, are you using your CS's on steel or aluminum? Do the zero flutes work well on steel? Have you used them on tool steel?


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## darkzero (Apr 30, 2017)

I use my single flutes on alumn, brass, delrin, steel, SS, & titanium gr5 without issues.

My zero flutes I have only used on mild steel & non ferrous so far. I have not tried them on tool steel or Ti.


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## EmilioG (Apr 30, 2017)

I don't expect a zero flute to hold up well against steel in general. The thin edges just won't hold up.
I'll try my 3 flute HSS countersinks. I also have a new Melin Tin coated, cobalt CS that I'll test against tool steel.


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## mikey (Apr 30, 2017)

EmilioG said:


> Are the zero flute CS's easy to sharpen? How?



Yes, they are easy to sharpen. You just run a grinding stone (Dremel sells these) inside the hole, keeping the stone flat against the inside wall of the hole. The outside shape is untouched; you are bringing the cutting edge to sharpness on the inside or interior edge. I have zero flute countersinks that must be 20 years old and cut like new. I don't sharpen the outer cone; it requires a special grind and I haven't found it necessary to sharpen it this way.

The zero flute countersinks will cut steel, tool steel, stainless, aluminum and brass with no problems. Keep speed down around 100 rpm and feed to produce a continuous chip.

Single flute cutters produce a more precise shape, at least in my opinion. You buy them to suit the angle you need and these also need to be used at low speeds because you only have a single flute cutting. A positive feed and cutting oil produces a continuous chip to give you an accurate taper. Those from MA Ford seem to hold an edge better than others I've tried but they're expensive for what they are.


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## EmilioG (Apr 30, 2017)

Great information Mikey. I don't have any MA Ford cutters but may get a set if they come up for a good price.
I have several in 82 and 90° of various sizes for metric and imperial fasteners and to chamfer holes when needed.
A good amount of cutting oil is also key, I think.  I was running my CS's much too fast.


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## Rustrp (Apr 30, 2017)

mikey said:


> You just run a grinding stone (Dremel sells these) inside the hole, keeping the stone flat against the inside wall of the hole.


Thanks, I will give this a try. I haven't had a problem with them cutting and I like the results produced, it's how long they stay sharp on steel or stainless that's the issue.


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## Rustrp (Apr 30, 2017)

EmilioG said:


> I was running my CS's much too fast.


 Which will result in you thinking it's junk. :|


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## mikey (Apr 30, 2017)

EmilioG said:


> Great information Mikey. I don't have any MA Ford cutters but may get a set if they come up for a good price.
> I have several in 82 and 90° of various sizes for metric and imperial fasteners and to chamfer holes when needed.
> A good amount of cutting oil is also key, I think.  I was running my CS's much too fast.



Actually, if you look at the recommended cutting speeds for zero flute cutters, Weldon suggests speeds that are too high, especially for their smaller countersinks. For Aluminum, they recommend 1000 - 2000 rpm and for mild steel and cast iron, 200 - 1000 rpm. I find this too high for what amounts to a single flute cutting edge. At these speeds you get tiny chips, not a curled chip. I guess that's okay but I much prefer a lower speed and a positive feed to produce a continuous chip. The cutting edge lasts longer and I don't overheat my tool this way.


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## mikey (Apr 30, 2017)

Rustrp said:


> Thanks, I will give this a try. I haven't had a problem with them cutting and I like the results produced, it's how long they stay sharp on steel or stainless that's the issue.



Try to keep the grinding stone flat against the inside walls and go all the way around the cutting lip. This has worked well for me for a very long time. For steels, especially stainless steels, I think we agree that slow speeds work best and hopefully this will keep work hardening to a minimum. Let us know how things work out!

EDIT: I should be clearer about the grinding thing. You are using a cylindrical stone inside the tool and coming in from the back side, the opening opposite from the cutting edge. You keep the stone flat against the wall of the tool and grind the entire inside wall of the hole. This simply guides the stone so you don't roll the edge at the cutting interface. Use a light touch. It takes me less than 30 seconds to sharpen a zero flute cutter this way and it cuts like new. Hope this is clear.


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## EmilioG (Apr 30, 2017)

Would using the tapered round dremel stone work?


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## chips&more (Apr 30, 2017)

I also have the Cogsdill Micro-Limit precision depth control countersinking tool (pic). It’s not for everything you want to countersink. But when used, it does a real slick job of it. Easy to control depth, easy to have the countersink lined up & square, repeating the same countersink is a snap, chatter is hard to do and you can use a hand held drill motor to do it, And I’m sure there is more than one brand out there, Dave.


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## mikey (Apr 30, 2017)

EmilioG said:


> Would using the tapered round dremel stone work?



Dunno', never used a tapered one. I use the pinkish colored one, about 1/4" OD with straight sides.


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## Toysinthehood (Apr 30, 2017)

I prefer multiple flutes. Single flute: That's all we had in  school, and usually they had problems of their own already.  Chatter: Try slow rpm and increasing feed or somehow cutting a multi staged countersink.  You're basically ramming it in instead of sneaking up so the metal *probably* is more or less being formed depending on when it decided to break a chip. If you were boring a(n) internal taper would you start at the maximum depth of cut or work your way into the material.

Sent from my RCT6513W87 using Tapatalk


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## Bob Korves (Apr 30, 2017)

chips&more said:


> I also have the Cogsdill Micro-Limit precision depth control countersinking tool (pic). It’s not for everything you want to countersink. But when used, it does a real slick job of it. Easy to control depth, easy to have the countersink lined up & square, repeating the same countersink is a snap, chatter is hard to do and you can use a hand held drill motor to do it, And I’m sure there is more than one brand out there, Dave.
> View attachment 232565


Dave, in the aircraft industry where those are mostly used, they are called micrometer countersinks, and indeed you can make high precision countersinks with them, accurate and repeatable to .001" in depth.  The aircraft mechanics mostly use them for countersinking Alclad aluminum sheet for exposed flush countersunk rivet heads.  I have just one of them, and it is a treasured tool.  The aircraft guys also use angle air drills with a very short 1/4-20 socket and short threaded drills, countersinks, counterbores, etc. (like those at the left side of your photo) for working in the tight quarters of aircraft wings and other god awful places with poor access.  I am looking for one of those air drills for a reasonable price and with a reasonably slow speed.  I have lots of the 1/4" tools, and they are sold cheap on ePay, high quality, too.


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## chips&more (May 1, 2017)

Bob Korves said:


> Dave, in the aircraft industry where those are mostly used, they are called micrometer countersinks, and indeed you can make high precision countersinks with them, accurate and repeatable to .001" in depth.  The aircraft mechanics mostly use them for countersinking Alclad aluminum sheet for exposed flush countersunk rivet heads.  I have just one of them, and it is a treasured tool.  The aircraft guys also use angle air drills with a very short 1/4-20 socket and short threaded drills, countersinks, counterbores, etc. (like those at the left side of your photo) for working in the tight quarters of aircraft wings and other god awful places with poor access.  I am looking for one of those air drills for a reasonable price and with a reasonably slow speed.  I have lots of the 1/4" tools, and they are sold cheap on ePay, high quality, too.


No promise, but I’m pretty sure I have more than one of those pneumatic right angle drill motors. But I have not seen any of them in my piles in about the last 20 years. Please understand if I come across them, it will be a random good luck kinda find. I will let you know, don’t hold your breath. Also in my pic above, the lower right corner, that lonely part is also right angle drive for very tight places. You can see the 1/4” drive shaft. The other end has a threaded hole for those bits. In the body of the thing is the gear train…Dave


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## Bob Korves (May 1, 2017)

chips&more said:


> No promise, but I’m pretty sure I have more than one of those pneumatic right angle drill motors. But I have not seen any of them in my piles in about the last 20 years. Please understand if I come across them, it will be a random good luck kinda find. I will let you know, don’t hold your breath. Also in my pic above, the lower right corner, that lonely part is also right angle drive for very tight places. You can see the 1/4” drive shaft. The other end has a threaded hole for those bits. In the body of the thing is the gear train…Dave


I have not seen that style of right angle drive, Dave.  What are the two tools just above it in the pic?


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## EmilioG (May 1, 2017)

Rustrp said:


> I suggest asking your industrial machine tool supplier. Look for tool grinding services. Looking for sharpening services includes too many knife, lawnmower and saw blade sharpening services.
> 
> Edit; ....or a quick Google gets you Superior Tool Co. Inc. in Tanawanda, NY.
> There must be more services closer to you in Connecticut or Massachusetts.



I've looked into all of the sharpening services that I could find and not one is doing just a few tools.  They cater to large companies sending in dozens of cutters., not two or three I'm afraid.


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## mikey (May 1, 2017)

You might contact Weldon Tool Company and see if they will sharpen small quantities. I know Borite will sharpen individual boring bars for a small fee.


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## EmilioG (May 1, 2017)

I didn't know that about Borite.  I'm not to worried about it. I have many sharp CS's and the zero flutes can be sharpened with a dremel.
I have Borite cobalt bars which can also be hand sharpened., but good to know.  I just bought two, brand new Weldons for $15.00
Can the single flutes be touched up by stoning the flat single side? I won't touch the outside.


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## chips&more (May 1, 2017)

Bob Korves said:


> I have not seen that style of right angle drive, Dave.  What are the two tools just above it in the pic?


Those are reamers with the same threaded business end. I also have drill bits, more countersinks, end mills and toolaholic stuff of the like.


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## Bob Korves (May 1, 2017)

chips&more said:


> Those are reamers with the same threaded business end. I also have drill bits, more countersinks, end mills and toolaholic stuff of the like.


I have the drills, countersinks, counterbores, and I just looked and it turns out that I have two of the micrometer countersinks, one small and one large, and some of the reamers as well, they are shorter ones.  So far I have not had too much use for the stuff, but I can sure see them being useful when a difficult access job comes along.  Toolaholics, indeed...


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## mikey (May 1, 2017)

EmilioG said:


> I didn't know that about Borite.  I'm not to worried about it. I have many sharp CS's and the zero flutes can be sharpened with a dremel.
> I have Borite cobalt bars which can also be hand sharpened., but good to know.  I just bought two, brand new Weldons for $15.00
> Can the single flutes be touched up by stoning the flat single side? I won't touch the outside.



Borite will sharpen any of their boring bars. I think it was $6.50 per piece. Not something you would do for a cobalt bar unless you were really inexperienced or are so well heeled that you couldn't be bothered.

If the single flute cutter you have has a flat on the inner cutting edge then you can hone it sharp. If it is curved then you are better off not doing it. My MA Ford tools have a curve to them. The one I use most often has got to be more than 20 years old and is still sharp so I admit I haven't tried honing it.


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## EmilioG (May 1, 2017)

Yep, one flat, single flute. My Melin 6 flute is cobalt w/Tin coating. haven't tried it yet. Zero flutes are all cobalt, so they should stay sharp for a while.
I'll contact Borite. Thanks.  I'm going to test them with steel and non ferrous, one by one. Aluminum is easy, never had a problem. I've only gotten chatter with steel.
I'll slow down and feed fast.


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## ahazi (Jan 17, 2022)

I know it is an old thread but still relevant.

I found this sharpening method on YouTube, not perfect (for us machinists...) but a good idea on how to sharpen single flute countersinks.

1005. How To Sharpen Countersinks

Any other ideas and improvements are welcome.

*Edit:* I found a more precise demo that uses the same concept:
Sharpening a Single Flute Countersink with a Cuttermaster Professional 

I will try to make a jig that will use my 5C collets for this kind of sharpening

Ariel


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## Dan Krager (Jan 18, 2022)

Man, I must have awakened grumpy or maybe I'm just a grumpy old man.  

In the above videos I found that the first one "1005...." the operator didn't use a precise setup but he ground the proper cutting edge relief. In the second video, the operator precisely ground away all the relief, even changed the angle of the taper ever so slightly. From my experience in the machine shop of Jostens years ago sharpening their HSS pantograph cutters, once the taper angle has been carefully established from the cutting edge or a known standard, the sharpening passes start with removing the material that trails the cutting edge.  As the cutter material is rotated against the wheel, usually a cup wheel, the rotation stops as soon as the back of the cutting edge is reached. This is repeated until the cutting edge has been restored and with proper relief behind it.  

Is there some advantage to having no cutting relief behind the edge?  In my experience, whether it's a drill, mill, countersink or something else, a bit of draft is necessary.  Am I missing something?  
DanK


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## ericc (Jan 18, 2022)

Dan Krager said:


> Man, I must have awakened grumpy or maybe I'm just a grumpy old man.
> 
> In the above videos I found that the first one "1005...." the operator didn't use a precise setup but he ground the proper cutting edge relief. In the second video, the operator precisely ground away all the relief, even changed the angle of the taper ever so slightly. From my experience in the machine shop of Jostens years ago sharpening their HSS pantograph cutters, once the taper angle has been carefully established from the cutting edge or a known standard, the sharpening passes start with removing the material that trails the cutting edge.  As the cutter material is rotated against the wheel, usually a cup wheel, the rotation stops as soon as the back of the cutting edge is reached. This is repeated until the cutting edge has been restored and with proper relief behind it.
> 
> ...


I agree.  The main point of cutting edge relief was lost in both videos.  One of the comments called him out for this.  I wonder if you can get decent results by following the "thin blue line" method: blue the surface and grind like a twist drill, just leaving a thin blue line at the cutting edge.


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## Dan Krager (Jan 18, 2022)

Yes, that works, ericc.  How thin is a personal reaction to how long one wants the edge to last in the material being cut. 
DanK


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## paradox_pete (Jan 18, 2022)

I'm not expert, but Tom Lipton has a couple videos that I like better.

Monday Night Meatloaf 13

Monday Night Meatloaf 13 Leftovers


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