View Full Version : i need a countersink, what type?

11-02-2009, 10:16 PM
i have a set of those countersinks that look like a cone with a hole in them. they work okay but me being an idiot i dulled the one i need yesterday. i have no idea how to resharpen it, and honestly, they don't work all that well (i only paid about $15 for the set of five).

so i need something new. i looked at the Enco site and there are a variety of countersinks. there are single-flute HSS, six-flute carbide, and a nifty one that takes carbide inserts (for a correspondingly nifty price, but made in the USA). i have no problem paying the price for the one with the inserts if it is actually better. i do a fair bit of countersinking and i am at times a little heavy-handed. will the one with the inserts hold up? also, can i use it in a good drill press, or must it be used in a milling machine? these will be used in pretty much any material you can think of (steel, aluminum, brass, plastic, maybe even wood).


andy b.

PS-so, how DO you sharpen one of those cone-shaped countersinks?

11-02-2009, 10:25 PM
Good post Andy, I'm interested in this as well.
I believe you mean Chamfer though.
EDIT, Maybe not :D

That aside, I have used the 6 flute HSS, do not like them at all, they always seem to chatter, could be I'm not using it properly.
The single flute I like. Learned long ago, just say no to the cheap stuff. Never tried a carbide 6 flute or the single hole type but read good things about the single hole, that is, the quality ones.


11-02-2009, 10:50 PM

i originally thought it was a chamfer as well, but every place has them listed as countersinks. :)

i like the idea of the one with the inserts because when i smash it i can just switch to a clean edge. but if they are fragile and break all the time, i may opt for something else.

andy b.

11-02-2009, 10:54 PM

i like the idea of the one with the inserts because when i smash it i can just switch to a clean edge. but if they are fragile and break all the time, i may opt for something else.

andy b.

I do to, why don't you buy one and let us know how it works and save us all the gloom and despair from wasted money :D

11-02-2009, 10:55 PM
I'm thinking you use a countersink to chamfer a hole. Some people call countersinks chamfers.


11-02-2009, 10:56 PM
First the zero flutes are easy to resharpen, get yourself a dremel with a little cylindrical stone on it and go in and follow the thru hole on the cutting side. It doesn't need to look nice, the outside of the "cone" is your form. Look for the edge that is actually doing the cutting and you'll see what you have to do.

Second, how are you using them? For a drill press or a cordless drill and deburring, the zero flutes you have work great. A 3,4 or 6 flute, when not in a rigid setup can chatter like a bastard. In the machines, I generally like a cheapie multi flute, by hand or drill press, the zero flute makes life very nice.

As to the quality of your set, this is a 2 man job shop and we play a lot after hours(make useless crap) and a $70 set of the MA fords has lasted almost 2.5 years, with only a few re-sharpenings, mostly in cordless drills for deburring, occasionally in the machines.

If you're looking to make big ass countersinks for countersunk head screws, look for something helical, or single flute, though the zero's work good there too. You won't break any speed records, but you also shouldn't run into some nasty chatter problems that you can get with a straight multi flute countersink, (quick way to trash out a carbide countersink, guess how I know).

I highly doubt you need an inserted one, those are made to make time.

One other thing, if you are trying to line up a hole on a drill press with a zero or single flute, its tough, the outer cone is helical, and if you push down to center, then clamp, you end up off center.

Paul Alciatore
11-03-2009, 03:52 AM
Re: zero flute countersinks.

First, Bob told you how to sharpen them.

Second, they are the best design and will produce the best surface with no clatter, but the cheap ones may not work well. They have a conical surface that is slightly relieved to allow them to cut. It goes inward for about 3/4 of the diameter and then jumps back out. This jump back needs to be in the leading half of the hole. The cutting edge, the back half of the hole should be at the highest diameter, but I have seen cheap ones where the hole is in the wrong place in relation to this relieved cone and they don't cut well. Some can be improved by sharpening but you may have to sharpen back quite a bit.

The good brands work well and they really are the best countersinks out there.

My second choice would be a one flute design.

11-03-2009, 04:56 AM
I can't comment on the single flute cutters, but the six flute HSS work fine if... you run them slow (low rpm), and clear the chips, they will pack quickly. We constantly use them for sinking 10-32 screws in die bases. Oh, and as always, quality cutters >> cheap stuff. MA Ford is nice stuff

11-03-2009, 07:22 AM
the single-flute ones at Enco are MA Ford, so that sounds like a good choice. they are offered in 60, 82, 90, 100 and 120 degree tapers. is one taper a better choice for general use? i use them for deburring, so in that case i guess it doesn't matter all that much, but i also use them to countersink holes for machine screws and such. i have no idea what a standard machine screw taper is.

andy b.

11-03-2009, 09:56 AM
What are the standard degree of c/s? I know in A/C sheetmetal a 100 degree is used and there are others.

Are there different angles in imperial and metric?

Are they varied like drill bits? Can't remember the angles off hand right now

11-03-2009, 10:14 AM
82 degrees for american
90 degrees for metric

11-03-2009, 09:39 PM
well i'm anti-metric, so it looks like 82 it is!

andy b.

11-03-2009, 09:57 PM
Another vote for the MA Ford single flute countersinks. Simply awesome. No chatter ever.


11-03-2009, 10:45 PM
Inserts are good for CNC or Mill work only, they will not take the abuse and chatter of a drill press setup without killing carbide inserts.

For me, it depends on the application. Single flute for drill press work, multi for mill.

John Stevenson
11-04-2009, 04:30 AM
Snowmans reply is very valid as the insert ones have the insert standing proud and there is no support for the rest of the body.
They are designed for fixed spindle / clamped work, fine with a Bridgy and vise but useless in a drill press.

Some while ago I had literally 1,000 of countersinks to do as an ongoing subcon job, some up to 30mm diameter.

I went thru J&L book and bought one of each type I though would work best, probably spent $200 to $300.
Single flute. the ones with holes in, multi flute, tipped, TiN coated, solid carbide in single and multi flute, the whole dogs dinner, some were $50 a pop :eek: but I reckoned if i could save time I'd save money.

At the end of the day the $14 M.A. Ford single flute TiN coated out cut and out lasted all the others, in fact still using some of them to this day.


11-04-2009, 05:18 AM
I use multiflute countersinks, 4 flute and 6 flute. I have never had good results from the "zero" flute or single flute types. I use a LOT of flush head cap screws for assembling my designs both steel and aluminum. For those I use six flute countersinks of the correct size for the head in question. To seat a flush head cap screw properly the hole is countersunk until the tool produces a straight edged hole of perhaps .020" depth at the top. This brings the head of the screw flush to the surface. The other types of countersinks don't do this well or at all in my experience.

The main secret to clean edges with no chatter is to clamp the work and to use a machine that doesn't have a lot of play in the spindle (cheap drill press= chatter). Low rpm and good pressure are also important. When countersinking use a cutting oil. It makes a big difference.

11-04-2009, 03:48 PM
I prefer the single flute type First then the one with the hole. Multi flute counter sinks are just a get buy want last long.

11-04-2009, 04:30 PM
I have a 4 flute countersink that has never needed sharpening and still works well. I used it for 4 years working on aircraft and in my shop ever since. That's 38 years now. It's indestructible.

I just had a look at it. The brand is Severance.

11-04-2009, 05:25 PM
That is because it is a Severance brand . That is the only multi flute brand that is good. Yes I have a few of their 6 flute design. But all in all the single flute M.A. Ford is the best. And besides I know you work in a lot of aluminun . The work superb in that . But for all around I still say single flute.

11-04-2009, 06:14 PM
I just looked up Severance and they are still in business (since 1941) and they still make the exact same products.

Here is what they have to say about countersinks:

1, 4 or 6 Flutes?
In general, a six-fluted countersink
will remove more material per
revolution than will a four-flute or
single-flute tool. While the single-
flute countersink is slow-cutting, it
will work well in a non-rigid
machining setup. Four flutes
provide more chip clearance than
six. This is a consideration in
machining stringy materials such as
some plastics and non-ferrous
alloys. Other factors being equal,
the six flute countersink will give
more service life than the four-flute
tool because the cutting load is
distributed over more edges.


11-04-2009, 06:14 PM
i have a couple MA Ford single and multi flute countersinks that i picked up from enco and have been using for several years with good results.

most of them are pretty big and get used to make countersunk holes for flat head cap screws. a 3 fluter seems to work good on aluminum with little or no chatter.

avoid the cheapie hardware store hss 6 flute ones like the plague. they usually have a 1/4" shank and love to snap after about a dozen uses or so...

i tend to use single flute CS's for hand deburring work. i have one 3/4" cs that fit perfectly into a piece of DOM 4130 tubing, so i silver soldered it in and that sees probably 75% of the hand deburring that happens in my shop.

John Stevenson
11-04-2009, 06:54 PM
I found the single flute MA Ford type to be faster cutting with less effort that the multi flutes, some of the multi flutes required a great deal of effort on the handle to actually cut.

One thing in my favour is that I have a very rigid twin spindle drill and one spindle is powered by a geared motor with tooth belt drive to give one speed of 70 rpm, no way this puppy slips.


The very load speed with immense torque and positive drive means it will run these 32mm [ 1-1/4" ] countersinks straight into laser cut 12mm thick steel plates very quickly. As I remarked in another post this was a sub con job and there were literally 1,000's of holes over a period of time.
The part was the base of bar stools that were screwed to the floor, 3 or 4 holes in each in quantities of 500 at a time


If I could have found a countersink any better, at any cost i would have.