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Quality countersink(s)

slow-poke

slow-poke

Ultra Member
Okay I have come to the conclusion that cheaping out on no-name countersinks is just an exercise in wasted money.

Suggestions for something that will keep working after more than 10 holes in steel, because that's about how long the latest set lasted.
 
Lets keep it really simple.

1. Speeds and feeds extend life or ruin life of tooling.

2. Lubrication or cooling fluids.

3. Go carbide.

4. 1&2 also apply to 3.
 
Not always the case......witnessed by some of our esteemed fellow members who shop for the cheapest deals everywhere and do exceptionally well.

I've bought Dollars store tools and tooling for one task and prayed they last that long. Some have far exceeded their hoped for life along with premium expensive tools and tooling even after extreme continue use and abuse.

What I have learned is how to make it work.
 
What range of sizes? Lots of permutations and combinations when you factor in:

HSS, cobalt or carbide?

Single, zero or multi-flute?

82, 60 or 90 degrees?

My current selection of countersinks came from auction box lots. I like how the zero flute countersinks cut steel--no chatter. I don't have enough experience with other materials to have a preference. But I don't think zero flutes are appropriate for, say, wood.

I would, however, avoid BusyBee. Before I got my current selection, I had a project that required countersinks for 3/8" flat head screws in mild steel which was bigger than the lone countersink I had at that time. The BusyBee 3/4" countersink ($9) came a 1/4" shank--which kept slipping in the chuck. Then the flute chipped and folded over before I had the second hole done. Usually I keep broken HSS stuff in case it can be repurposed in the future. This piece went straight in the trash.

YMMV

Craig

Maybe @SomeGuy wants to set up a tool test? ;)
 
trlvn said:
What range of sizes? Lots of permutations and combinations when you factor in:

HSS, cobalt or carbide?

Single, zero or multi-flute?

82, 60 or 90 degrees?

My current selection of countersinks came from auction box lots. I like how the zero flute countersinks cut steel--no chatter. I don't have enough experience with other materials to have a preference. But I don't think zero flutes are appropriate for, say, wood.

I would, however, avoid BusyBee. Before I got my current selection, I had a project that required countersinks for 3/8" flat head screws in mild steel which was bigger than the lone countersink I had at that time. The BusyBee 3/4" countersink ($9) came a 1/4" shank--which kept slipping in the chuck. Then the flute chipped and folded over before I had the second hole done. Usually I keep broken HSS stuff in case it can be repurposed in the future. This piece went straight in the trash.

YMMV

Craig

Maybe @SomeGuy wants to set up a tool test? ;)
Click to expand...

I would, but I don't have enough types on hand...I have single flute and those typical solid ones you get at the hardware store...and I also sometimes use a regular drill bit in a larger size.
 
I guess 82 degrees is most common?

Size suitable for M4-M8, or 1/4 - 3/8 SAE

The cheaper ones seems to survive in aluminum for a while, so I really need something suitable for steel not sure if I should get HSS or something harder?
 
slow-poke said:
I guess 82 degrees is most common?
Size suitable for M4-M8, or 1/4 - 3/8 SAE
The cheaper ones seems to survive in aluminum for a while, so I really need something suitable for steel not sure if I should get HSS or something harder?
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Metric flatheads are 90-deg. Imperial flathead UNC/UNF are usually 82-deg. Screws for brown stuff were also typically 82-deg but the world is changing (or has years ago & I missed it). Metric wood screws replacing numbered screws, different head profiles... anything goes nowadays.

HSS is perfectly fine for alloys & mild steel, its been used that way for decades. But it has to be decent quality & pay attention to speeds & feeds & fluid & ..... Carbide is harder than HSS variants, so will similarly cut these materials & extend into range of semi hardened tool steels. But carbide tools have a harder, more delicate edge so more prone to chipping. So setup & rigid cutting conditions must be controlled. Sometimes carbide is the same price as HSS, sometimes it can be very expensive. Really depends on what you are looking at. Its predominantly used in industry over HSS so basically hobbyists are indirectly benefitting by that. Sharpening carbide requires specific wheels & abrasives unless you can job it out or OK to replace it.
 
I’m really liking the 3 flute design (sourcing from MSI in Edmonton, made in Germany). Yes, expensive, work great. Available in the usual angles and various sizes.
 

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I have an unbranded hss 3-flute countersink made in Yugoslavia. I’ve been using it on pretty much any material hard or soft, for over 25 years…. It’s still sharp and cuts chatter-free. Much better quality than most Chinese tooling. No idea where I got it though, but I’d like to get some larger sizes of same type.

20231206_204655.jpg
 
I have a good quality butterfield countersink which produce a nice finish on the mill or the lathe. The cheap ones don't seem to work well at all in my machines. They leave lots of chatter marks. Recently I started using them in my cordless drill on the very low speed and have gotten some acceptable results. I think the low speed and the fact I using them free hand allow for correction to find there sweet opperating spot. I wouldn't be surprised they would work even better if I was able to drive them with a somewhat rigid rubber hose, to act like a flexible shock absorber. They don't seem to like rigidity.
 
PeterT said:
Metric flatheads are 90-deg. Imperial flathead UNC/UNF are usually 82-deg. Screws for brown stuff were also typically 82-deg but the world is changing (or has years ago & I missed it). Metric wood screws replacing numbered screws, different head profiles... anything goes nowadays.
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And aircraft hardware is 100 degree.
I find it hard to imagine that any of the those mentioned 3 degree countersink angles would not work just fine in all applications if matching screw and countersink were used.
 
fixerup said:
I have a good quality butterfield countersink which produce a nice finish on the mill or the lathe. The cheap ones don't seem to work well at all in my machines. They leave lots of chatter marks. Recently I started using them in my cordless drill on the very low speed and have gotten some acceptable results. I think the low speed and the fact I using them free hand allow for correction to find there sweet opperating spot. I wouldn't be surprised they would work even better if I was able to drive them with a somewhat rigid rubber hose, to act like a flexible shock absorber. They don't seem to like rigidity.
Click to expand...
Even good CS's can chatter if speed is too high or if unsupported. Low speed & rigid setup usually gives the best results in finish & accuracy. But a cheap CS usually exposes a few potential problems. Usually its a bad grind grind job where the edges are unequal, or wrong cutting angles. If geometry isn't right then it almost doesn't matter what the material is. I'm starting to redress some bad import tools & actually the steel is perfectly good HSS. Some are actually distorted runout you can measure with DTI - as though they were finish ground, then heat treated (vs the other way around). Or maybe when the special miracle coating was applied.

I also use a cordless drill for simple & quick hole deburring or shallow countersinking. I find the single flute (or what they call zero flute) work the best. I also have some multi-flutes that work excellent in lathe or mill but not nearly as well on a hand drill. Why? Because even though the drill is capable of same low speed, it is relatively free to float axially under your hand pressure. So once any edge digs in just a teeny bit, this initiates a repetition pattern by the next edges that feeds on itself & exaggerates to the ugly chatter/star pattern. Zero flute makes a single cut more like a lathe tool. They work equally well on lathes & mills too, but removal rate is lower & technically the edge angle is a bit different as a function of where contact is relative to hole. And they are tricky to redress because its a progressive helix relief angle. Single edge are a bit easier to redress, you do the primary edge, then its all relief behind that. D-bits are basically single edge cutters.

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Janger said:
These from KMS are pretty good, I have a set. Irwin. https://www.kmstools.com/irwin-5pc-countersink-set.html

IRW-1877791_LRG.jpg


But @Dan Dubeau made a connection in my head I didn't conceive of till he pointed it out in another thread. Thank you Dan. I always thought they just were for starting holes and centre drilling for tail stock support.

These things
DB-DC1_LRG_3.jpg
are the same as these but for metal. Ah.
MILE-5341_LRG.jpg
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It was years before I discovered they came in included angles different than 60* and could be used like that too. Glad I make the connection. That kind of stuff is what makes forums so great for learning.
 
Janger said:
I always thought they just were for starting holes and centre drilling for tail stock support.
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I originally only intentionally used them for starting holes and drilling centers for supports too. However, I did accidentally over drill them a few times and discovered their use as a screw head countersink.

The forum introduced me to spotting drills and I've never looked back.

I still think socket head screw countersinks are all messed up. Too big for the screw head and too big for the unthreaded shaft too.
 
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