Countersink/deburr tool

[REK Knives]

What do you guys do with your's when it goes dull? And why is mine going dull so fast? Barely made one sink in a ti scale and it's dull. I've got the interstate set from mcmaster carr I believe.

 

[P.Brewster]

Can you be more specific about the tool?

To countersink and chamfer annealed steel, I use a single-flute US-made HSS or cobalt countersink (I like the KEO brand). I run it at the slowest RPM I can, which is 300 on my drill press. I generally use Boelube paste lubricant. I resharpen by carefully grinding the inside of the flute - I never touch the conical outside surface.

To countersink and chamfer steel at 50 RC, I use a 3-flute, I don't attempt to resharpen, but everything else I mentioned above is the same.

You could be talking about a hand-operated deburring tool, or a "zero-flute" countersink - I don't know. Also it matters if you are countersinking an existing through-hole, or machining a conical dimple in solid metal.

 

[REK Knives]

Thanks for trying to help me man! This is what I ordered I believe. Would there be a different kind that would be easier to sharpen or better for titanium?

 

[P.Brewster]

Thanks for trying to help me man! ... is what I ordered I believe. Would there be a different kind that would be easier to sharpen or better for titanium?

Those are often called "zero-flute countersinks." I know some people swear by them - I've tried them in my shop, and previously at a day job working on 304 stainless. I never had any luck with them.

Try a single-flute countersink that is US-made (use-enco.com and mscdirect.com will show brand and country-of-origin, mcmaster often does not). KEO and M.A. Ford are great brands. Get HSS or cobalt if you can afford/find it. Use a slow RPM (on 304 stainless we would run them at ~100 RPM - super slow) and oil or coolant. Don't baby the downfeed. I like paste lubricants on countersinks - coconut oil would work!

If that doesn't work well, try a 3-flute.

 

[ron_m80]

^agreed. Not the countersink you want to use.

From the style you used, I would assume you are countersinking holes to make frames lighter, not for hardware use.

 

[REK Knives]

Thanks guys. I am basically wanting to be able to mirror or high polish finish the inside lip/ring on existing holes. Like this:

 

[ron_m80]

A coutersink followed with a Cratex polishing bit would do it.

 

[Matthew Gregory]

Josh, another (sort of messy) way to do this is to make a wood dowel that tapers to the approximate dimension of your chamfer, and use valve lapping compound. Just chuck the dowel I to a drill press or something and go to town. Might give you the shine you're looking for.

 

[Drew Riley]

I've never tried those zero flutes, and the single flute I used in my drill press seemed like it just wanted to chatter all day long. I've had best luck with 6 flute countersinks.

I've also seen guys use step drills with some degree of success, depending on thickness of material and hole diameters...

 

[REK Knives]

Thanks guys, looking up the Cratex bit now...

Matthew, that's a great idea! Thanks!

I've never tried those zero flutes, and the single flute I used in my drill press seemed like it just wanted to chatter all day long. I've had best luck with 6 flute countersinks.

I've also seen guys use step drills with some degree of success, depending on thickness of material and hole diameters...

Yeah, the ones I got were specifically because they dealt the best w/ sloppy spindles, and I'm using a cheap ryobi drill press =) so the 6 flute would work well?

 

[Drew Riley]

Thanks guys, looking up the Cratex bit now...

Matthew, that's a great idea! Thanks!



Yeah, the ones I got were specifically because they dealt the best w/ sloppy spindles, and I'm using a cheap ryobi drill press =) so the 6 flute would work well?

Seems to work best for me given the options. Depending on spindle slop/runout you may still get a little chatter. Just follow up with Matthew's suggestion and you should be fine.

Try not to overheat, and use a little bit of cutting oil to clear chips and it should last a good while.

 

[REK Knives]

Seems to work best for me given the options. Depending on spindle slop/runout you may still get a little chatter. Just follow up with Matthew's suggestion and you should be fine.

Try not to overheat, and use a little bit of cutting oil to clear chips and it should last a good while.

Very cool. Can you sharpen these yourself when they go dull?

 

[Drew Riley]

I have in the past, but normally I'll just buy a new one.

That said, they normally last me a pretty long time. Just don't try them on hardened steel.

 

[REK Knives]

A coutersink followed with a Cratex polishing bit would do it.

Ron, I found the Cratex polishing sticks but the size I would need is larger than my chuck (I need 5/8" or 3/4") so since I don't have a lathe I can't turn it down unfortunately. I think I will give the dowel rod thing a try, it will be crude but hopefully work the same!

I have in the past, but normally I'll just buy a new one.

That said, they normally last me a pretty long time. Just don't try them on hardened steel.

Wasn't planning on it! thanks for all your help.

 

[ron_m80]

I have an old box of Cratex bits I got with a machine deal. Let me see what's on the shelf in the shop after work. I'll PM you if I think something might work. These cratex bits screw onto a mandrel, like a buffing wheel does.

 

[REK Knives]

I have an old box of Cratex bits I got with a machine deal. Let me see what's on the shelf in the shop after work. I'll PM you if I think something might work. These cratex bits screw onto a mandrel, like a buffing wheel does.

Thanks man, very kind of you to check into this for me!

When I looked it up on msc they just had cratex polishing sticks so that's why I was confused hehe.

 

[ron_m80]

I have a red and green cone, its 1" at the base and .3" at the top. Angle looks about 30° ish. They take a 1/4" - 20 mandrel.

PM me if your interested.

-Ron