What Did You Buy Today?

pontiac428 said:
Me too. I've gotten good at making single flute countersinks. I also get good results with D-bit countersinks, they're easy to make for any angle, but tricky to center on the mill table compared to a full conical c'sink. Best finish bar none is O-flute. O-flutes aren't picky, as long as the cutting edge has a little bit of lead. Multi-flute c'sinks chatter no matter what, so I only use them for deburring or chamfering if I have to using a hand drill. They're great for that, because they tolerate misalignment well.
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I bought it to use on the mill for de-burring and chamfering holes, wanted carbide so I can run it a bit faster which I usually get better results from.
 
verbotenwhisky said:
Here it is, Made a mistake, it is 3/4"... still shinny though...

View attachment 446730:cool:
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Jeff, do you run it slow. Now that I have a vfd, I find it so much easier to chamfer using counter sinks, 45 cutters, and round overs. I dial it all the way down to 250 or so for a hole.. Or I will do about 1000 for a traveling cut, but feed slowly. But it all depends I guess on the material, and the rigidity of the setup. I also have been using climb cuts more often, so it floats out of the cut, rather than dig in.. it took me a while to adopt that stance. Now I finally understand.
 
pontiac428 said:
Me too. I've gotten good at making single flute countersinks. I also get good results with D-bit countersinks, they're easy to make for any angle, but tricky to center on the mill table compared to a full conical c'sink. Best finish bar none is O-flute. O-flutes aren't picky, as long as the cutting edge has a little bit of lead. Multi-flute c'sinks chatter no matter what, so I only use them for deburring or chamfering if I have to using a hand drill. They're great for that, because they tolerate misalignment well.
Click to expand...
I'll have to try making one. I have a D-bit grinder
 
You can almost get away with zero back clearance on a D-bit countersink... almost.

I knew I had a pic somewhere. I made up several of these in different sizes of drill rod (but O1 works too). I ground different angles on each end to cover the usual 45 and 60 degree sinks. They work very well, other than the caveat that D-bits are slightly harder to eyeball alignment on. They also work as spot drills, but they take occasional sharpening because spotting is rough on the tool tip.

Didja know I like D-bits?

IMAG0356.jpg
 
And to clarify how I grind the single facet leade and back clearance (applies to ALL D-bits), here's a drawing.

The grey is the bit, the white space is ground away. The green shows that the facet is a 15 degree step.
dbit.png
 
Aaron David said:
A Diana 45 in .177. This is one of the better German air rifles from the eighties. She is a real sweat shooter, especially with the diopter sight I pulled out of my parts bin. Air guns are great because I can shoot them in my basement before my wife gets up in the morning.
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I'm jelly!
 
pontiac428 said:
And to clarify how I grind the single facet leade and back clearance (applies to ALL D-bits), here's a drawing.

The grey is the bit, the white space is ground away. The green shows that the facet is a 15 degree step.
Click to expand...

John, is this drawing from the shank perspective, or is it for use in one of those left-handed lathes I keep hearing about?

Brian
 
mattthemuppet2 said:
Those multi flute countersinks work fine as long as you feed them hard enough. I view them like parting tools - turn slow feed hard
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I do well running at 500 to 800 RPM for bearing and chamfers but the HSS counter sinks do not survive that in the mill, I will let you know how the carbide does. I have a .500 90 degree chamfer cutter for the straight edges which works well for that.
 
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