Fly cutter questions

T

Taximanny

Joined
Jul 27, 2015
Messages
460
I'm not a machinist by any sort.
Last year I purchased the harbor freight mini mill. I have been using it solely for relieving liners.

I'm now trying to use it with fly cutter for nail nicks.
It is HSS and it takes me nearly 45 min. To cut a nick in 01 Tool steel.
I have watched about every fly cutter video and don't know if it's the way I sharpened it or what.
I'm not losing the tip, it's holding the shape fine. But it takes forever.

I'm not getting chips out but very very fine grain metal as it's cutting.

I'm trying to get away from the stone that I have been using to cut my nicks.

Should I be using carbide tips?
Will the cut faster?

By the way I'm using the slowest speed and feed possible.
 
I assume the O1 is annealed?

Do you have a picture of your bit and/or setup? Sounds like POSSIBLY incorrect sharpening geometry, or it may just be a feed/speed issue.
 
What diameter is it set at? What size is the HSS blank? What kind of radius do you have ground on the tip? Pictures or video would help.
 
I'll see what I can do


Sorry no video...
all I can gather and think is it is blade geometry...

The final nail nick is great but can't understand why it takes so long.
I have tried all speeds but have settled with very slow. With lots of oil.
I've read and watched most everything about blade geometry.
And do believe I got it close.
Maybe???
 
That radius is far too large. Try something like this. I would also shorten the cutter up as your machine isn't very rigid. At the arrow, that tip should have a .015 - .030 max radius.

1zbuz2f.jpg
 
kuraki said:
That radius is far too large. Try something like this. I would also shorten the cutter up as your machine isn't very rigid. At the arrow, that tip should have a .015 - .030 max radius.

1zbuz2f.jpg
Click to expand...

He's cutting nail nicks, not surfacing material. It's a different geometry for a completely different application.

The side profile doesn't look terrible, but what about relief? Is the cutting edge straight across? In other words, if you position your tool bit perpendicular to your blade face, and run your table in until it touches, does the entire cutting edge touch the blade, or just a point? You really need some back rake/relief angle so that just the leading corner is doing the cutting, and not the entire edge of the bit, if that makes sense.
 
knife to a gunfight said:
He's cutting nail nicks, not surfacing material. It's a different geometry for a completely different application.

The side profile doesn't look terrible, but what about relief? Is the cutting edge straight across? In other words, if you position your tool bit perpendicular to your blade face, and run your table in until it touches, does the entire cutting edge touch the blade, or just a point? You really need some back rake/relief angle so that just the leading corner is doing the cutting, and not the entire edge of the bit, if that makes sense.
Click to expand...

Yes I do have relief in all the angles the way your describing.
I don't have a slight radius on the point though...
 
DOWELLKNIVES said:
I use a carbide tip. It only takes 15 seconds to cut a nick. Your profile looks off a bit too.
Click to expand...

I did play with the profile on screen me aluminum stock to get the nail nick shape I was after.
If the is what you are preferring to.

Are you using full size machine ?
Do you have a pic ?
Is the carbide a screwed on tip ?

I would definitely go that route if it would speed things up.
I'd be happy with it taking 5 min rather than 45.
 
I see the profile your talking about now...
and I'm guessing the hole tool is carbide??

i would like to get some sort of shaving out of the cut rather than a speck of dust.

Or I'm thinking take it to a machine shop that knows what there doing and have them set my angles.
 
knife to a gunfight said:
He's cutting nail nicks, not surfacing material. It's a different geometry for a completely different application.

The side profile doesn't look terrible, but what about relief? Is the cutting edge straight across? In other words, if you position your tool bit perpendicular to your blade face, and run your table in until it touches, does the entire cutting edge touch the blade, or just a point? You really need some back rake/relief angle so that just the leading corner is doing the cutting, and not the entire edge of the bit, if that makes sense.
Click to expand...

I see now. I didn't realize what that meant.
 
Here's some 2 cent advice from a someone who has only cut a few nicks with a flycutter on a small mill (PM25MV). Small machines lack rigidity, so try less stickout of the toolbit. Hone your edges nice and sharp, have a small radius. I think sharp HSS on a small machine may even be better than carbide.

I even stalled my machine by taking too large a cut. But was able to get a decent knick in about 5 passes, advancing maybe .005 per pass.

I know I can get them better with the same setup, but they were nice looking and functional, even if not as deep as I'd like.

Hope that helps a little.

Barret
 
knife to a gunfight said:
The side profile doesn't look terrible, but what about relief? Is the cutting edge straight across? In other words, if you position your tool bit perpendicular to your blade face, and run your table in until it touches, does the entire cutting edge touch the blade, or just a point? You really need some back rake/relief angle so that just the leading corner is doing the cutting, and not the entire edge of the bit, if that makes sense.
Click to expand...

It looks to me like Knife to a Gunfight is correct. It could also be the camera angle, but that cutter doesn't look right for what you are doing. It does seem like you are missing relief and you are probably cutting with the back of the tool bit as well. the tool bit should be nice and sharp (stone it), not just rough ground on a belt grinder.
 
Ok I reshape it to look more like Brets
For some silly reason I thought I had to have a radius on it to get a radius on the nick bottom.

It's now taking about 5 min or so because I have a mini mill and I don't want to force feed more than it can take.
The bottom nick on the tool steel is the before and the one on top is the after with the new shape on the cutter.

 
beautiful nick! it also looks cleaner than in the previous tool setup.
I can't wait to stash enough money to get myself one of those mini mill!!!
Did any of you ever get any cracks hardening the blades with those sharp nicks?
 
stezann said:
beautiful nick! it also looks cleaner than in the previous tool setup.
I can't wait to stash enough money to get myself one of those mini mill!!!
Did any of you ever get any cracks hardening the blades with those sharp nicks?
Click to expand...

Never had an issue
 
I've never cracked around a nick either, but a very slight radius on the cutting point should add a little insurance as well.
 
knife to a gunfight said:
I've never cracked around a nick either, but a very slight radius on the cutting point should add a little insurance as well.
Click to expand...

That would be blasphemy!! ;) LOL
A real deal nail nick has to be needle point sharp! That's why i can't wait to have a similar setup, and why i am so happy i shouldn't worry to much about them being stress risers.

It is incredible how the slight mod of the cutter's shape has so much influence in the operation
 
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