Project 2: Fly Cutter

[jmiller]

Welp, here she is, le piece de resistance.


When I fist chucked it up in the mill it had about .010 runout. This is probably for to me only having a 3 jaw chuck and not turning with centers. I put it back on the lathe and shaved off about .012. I know my mill is good for a half thou runout and I can always count on the lathe for at least a thou. In the end I got it to spin with a hair under .002 runout in the mill. I figure this is probably fine. All i could do to improve it further would be to turn the body once more using the mill itself. Probably overkill, but its its an option should I need it.

Only thing left now is to grind a tool and give it a whirl. I'm debating on whether to blue it or not.

 

[jmiller]

I think I'll call this one a success. I ground the bit to the geometry for a fly cutter on Tom's Techniques. Found a beat up piece of aluminum scrap and let her rip. I have to say I'm thrilled with the results. My x-axis power feed should be here on Thursday and this cutter should be able to handle up to 6" parts. Facing material will be a pleasant experience now that I'm actually looking forward to. And judging by the finish I did a pretty good job tramming the mill in.



So whats the next project? Im not really sure. I really want a boring head...

 

[woodchucker]

I see the angle, but what I don't understand is how you cut the angle?
It looks like you had it gripped by the V vertically. And the groove is being milled front to back.. so how did you get the angle? Just curious.

Also, avoid putting a sharp corner from the holder to the shaft. You want a slight radius... hard corners become stress risers.. probably not an issue here, but I just wanted you to be aware that when we can we want a smoother transition so that stress can be relieved instead of concentrated.

 

[jmiller]

I see the angle, but what I don't understand is how you cut the angle?
It looks like you had it gripped by the V vertically. And the groove is being milled front to back.. so how did you get the angle? Just curious.

Also, avoid putting a sharp corner from the holder to the shaft. You want a slight radius... hard corners become stress risers.. probably not an issue here, but I just wanted you to be aware that when we can we want a smoother transition so that stress can be relieved instead of concentrated.

Hopefully this view helps. I set the angle with a simple angle gauge referenced off the top of my vise jaw. Then milled flat left to right.

Radius comment duly noted.

 

[T Bredehoft]

There's no magic in the angle of the cutter in the holder, it does come into play between the work and the cutter, but that's independent of the holder.

 

[woodchucker]

I finally see it this morning, that pic of the first cut, was not a groove, it was the first cut.
I see the light.

 

[jmiller]

I decided to cold blue my fly cutter. I dropped it into a cup of oxpho-blue with giddy excitement and anxiously awaited the chemical reaction. I've had great success with this stuff in another project and really liked the way that turned out.

10, 20, 30 seconds go by and nothing was happening. This is used bluing that I had rebottled. I thought to myself maybe it has gone bad or inert or something. I test a piece of known cold rolled and it blackened almost instantly.

It appears I unknowingly made this fly cutter out of what I assume is stainless steel of some variety. I find this kind of funny because I was nervous about working with stainless steel. I understand it can be more difficult to machine. This is also means I have a 2" round over a foot long of stainless stock, which is good to know.

 

[Rex Walters]

It appears I unknowingly made this fly cutter out of what I assume is stainless steel of some variety.

I thought those scary chips in the photo in the first post looked like stainless!

 

[jmiller]

I thought those scary chips in the photo in the first post looked like stainless!

This particular alloy is quite magnetic. A small rare earth magnet can hold it up. I havent weighed the cutter yet but its got some gravity in it.

 

[mmcmdl]

A perfectly trammed head will give you a cross hatched pattern ( which you have ) . Nice job !