Project 2: Fly Cutter

[jmiller]

After making a set of vise jaws using only an end mill for facing I've decided to make a fly cutter as my next project. I started with 2" round bar of mystery metal which I assume is probably cold rolled steel.

I cut a piece off about 3 1/4 inches. After facing it off came the arduous task of turning the 3/4 shank on my lathe.

This metal was very stringy. Using a carbide insert, I played with my feeds and depth of cut to try and manage the chips. I found that .025 depth of cut and cutting fluid made it manageable, and I stopped the cut often to clear out chips as they built up. At one point I tried .040 DOC and the workpiece came loose from the chuck. I had to reseat it in my 3 jaw and spend about 15 minutes trying to tap it back into concentricity. I got to .001 runout in 3" and continued to turn it down.

After a couple hours of work I ended up with this. The shank is .751 and 2" long. Fits right into a 3/4 collet. Surface finish is very nice. Tomorrow I'll move over to the mill.

I'm really enjoying the process of learning my machines and using them craft things that I can then use to create more.

 

[T Bredehoft]

Any one of us would be proud of your work, so far. Keep it up.

 

[Martin W]

Nice job! Nice surface finish.
Any way you could center drill and use a live center in your tailstock? Would be stronger. Probably wouldn't have come loose.
Just looking out for you. Safety wise.
Cheers
Martin

 

[jmiller]

Nice job! Nice surface finish.
Any way you could center drill and use a live center in your tailstock? Would be stronger. Probably wouldn't have come loose.
Just looking out for you. Safety wise.
Cheers
Martin

Oh man, i actually thought about that while I was facing off the end. I think I just got too excited and completely spaced it.

 

[jmiller]

I have to say I was nervous about this operation. Clamping a round object, at an angle, and Ive only milled aluminum thus far. However my setup held strong and my feeds and speeds seem to be fine. Other than dodging hot chips like Neo in the Matrix, I dont think that could have gone any better.

At first I was milling with the work moving away from me causing the cutter to fling its bits right at me. I eventually switch directions and that cut down on the chip shower signicantly.


Everyone loves those action shots:

 

[Janderso]

Looking good so far.
What angle did you use? There seems to be many shop made fly cutters with different specs but they all seem to do a good job.
The surface finish can be very good with the right cutter.

 

[jmiller]

I used 15 degree angle on the body. Im going to slot it for a 3/8 tool bit

 

[Rex Walters]

That second photo with the long stringy chips looked terrifying! I thought it was a MUCH bigger lathe and chuck, though. At first glance that somehow looked like a ~6" diameter bar in the bandsaw!. I'm watching too much youtube with big boy machine tools. (laugh)

 

[jmiller]

I feel like I milled this backwards and accidentally made an Australian fly cutter.
Everything spins in the opposite direction down there right?
In my head I had the larger mass behind the cutter and the screws pushing with the cutting force. A quick google search shows them milled both ways and some even milled on both sides of the cutter. I guess I could still mill the other side off as I havent yet drilled for the set screws. I have a pretty nice fit on my 3/8 tooling so it would only push the cutter off center a few thou. Will any of this matter or should I just roll with what I have?

I did make an error and forgot to divide the cutter width when I began slotting. Luckily I have a pretty thick body on this so I just cut my slot in the correct spot .100 deeper then came back and faced it off flush again.

 

[7milesup]

Very nice work!