# Clock Wheel Fly Cutter



## WMello (Jul 19, 2015)

First try fly-cutter, first clock wheel...





The lathe bit only cut well on the right side. Tried to re-sharpen it and messed up the profile.



The final fly-cutter



After heat-treating, tempering and stoning. My first try



The blank



Set-up on the mini-mill



Started well, but on the 14th teeth, hit the chuck jaw.  Grind it again, but not as good.






Crossing over on the CNC (1/8 end-mill roughing and 1/16 end-mill finishing)



The result. It may even work...

Next week, The Pinion.

Wagner


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## WMello (Jul 19, 2015)

Things that went wrong:

Lathe bit not smooth. Ridges transferred to the fly cutter then transferred to the wheel.

Lathe bit profile not symmetrical. Fly cutter profile not symmetrical, wheel teeth not symmetrical.

Fly cutter hardening and tempering. Not sure if ok. Need tempering oven, more practice.

Rotary table/gear blank mandrel too short. Fly cutter hit the chuck jaw, ruined.

All this caused bad formation of the wheel tooth. The sides are not identical and the surface is not smooth. Also, after damaging and tentative re-sharpening of the fly cutter, the teeth dept was not adjusted and ended up too shallow.

The wheel is 0.6 module, 60 teeth, 1.5" OD, 0.250 bore, 1/6" thick.

Wagner


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## brino (Jul 19, 2015)

Wagner,

If that's your first attempt you should be very proud!

You ended with a decent sample, even if it doesn't meet all specifications.
You obviously learned a great deal along the way.
You recognized and identified several areas of concern.

Many of my first attempts end up in the metal recycling bin and never see the light of the internet.

-brino


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## WMello (Jul 19, 2015)

Hi Brino, thank you.

Thinking about it, I could have made a much simpler lathe bit with just one side; cut one side of the fly cutter blank and, leaving the setup alone, reversed the blank to form the other side. It would be identical to the first. DUH!...

Wagner


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## chips&more (Jul 20, 2015)

You also did a great job of spoking the wheel. I have found that making/running 3 or more wheel blanks works best for me. That way the center one does not have any burrs on it…Good Luck, Dave.


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## WMello (Jul 29, 2015)

Second Try.













Still, not good enough.

The cutter is not symmetrical (again).



Black lines, what it is supposed to be.
Red lines, what i got.

The procedure:






I think this is one of the "Don't Try it at Home" things.

The RPM is way too high, but my spindle (router) minimum RPM is about 8000
The same code was used on both sides of the blank. But the result is not the same. Is this a case of _"Surface hardening" ? _The cutter insert was damaged "out of shape" in the first face ? The sparks sure were not supposed to happen. Try slower feed ? Faster ?

The blank is W1 tool steel 1" OD . Next time will turn it the other way around, from round stock 0.25" OD. The surface speed will then be reduced. The symmetry will be guaranteed, the shape is another story.

The actual wheel cutting:






This is the end of the final pass (each pass is 0.005, I will at least double it next time)

Next weekend, the third try...

Wagner


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## WMello (Aug 3, 2015)

I think I got it


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## WMello (Aug 3, 2015)




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## NEL957 (Feb 12, 2016)

Wagner
Looking real nice, love the CNC for setting blank.


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## TommyD (Feb 13, 2016)

Very nice work even if you don't like it. 

How do you check the profile of the cutter after you are done? I'm assuming the blank is already hardenedby the sparks being produced and the chip strand color, yes? Does the first side cut like the second, sparks and chip color? Same cutter edge used for both sides of the blank? Maybe wear on the cutting edge. How much slop on your mandrel vs hole dia. on your blank?

I used to freehand grind carbide tipped lathe tools, we used an optical comparator to check our form cutters as well as surface grinder wheel forms.


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## toolroom (Feb 13, 2016)

The end results speak for themselves.. Very nice work!


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## WMello (Feb 13, 2016)

Hi TommyD, Toolroom, thank you,

The blank was not hardened at the video. Just in the state W1 come from the supplier.

This did not work very well. My CNC spindle is too fast for steel (8000 RPM min) and the CNC had a problem at the time; the Z axis was "wandering". So the sides of the cutter ended up not exactly symmetrical.

Now I use a different method to cut the profile.

The blank is mounted on the CNC vise inclined to 10 degrees upward to create the relief angle.
I've used a 1/8" 4-flute end mill, shallow cuts and slow feed rate.



The relief is ok in most of the profile, but the faces marked in RED here are "improved" by hand with files and a rotary tool grinder.





The cutters are made of W1 tool steel and water-hardened afterwards.




Wagner


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