Newbie- Using a Fly Cutter

[GeeksGoneBad]

Hi All!

I got a fly cutter set and some HSS tool bits that go with them from Grizzly / Enco - problem is... I don't really know what I'm doing

I thought that I'd just put in the bits and pop the fly cutter into my router that's on my home made CNC and flatten out the face of an aluminum part I cast...

the problems I'm having are:

1- that it vibrates a lot - like it's off balance - should I have to work on evening out the bit so it's balanced? I was thinking it would be adjustable for the radius I wanted...??? - the slowest my router goes is like 8000 rpm - is that just too fast? I thought these things worked better when faster?

2- it's not seeming to work like the videos I've seen on Youtube of flycutters... basically it seems to be not cutting at all and I crashed it twice and didn't want to do anymore til I get a few lessons question is: I'm trying to use the bits right out of the box - am I supposed to grind some cutter head or something?


Thanks for any advise!

[dertsap]

are the bits preground or have you ground them ?
something so off balance as a fly cutter could be dangerous at high speeds , and will definitely destroy your bearings in a hurry ,
reminds me of a boring head that was rev'd up to 10000 rpm , there wasn t a cover it didn t hit when it snapped off from the tool holder

[Donkey Hotey]

8,000 RPM with a flycutter? You're lucky to be alive--seriously. Man, I'm suprised it didn't fling that thing out. I don't think I run flycutters more than about 800-1000 RPM.

I don't run balanced facing cutters that fast. Holy cow! No, 8K is way too fast for anything like that. You might get away with 1/2" endmills but even those will want coolant.

[rando]

Oh man.....would have died to be a fly on that wall.
LMAO!!!!
Wait a minute.....I could have died if I were a fly on that wall.<no longer laughing>

Yeah, I don't think your router is designed to spin a flycutter. Waaaaayyyyyy too many rpms. <wiping the tears out of my eyes as I pick myself up off the floor>

This one is really a gutbuster

[Donkey Hotey]

This is what flycutting should look like on an actual mill (much more rigid):

YouTube - Surfacing 6061 Aluminum with a Fly Cutter - Tormach CNC

YouTube - Surfacing 6061 Aluminum with a Fly Cutter - Tormach CNC

[laszlozoltan]

you really have a lot to learn- I don't mean to say that in a discouraging way, but that there is a lot to learn, and personal safety is foremost. Honestly, the best way to learn is to get some hands on in a machine shop.

[nwrepair1]

Need more details as to size of router motor. I replaced the vacuum top on my router with a 1" sheet of k100s aluminum and fly cut it with my 2.5" flycutter at 8000 rpm with cutting oil sprayed on the surface. I could go through my files and find the g-code to see what the depth and travel speed was if it would help.

[DareBee]

Originally Posted by nwrepair1 Need more details as to size of router motor. I replaced the vacuum top on my router with a 1" sheet of k100s aluminum and fly cut it with my 2.5" flycutter at 8000 rpm with cutting oil sprayed on the surface. I could go through my files and find the g-code to see what the depth and travel speed was if it would help.

With a single point HSS cutter?
That is absurd.

[GeeksGoneBad]

Nope the bits are right out of the box - I did not grind them... Is there is a good image out there as to what the tip should look like?

I've seen a few posts and other things online that led me to believe faster was better with a fly cutter which is why I tried at all and at least the post by nwrepair proves I'm not TOO far off the wall

about safety though ... I did have a shield up between me and the router/fly cutter

I tried a router speed control to see if I could slow it down - unfortunately it didn't work with my Hitachi M12VC router...

I do have a lot to learn and I missed this hobby by about 6 years because my father used to be the manager of a machine shop before they went out of business! Wish I'd had this bug then!

[ImanCarrot]

Vibration= out of balance, it will wreck 1) your machine, 2) yourlab if something comes loose, 3) your health if something comes loose.

Be very carefull man.

I ran an 8 inch diameter flycutter at 20K RPM (yes 20,000) on an air bearing spindle- the tool (a single point diamond on a 1.5" long shank) came loose and it went through the machine enclosure like a freaking bullet. Scared the **** out of me, I stopped shaking about a week later.

Also, make sure you're not cutting on the back stroke. It's better to have the head slightly angled (very slightly) so that it definately does not cut on the backstroke which will wreck your tools and give a bad finish. Of course this means cutting in one direction only. I notice on that video that the tool was cutting in both directions. The first direction was climb cutting (good) the second was conventional cutting (bad for tool wear). Mind you I didn't really have that problem, mine skimmed the whole surface in one pass.

[tc26]

Learn to work with SFPM and tool diameter to calculate RPM.
Here is a link to a speed and feed calculator. Below the calculator is a chart with recommended speeds for different material/cutter combinations.

http://www.whitney-tool.com/html/cal...SpeedFeed.html


Here is a link to a book that has a chapter on free hand grinding of single point HSS cutting tools. See chapter 5.

http://tabletopmachinewiki.com/wiki/...nery_Repairman

[dertsap]

Originally Posted by nwrepair1 Need more details as to size of router motor. I replaced the vacuum top on my router with a 1" sheet of k100s aluminum and fly cut it with my 2.5" flycutter at 8000 rpm with cutting oil sprayed on the surface. I could go through my files and find the g-code to see what the depth and travel speed was if it would help.

running those tools at that speed is a death wish
one of these times that tool will come in contact with the work and it will come out like a gernade , its not a matter of if it could hapen ,its a matter of when it will
i dont have too many qualms when it comes to dangerous stuff but there is a difference between doing stuff that may hurt me or the stuff that may kill me , i like to avoid the stuff that may kill me