A double edged fly cutter.

[ncollar]

Tony
Very nice, I making one from some 1 inch cold roll, it's 5 inches in diameter with a shaft heat shrink in place, I just found what I'm going to use for a cutter. A nice big fly are nice to grab and mow it nice and flat. As soon as I can I'll post pictures.
Nelson

[Woodgeezr]

thanks. where did you find the R8 to chuck mounting flange?

[tonyfoale]

thanks. where did you find the R8 to chuck mounting flange?

Probably from Discount Machine (Shars) on eBay.

[tonyfoale]

Tony
Very nice, I making one from some 1 inch cold roll, it's 5 inches in diameter with a shaft heat shrink in place, I just found what I'm going to use for a cutter. A nice big fly are nice to grab and mow it nice and flat.

Nothing like some decent inertia. Good luck with it.

[hobbybob]

Nice tool! I'm sure i will make one myself.
Thanks for charing!

[Toolmaker51]

I'll reiterate my comment on setting multiple bits, in cutters that hold bit and allow adjustment, unlike insert tooling.
Very first, inertia is what makes flycutting work. Increased mass propels the cutter and reduces deflection as cutter enters. Not degrading the smaller commercial style bodies, they have a place too.
But first, let this image form...When setting something like engine valves, those surfaces are comparatively smooth and broad, even oily and a gauge slides easily between.
A double fly cutter most often carries tools two different radii from the body centerline, but same radius at two different heights works too. Either way, interpret what follows with that in mind.
Touching off a first cut's easiest when feeler gauges are used. Instead of just one though, in the traditional sense, use two.
The sharp point of a cutter understandably doesn't offer the same 'feel' as lashing valve trains. The bit is certain to scratch or grab the leaf with the tiniest increase of pressure. With two leaves, moving only the lower leaf now slides in a far smoother manner, isolated from the sharp cutter. Let's use .010 and .003 as the slip as example, though the total isn't important. I like the .003 being just thick enough to push not bending immediately when clearance is borderline.
Now, set the second cutter, typically the finisher first.
Next combine one leaf [.010] with a different thickness, perhaps .008, in accordance with amount desired to rough with the leading cutter.
Add the gauge thicknesses of first pair involved [= .013], raise the knee or lower quill that amount minus [-] .001.
If your tactile sense is good you'll be .001 above the material. I often take a trial pass to insure visibly the surface is parallel with cutter plane. Marking with dye isn't a bad idea. It'll reveal uncut portions if RPM and feed rate aren't proportionally moderated.
Whether skimming minimally or registering dials for more aggressive removal, it's going to be far closer to predict intended remaining material.
There are tendencies to run excess RPM, shallow cuts and too slow feed rate. One clue is material re-welding itself instead being swept away - the small chip subject to more heat than it can dissipate. Coolant with fly cutting tends to be messy!

[marksbug]

as always awesome!! Im with you on heaver fly cutters. the cutter head on our old Storm Vulcan 85b for serfacing cylinder heads and cylinder blocks. used a 18-20" head with about 24 cutters on it all stagered.they do a awesome job.I have planed on making a plunge fly cutter for my aircooled vw stuff very simular to what you have there but the cutters wont be different hights. most that are made to do it are iMHO not heavy enough, some not ballanced.and most dont do a good job.I have a set of them in diferent bore sizes but I dont really like them,so...Ill make one I like. plung cut, no sweep and cutting across the entore blade width can have issues..thus Im trying to eliminate the issues for a better finish. Ive used a smaller flycutter and used a rotery table to spin the head but thats a lot of extra work .I do wish I had cnc but I dont so ....I do what I can do. keep up the great work!!!