Carve 3D model With A V Bit?

Has anyone carved a complex 3D model with a V bit? I’ve used tapered ball nose bits before but am wondering if anyone has experience using a V bit for this purpose. Am I crazy for wanting to try this? I bought a 15 degree .005 diameter tip V bit. I’m using a shapeoko so I don’t even know if the machine has the resolution to do a 50% step over. Thanks for any thoughts!

If that’s 0.005 inches then that’s 5 steps at native 0.025mm step size.

You’d be wanting to do most of the cutting with the side not the tip of that bit though as it will go blunt or ablate away pretty quickly at that size.

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I’ve not done this with a V bit, but I have with a small flat endmill… it ended up better than I expected (and flat areas were very nice)

You might need some special software tweaks to make this work… but it’s not insanely hard for the software to support… just unusual.
If you’re having a hard time finding software to generate the gcode, I could add support to the browser based STL-to-gcode tool I’m building.

Do you know if your V bit is flat at its point, or is it more like a ballnose ?

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I assume you want to carve a very small area (like a coin or something) since otherwise, with such a super small stepover, you could be cutting for a few weeks :wink:

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Haha love it. Just curious about how detailed I can get with CNC carving. A coin would be a good idea to test :thinking::+1:t2:

I’m not sure. I have the Amana Tool 45611-K. I couldn’t find a spec saying whether or not it is flat or rounded and I don’t have magnification powerful enough to see with my eye. I use fusion 360 but haven’t tried to generate a tool path with this tool yet so I’m not sure what the software will think of it.

Yes .005 inches. I was thinking I would only use it for extremely fine detail work. The thought I had would be to rough out material with a flat end mill, finish with a tapered ball, and then use this v bit to finish the super fine details.

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Be interesting to see how it works out.

fenrus,

I commonly use a .004" stepover on 3-d carvings to get optimal detail. Yes, it takes a while, but not as long as you’d think if its not a huge piece. (A 5.5" x 7.6" work piece took 3.5 hrs)

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oh duh metric/imperial. Yeah 1/10th of a mm (0.004") is not TOO bad, I’ve done a pretty sizable heart that way (New (kinda): Going from STL to GCode directly (CAM)) recently… took a bit over 3 hours.

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I did some very shallow (maximal 0.25 mm depth) cuts with a 30° amanatools bit and they looked awful. After letting the bit go to the maximal depth (w.r.t. cutting width, which was like 0.5-1 mm) the cuts came out clean.
So I assume that the tip of a Vbit is not necessarily as sharp as the rest of the flutes…

And…it basically has a speed of zero, so the tip “scratches” the material as much as it cuts anything.

Well I guess that’s the actual relevant statement :smile:

I use engraving bits quite a bit, 30 degree or so, and they have a defined tip diameter. .002, .02 ect, whatever you decide to buy them in. I have a few V-Bits, but don’t use them much outside of locating points. I seem to recall them having a visible flat, albeit quite minimal. Still larger than my smallest engraving bits. If you step over accordingly, I suppose its not much different than a tapered micromill.

Fusion360 will create an 3d Adaptive toolpath if your tool is input at a chamfer mill with defined flat. Now it’s not going to look super pretty and you’ll have to run a smaller opt load and minimum cut radius than tip diameter/radius. Speeds and feeds adjusted for depth of cut, lubrication a plus.

The best bet would be to use 3d pocket with the chamfer mill selected and rest machine off of your previous roughing toolpaths. Small stepdowns.