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Author Topic: Ballnose Bits  (Read 1839 times)

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Ballnose Bits
« on: March 10, 2015, 03:03:03 PM »
Hey guys!!

I wanted to get everyone's opinion on ballnose end mills for wood. Traditionally I have always used general purpose uncoated cutters for finishing. Mainly because I have been in the tool die field for years and had an abundance. Most of the time finish was acceptable with a light touch of sanding. I find myself getting into more intricate work these days where sanding the geometry is not so easy. After a slough of different sanding equipment I've decided it's time to bite the bullet and get some cutters more specialized for my application. I've purchased some onsrud roughers and a few other brands. So far I've been pleased, but I haven't tried any of the ball nose. I wanted to get your guys thoughts as wood working has its demons as well. Mainly I cut a multitude of different hardwoods and epoxy laminated wood. Spindle speed and feed rates won't be a problem even with chip load being high on some cutters. I'm looking for different brands to compare by as well as personal experience from different people.  I use from a 1/16 to 1/2 ballnose depending on the work.  Most of the time I try to get my cut direction and wood grain in the proper orientation, but sometimes it almost impossible. I'm aware that the woodworking bits have a much more aggressive rake that wood brake in metal cutting. Any advice or recommendations would be appreciated. As always thanks for the help

Offline ger21

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Re: Ballnose Bits
« Reply #1 on: March 10, 2015, 03:37:23 PM »

The best way to minimize sanding is to use a small stepover, which unfortunately means more machine time. But more machine time is better than sanding, imo.

For large tools, 2 fluted carbide tipped core box bits work well, are cheap, and can be had in large sizes. For small bits, I use Drillman1 on Ebay. $3-$5 per tool, and they work great.

Honestly, it's hard to go wrong with ballnose bits in wood. Just try to stick to 2 flutes.
Gerry

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Re: Ballnose Bits
« Reply #2 on: March 10, 2015, 05:22:59 PM »
Thanks

Offline JTW

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Re: Ballnose Bits
« Reply #3 on: March 18, 2015, 07:00:29 PM »
I used to work for a company that made cutters for wood working machines. You need sharper cutters than for metal, although some hardwoods need metal cutting tools! Ball noses are great for 3D profiling, and MachIII is perfect for the job too, our older machines have to be drip fed for the much longer programs that don't fit in memory, Ger21 is right, use 2 flutes and as small a stepover as possible. We rough with a straight ripper, semi finish with a 12mm ball nose and then use a 4mm or even 2mm for fine details. If you want precision then sanding should be minimised. Let your machine do the work. If your camware has a remachining option to save time with smaller tools, use it!
Re: Ballnose Bits
« Reply #4 on: March 18, 2015, 07:32:12 PM »
A few years ago I ran into a buddy that worked for Fadal and he was demonstrating a machine at a show cutting a 3D aluminum part held in a 4th axis with 4 parts in four vices.  As I watched it run I told him I could cut it faster and and get a better finish too.  What I told him to do was to take advantage of the 4th axis and the cam program and set up cutting the 3D surfaces with the part tilted so that the ball mill never cuts right on center if possible. That way you don't do any rubbing and always have a good chip load.
Re: Ballnose Bits
« Reply #5 on: March 18, 2015, 10:51:26 PM »
Thanks for the input guys!!!!