I have been designing some bits and pieces ready for when I get my milling machine and Ive thought of a few questions so I thought I would post here in the hope of some expert advice :)

I know I need tungsten carbide bits, but how many flutes do I need? A Uk based supplier of tools sells 2, 3 and 4 flute bits, all the same price.

Why would I need a 2 flute tool over a 4 flute tool and what is the difference between them?

Cheers,
Tom

Tom,

The difference between them is 4-2 = 2 :D

A 2 flute tool may have more chip clearing space, especially important in gummy materials. Depending on what kind of a tool it is, it may also have center cutting (ie., drilling into solid) capabilities that are better in 2 flute than in 4 flute. This is also because of chip clearing ability.

4 flute is designed to allow you to increase your feedrate, since the chip thickness per tooth is relatively independent of the number of teeth on the tool.

Hey Hu, can you use 4 flute EMs on aluminum? I usually see the 2 flute guys being used and I notice that all of the aluminum EMs advertised are 2-3 flute, but if I could move faster that would be nice. Does a 4 flute give a finish on aluminum? Don't know why I never tried one.

I used a 3 flute EM once but it was a long 1/4 " one that chattered so bad I never tried it again. Prob. just did not have the feeds / speeds right.

ToMMy2000 and Dave I have used 4 flute with great success on finish cuts in aluminum and lost of flood, I flood everything :D

The only problem I see is that there is no problem if you keep the chips out of the way.

Dave,

I'd agree with Ken. Ward at WMS even uses a 6 flute high helix for aluminum. I think that high helix is important for aluminum cutting, to get the chips coming up quickly, so the cutter won't clog up.

So let me get this right:

fewer flutes = larger chips and a greater chip clearing capacity
more flutes = smaller chips *perhaps better finish* faster feedrate

Ok one last thing, the website I may buy my tools from just lists the cutter as carbide milling cutters, no mention of what material they work on...I am assuming you can use a carbide on any material its just a case of how long it will stay sharp for and the different properties it has such as flutes and helix will determine the material.

Cheers,
Tom

Tom, I get all my cutters from www.carbmax.co.uk although they only sell to the trade.
Their website is still under construction, but you can phone them on 0800 731 2724 and request a catalogue - of course, you may have to make up a phoney business name if you don't already have one! They really do have a great selection of cutters, with a good explanation on their use.

Excellent!

Ill give them a ring.

Thanks for the info :)

Cheers,
Tom

*Update - Catalog on the way :)*

I typically use 4 flute cutters for almost everything because thats what I have, but at work we use a lot of 4 flute cutters for steel and stainless, depending on the aluminum jobs but the main aluminum job we do we use a 3 flute 1/2" coated carbide that we run at 60 or 80ipm and a 4 flute 1/4" em that we run at 40ipm at .25" depth It leaves a really nice finish. this is all at 6500rpm. At these speeds and depths we are at the edge of breaking things;)
theres one of these 1/2" 3 flute carbides laying around that aluminum is completely melted to, musta forgot coolant;)

as my boss always says, "push it till it breaks, then back off a little." :D

Jon

@Tom: You don't say what machine. Carbide cutters demand a stable and powerful machine. Any chatter at all, and the edge will be gone. Look at it in a microscope and you'll see it looks like it have been tossed in a box with other cuttes and rattled about. Tiny chips knocked off it all along the edges. Carbide is very brittle. It's wear out time can be counted in seconds if your mill have resonances.

Do you have the spindle RPM, feed and stability to benefit from carbide?
Not to speak of guts. Most of my clubmates almost needs a gun to their head to use the cutters as cutting tools and not rubbing tools. Use it right, use flood coolant and one HSS cutter can cut you many buckets of aluminum swarf before it needs sharpening. Not in anodized though.

Its going to be a bridgeport clone, and will run about 3500rpm on the spindle.

Cheers,
Tom

OK. Bridgeport is quite stable. If it's a "good clone" you should be fine. And 3500 RPM should bring you in the ballpark for large diameter cutters.

But be aware of clamping not being rigid enough. I shred a cutter using a cheap swiveling vice. I could hear it, but it was too late. One carbide cutter scrapped. :(