End mill spiral bit for wood are they different than spiral bits for metal ?

Hello I am building a workbee cnc. I use a 800W spindle with an ER11 chuck.
So I choose to use 6mm bits.

I will cut aluminium, and hard woods (mainly bubinga and some ebony).

My bubinga pieces are around 45mm in thickness, contouring them is what leave me puzzled !
Do I need to buy a bit with at least 45mm cutting area ? Or can I use smaller bits with multiple passes?
Will the non-cutting area rub against the wood and create friction ?

Also I cut a lot of metal (mainly aluminium and stainless steel of 2mm),
can I just buy a 4flutes HRC60 bit and use it on bubinga wood ?

Because I read that wood bits use a different cutting ?radius/shapness? is it true.
I wanted to do everything with these bits : https://www.aliexpress.com/item/33042760122.html

Thank you for your help.
I watched a lot of videos but none explain these things.

Quote:

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Originally Posted by digiwood

Hello I am building a workbee cnc. I use a 800W spindle with an ER11 chuck.
So I choose to use 6mm bits.

I will cut aluminium, and hard woods (mainly bubinga and some ebony).

My bubinga pieces are around 45mm in thickness, contouring them is what leave me puzzled !
Do I need to buy a bit with at least 45mm cutting area ? Or can I use smaller bits with multiple passes?
Will the non-cutting area rub against the wood and create friction ?

[Yes, you'll need at least 45mm in flute length, unless the shaft size is smaller than the diameter at the flutes.]

Also I cut a lot of metal (mainly aluminium and stainless steel of 2mm),
can I just buy a 4flutes HRC60 bit and use it on bubinga wood ?

[You can use it, but a 2-flute bit would work better. 4-flute cutters are stiffer, and better for hard materials like steel, but 2-flute cutters evacuate chips better in materials like wood and aluminum.]

Because I read that wood bits use a different cutting ?radius/shapness? is it true.
I wanted to do everything with these bits : https://www.aliexpress.com/item/33042760122.html

[Those would be better for steel than for wood.]

Thank you for your help.
I watched a lot of videos but none explain these things.

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[If you're building a machine like this one: https://bulkman3d.com/product/wb/ , aluminum is the hardest material you can expect to cut with it (as they make clear in the text). Steel, and especially stainless, is not going to work very well at all. You'd need a milling machine for that, which resembles a router but is much stiffer, with a different sort of spindle. Buy 2-flute cutters; not 4-flute. ]

Quote:

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Originally Posted by awerby

[If you're building a machine like this one: https://bulkman3d.com/product/wb/ , aluminum is the hardest material you can expect to cut with it (as they make clear in the text). Steel, and especially stainless, is not going to work very well at all. You'd need a milling machine for that, which resembles a router but is much stiffer, with a different sort of spindle. Buy 2-flute cutters; not 4-flute. ]

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Oh, I did not know it was only for aluminium. Thank you for pointing it.
I will build one screw driven, but it's not from bulkman3D, I am building it from scratch with a Duet3D wifi 2 controller.

I only plan to cut 5mm (3/16 Inch) aluminium sheets, and 2mm (1/16 Inch) stainless steel sheet. I hope it will work good enough ;).
And bubinga wood blanks of 45mm (almost 2 inches).


Thank you for recommending 2 flutes spiral bits for wood cutting.
But should I buy a end mill bit with 2 inches of CUTTING LENGHT ? Since my wood is almost 2 inches ?
Or can I do it with endmills of less cutting area but with 2 or 3 passes of cutting ?
Will the non cutting area of the shaft rub against the wood ? on the second pass.

Thank you.

You are NOT going to be able to cut stainless steel with a router. No chance.

On a lightweight machine like the WorkBee, you're also going to struggle cutting 45mm Bubunga. You'll need to take many light passes, maybe 5mm/pass.
In some cases, you can use a bit with a shorter flute length. Sometimes the shank rubbing can cause burning, sometimes it won't. Depends on the quality of the bit, and whether the flutes are exactly the size of the shank, or smaller. Ideally, you want the flutes to be at least as long as the cut depth.

And yes the geometry is different between metal and wood cutting bits. But metal bits will still cut wood. You'll just have to try and see what results you get.

OK thank you guys !
So I can cut wood well enough with metal bits, but the geometry of metal bits is not the most "efficient" with wood. Ok.
I am a minimalist and like to have to lowest amount of tool.

So can you recommend me one 6mm (or 1/4") bit to to cut everything I need ?
I mean the best geometry for hard wood and aluminium.

I will definitely use many light passes, thank you for the recommendation.

Hello Digi - You will end up with many tools. I don't find using a helix tool good for wood. Use straight cut bits. By "contouring" do you mean outside profiling? contouring usually means some sort of 3D cut. For contouring you will need rounded tools such as veining or half round... Peter

Thank you, and sorry for my bad wording I meant creating a cut around the blank.
Not like 3D contouring but more like cutting the outside shape of the finished piece.

For creating 3D edges I will use a 6mm ball end 2 flutes.

I will buy 1 4flutes for metal and 1 2flutes for wood and 1 straight bit cutting the edges. I will try to find something on aliexpress, because I want to buy cheap to start then upgrade to something better later. Does it seems ok ?