Bit Rotation

[plumlost]

Hello, will be purchasing AR8Pro shortly. While making a list of bits to purchase, I noticed some are right rotation and some are left rotation. Which rotation do I need for the AR8Pro? Thanks in advance for your advice.

[arsystems]

Could be wrong but I think the spindle only spins one way? Clockwise... The bit type may have to do with climb vs conventional milling as well? Some of the pros on here I'm sure will chime in with more info.

[gerry]

The bit spins clockwise. A conventional bit (right hand), will pull the work upward. The good news, is that it will clear the chips fastest, thus run cooler. The bad news is that it also pulls up on the top edge of the cut, tending to chip out more. A downcut bit (left hand), pushes things down, compacting the chips in the cut. This can be a problem, though not bad. Correct feeds and speeds will correct most of this problem with overheating the bit. The up side is that the top of the cut is extremely nice, the surface edge is pushed down. Very little chipout on the bottom, since the cut is supported by the table. Good and bad for both. Read up on 'upcut' and 'downcut'.

Here's a list I suggest:

.125" Mill
.125" Ball Nose

.25" Mill
.25" Downcut Mill
.25" Ball Nose

.5" Mill
.5" Downcut Mill, if you feel rich
.5" Ball Nose

60 Degree V Bit
90 Degree V Bit

1.5 Surfacing Bit. Wasteboard flattening and planing wood for flatness.

Get something like Onsrud bits, they're good and not too expensive. You can add to your set as the need arises. This basic set will get you through most projects.

[alwz4gbp]

Gerry, Would that mean you would not recommend the 8 bit starter set that they have when you build your machine on the site? I'm gonna be ordering within the next week or so and was planning on getting that.

[gerry]

Amana bits are great. There is nothing wrong with the 8 bit set. They're including more for 3D carving than my suggestion. Purely a personal suggestion. Add a couple tapered ball nose to mine, and you got it. Or, add the 0.5" ball and plunge bits to their set. If you're playing with Vcarve, test a .5 bit in the design as 'use larger area clearance tool' bit for for hogging out material and you will be amazed at the time saving over just .25 bits. Once you get going, you will quickly find out what you're missing.   

The main thing is to get in there and do some carving. Your selection of bits is more defined by the way you work and design. Have fun.

[Deleted]

To answer this question correctly and not have you buying the wrong bits we need to know what you plan on doing with your machine and what kind of materials you plan on machining. Bits for aluminum, plastic, and wood have different geometries although generally speaking, you'll be getting one and two flute bits and coatings aren't necessary as the flashpoint of all but the metals are well below where the coatings function. Urethane foam is pretty forgiving so bits for anything else will probably work. V-carve bits for making signs aren't really useful for cutting 3-D designs where you need the round tip of a tapered or straight ball end mill. A large surfacing bit (1"+) is always useful for flattening your spoil board. There are some bits that can be used in many situations but the most important thing is to not get too many flutes thinking it will go faster or leave a better finish, the opposite is actually true. These machines can't feed fast enough or the spindles go slow enough, with enough torque or HP in general, to utilize more than one or two flutes in most cases. So let us know your materials and projects and we can keep you from buying nice bits that you won't use.

[james]

In my opinion there is not a one size answer here. You will find that you will acquire several bits because you will need them for different jobs but you will discover that there are bits that you use more. If your playing with wood and doing 2d and 3d signs, this is what I personally use, right or wrong.

I have an Amana 1.5" surfacing bit.

Freud #87-108 8-Piece Signmaking CNC Router Bit Set. This has some 1/2 shanks.

Freud 1/4 up spiral, down spiral, and compression. Ball and end mill

1/8 Ball and end mill

1/16 detail and 1/32 detail.

1/2" X 4" Freud straight bit for thick material.

Cheapy's. 

I know I'm going to catch some flack about this...but here it goes. Buy some ER20 collets from Amazon and buy some cheap metric bits. You will break bits. With trying new things comes learning experiences. New material, learning speeds and feeds of different material's. You will burn or break bits. Its better to learn on a cheap bit from Amazon that cuts fairly well but doesn't last forever at a price of $1.50 or $3.00. I used the metric equivalent of the 1/8 bit to cut the carcass, drawers, dovetails of a 2X3 plywood cabinet for my cnc accessories. That one bit lasted the whole project, it was still sharp at the end of that project but didn't hold up to much more than that. They are good for rough projects. If you break a bit, it doesn't hit the wallet as hard as a $20+ Amana bit. Cheap is not the answer to everything, but while learning, use a cheapo. I use my cheap bits on soft woods and plywood's. YES you get what you pay for, the more expensive bits will last longer, generally you can use a higher feed rate and cut cleaner. Yes, I do use my more expensive bits. 

I have a mix of decent branded bits and cheap bits. Its not critical right now, but once you learn what bits you gravitate towards when doing projects, get two or three of them on hand. If you are in the middle of a project and you break or dull your only bit, you are out of luck. I keep three of my 1/4 up spiral bits and two on my V-bits. The cheap bits usually comes in a box of 10. If I break one, I have spare and I immediately order another one that day.

Hope that this helps