After I did my videos on X-Carve Vs Shapeoko (although now I use a Onefinity CNC) (Ultimate X-Carve Vs. Shapeoko Part 1 of 3 ) I get asked a lot what kind of bits to buy and what they do. I thought it would be best to write up a full post with links to my favorite bits as a constant reference for users searching for the best bits.
I’ll start off with the links to the bits I recommend (click the description to purchase):
1/4 down cut
1/8 down cut
1/16 down cut
1/8 compression bit
1/16 Ball Nose
1/8 Ball Nose
1/4 Ball Nose
30 v bit
60 v bit
90 v bit
Alternate Surfacing Bit
What do the different bits do?
A down cut bit is a flat ended bit that pushes the chips down toward the bottom of the work piece. This will produce a smooth upper (facing up) surface on the work piece. This is a great choice for wood material.
An up-cut bits is the opposite of a down cut bit where it raises the chips upward to the top of the work piece. This allows for faster cuts (as it's not ‘re-cuting’ ejected material) and a smooth bottom surface of the work piece. These work well with plastics and metals as the ejected material is not being recut and fusing to the material.
A compression bit is the best of both worlds. It has an up cut tip with a down cut shaft producing a smooth bottom and to surface. It is designed to cut full depth of pass and will speed up cutting out shapes. I use these on the majority of my signs (see example here: Compression bit sign cut out )
A V bit (or vee bit) is used for engraving. They are pointed like a letter V. They are used to get highly detailed, intricate designs while carving. These are generally used for logos, letters, and pictures. Different degrees offer greater detail.
Surfacing bits are really big and intimidating. They are used to flatten material. Generally, once you set up your CNC machine you want to use a surfacing bit to flatten your waste board to the spindle. These remove A LOT of material at one time and produce a lot of dust. Another great use of a surfacing bit is to flatten slabs of wood. This can take place of a router sled and planer (although a planer is much faster).
Finally, there are ball nose bits. If you ever want to do any 3D cutting these are the bits you will use. A ball nose is exactly that. Instead of having a flat end, the end will be rounded at the tip like a ball. 3D cutting requires special software that usually comes with a bigger price tag. These will be used once you become more familiar with your machine.
Why do end mills come in different sizes? Generally, you want to use the biggest bit you can while cutting. The bigger the bit, the faster you can run the machine, the quicker your project will finish. The design your cutting limits what size you can use. Greater (and smaller) detail will require smaller sized bits. Some CAD programs allow you to do a ‘roughing’ pass and a ‘finishing pass’. A roughing pass will cut using a large bit and require a finishing pass with a smaller bit to allow the fine detail to be cut out. This process will be MUCH faster than cutting the whole project with a smaller bit alone. This process will come with time.
Feel free to leave a comment or message me on Instagram Myers Woodshop Instagram or Facebook Myers Woodshop Facebook for any help! Happy Cutting!
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