Hey y'all. In this video I'm going to address an issue that I get a lot of questions on... ...and that is... ...for the beginning CNCer... ...what would be a good selection of bits to have... ...to see me through the majority of the projects I'm going to try to take on? So, we're gonna talk about bits in this video... ...what I consider to be a good selection of bits to have. Again, these are just my opinions. Let me qualify this by saying that I'm talking in this video about bits for wood. I mean soft woods, hardwoods, sheet goods like plywood, MDF, HDF, MDO board - things like that. I'm not talking about metals at all. And I'm not talking about engraving or cutting plastics or acrylic... ...foam; be it urethane or polystyrene... I'm talking strictly about wood and wood products in this video. So to get started, as a general rule, 2-flute bits or what you want to look at. You'll want to avoid 3-flute and 4-flute bits if it's at all possible. Those are made for metals and other materials. 2-flute bits, in some case single flute bits, are the best choice for wood. All of the bits I'm going to show you in this video are 2-flute bits... ...so that's what I'm going to concentrate on. There are going to be beaucoup links in the description box below. Some of them are to the bits I'm going to show you... ...others are to alternatives to those bits... ...so that you can get an idea as to what's out there and in what kind of price range to look for. On that subject, I am NOT going to recommend the more expensive, pricier bits. I know some of the more experienced CNCers are very brand loyal... ...and names pop up all the time. I'm going to stay away from those pricier bits for a starter kit... ...simply because the beginning CNCer... ...is going to be learning the machine and doing a lot of experimenting. And to me, just my opinion, it doesn't make a lot of sense to ruin a $40 bit... ...on the first couple of attempts to run a piece of g-code. I'm not going to recommend the super cheap bits... ...and I'm not going to recommend the more pricey bits. I'm talking about good quality bits that are in the center price range... ...that will see you through most of the projects the beginning CNCer will want to take on. I've only been into CNC for a little bit less
than five years now... ...but I've been a woodworker for getting close to fifty... ...and one thing I was taught at a very early age is to start with the basics... ...and then purchase tools as you need them. So I'm going to recommend four categories of bits that the CNCer should have on hand... ...to get through most every project you'd want to take on as a beginner. Then you can build up from there. You can purchase different angles of V bits, you can purchase smaller or larger ball noses from there. But the bits I'm going to recommend should see you through just about anything you'd want to attempt to cut. So that's enough of the talking head... Let's go ahead and zoom in, take a look at a few bits, and we'll look at my recommendations. Before we get into talking about the bits themselves... ...let's take a couple of seconds to talk about the collets. I have here, the three collets that I use on my Porter Cable 890 series router that I have mounted in my CNC. The router came with this collet made for bits with a 1/2 inch shank diameter... ...and this collet made for bits with a 1/4 inch shank diameter. And then I purchased from Elaire Corporation... ...and I'll put a link in the description box
below... I purchased this collet which is made for bits with a 1/8 inch shank diameter. Elaire sells collets of various sizes... ...for most of the popular routers out there - Porter Cable, DeWalt... ...Bosch, Milwaukee, and several others. I'll leave a link in the description to Elaire Corporation where you can check through and maybe find... ...a collet that will hold different sized bits that'll fit your router. The reason I'm bringing up the collets is because the first thing you need to do... ...is make sure of what size collet your router or spindle uses. If you only have a 1/4 inch collet, which is the most popular size... ...then you're going to be limited to using bits with a 1/4 inch shank diameter. Now, you can get reducer bushings... ...that will allow you to run a 1/8 inch shank diameter bit in your 1/4 inch collet. I've never been a fan of those. It's just my personal opinion. A lot of people use them, and they like them a lot. It's just my personal opinion. Your mileage may vary. The important takeaway from this is... ...make sure you know which size call it you
have for your router or spindle. The first category of bit we're going to discuss is the straight cutter or spiral cutter... ...also known as an end mill. I have here a carbide tipped straight bit. They're also known as mortising bits. These are standard router bits that are available at your local big box store... ...or you can order them online. Here we have an upcut spiral straight mortising bit... ...and a downcut spiral straight mortising bit. As I alluded to in my video on climb cutting vs conventional cutting... ...the way you can tell the difference between the up cut and the down cut is... ...if you look at the spiral... ...the cutting edge on the up cut bit is on the top edge of the spiral. Conversely, on the down cut bit... ...the cutting edge is on the bottom edge of the spiral. If you'll notice... ...the spiral also wraps around the center of the bit in a different direction. On the upcut, it wraps around clockwise. On the down cut, it wraps around counterclockwise. That can be a little confusing at first... ...so I say the easier way to visually identify what kind of bit you're looking at... ...is remember that on the upcut bit, the cutting surface is on the top edge of the spiral... ...and on the down cut bit, the cutting edge is on the bottom surface of the spiral. There are a few things to pay attention to when you're deciding on which bit to buy. First and foremost is the shank diameter. You'll need to make sure that it will fit in the collet you have for your router. Second is overall length. How long is the bit? Will it be able to reach down into the material as far as you want it to go? Third is the cutting length. On all 3 of these bits, the cutting length is 1 inch. Since the overwhelming majority of the material I cut is 4/4 stock... ...meaning the finished thickness is somewhere around 3/4 of an inch... ...this 1 inch cutting length gives me plenty of cutting depth to cut all the way through the material. If I were cutting into 6/4 stock -
i.e. a 2x6 or a 2x8... ...none of these bits would be able to cut all the way through... ...because the cutting edge is not long enough to reach all the way through the material. So that's something to pay attention to - the cutting length of the bit. The next thing to pay attention to is the cutting diameter. Just because the bit has a 1/4 inch diameter shank... ...doesn't mean that the cutter cuts a 1/4 inch diameter. You can get bits that have a 1/8 inch cutting diameter with a quarter inch shank. You can get bits with a 3/4 inch cutting diameter with a quarter inch shank. So pay attention to the cutting diameter, the cutting length... ...the overall length and the shank diameter. Another thing to pay attention to is the style of the tip. Both this upcut bit and this down cut bit... ...are straight mortising bits. They are designed to be plunged straight into the material. This straight bit, however, is not designed to be plunged straight into the material. If you look at the tip of the bit... ...the cutting surface of these carbide tips do not go all the way across the bit. There's a slight gap in the center. That means if this bit were to plunge into the material straight down... ...the center of that hole it's making is not going to be cut. That can lead to burning... ...depending upon the diameter of the bit, the material, and how fast you're going... ...it can also break a cutting edge or break the bit itself. The way to use this, if you're going to use it to cut a profile... ...would be to ramp in the plunge moves so it doesn't attempt to plunge straight down. Instead, it would move in this direction as it plunges... ...so that the leading edge of the bit... ...cuts away the material, so there's nothing there... ...when that center gap gets down into the cut. Do not attempt to drill holes straight down... ...with a straight bit that does not have a cutter all the way across the bottom. ...or with a down cut bit. Just to be clear on this; what I'm talking about is drilling a hole straight down. I'm not talking about spiraling in like such. I'm talking about plunging straight down. Do not use a down cut bit... ...do not use a straight bit that doesn't have a cutter that goes all the way across. Use an up cut bit - always. The reason is with a down cut bit... ...forcing those chips and the dust down into the hole when you're plunging straight down like that... ...the chips have nowhere to go. They're going to sit there and grind against one another as this bit spins. That's going to create friction. That's going to start a fire. It will start a fire. I know this personally. I did it. I don't know a fellow who knows a guy... I did it myself. The bit plunged in, those chips had nowhere to go... ...and when the bit pulled up out of the 3/4 inch plywood I was cutting... ...glowing, burning embers fell off of that bit. I had to hit emergency stop, move everything out of the way... ...took my material off, and I had a big black charred spot on my spoilboard that was burning. I dumped a bunch of water on everything, put the fire out... ...and everything was good. But it ruined my spoilboard, ruined my project; I had to start over. Simple rule to remember: upcut bit when drilling straight down. And it doesn't matter if your peck drilling or drilling all the way through. I was Peck drilling. It doesn't matter. Use an up cut bit to drill straight into the material - always. The next category of bit I'm going to get into is a surfacing bit. This is not really a surfacing bit. This is technically a straight mortising bit just like the others that I showed earlier. But I use it as a surfacing bit. It's a 1/4 inch shank 1.25 inch diameter straight mortising bit. And you can see the carbide tips on this bit, again, do not go all the way across the bottom. There is a section here, where there is no cutter. This bit is used to surface my spoil board or surface rough stock. The thing to remember about a bit like this is when there's no cutter all the way across the center... ...the plunge moves have to be ramped in... ...so it doesn't attempt to plunge straight down into the material... ...and bottom out against this section here where there's no cutter. Again, you would want to ramp the plunge moves in at least double the diameter of
this bit. In my case, this being 1 1/4 inches, 2 1/2 inches would be the distance I ramped in my plunge moves. You can get what's known as a bottom cleaning mortising bit. These have a cutting edge that go all the way across the bottom. It is split in half... ...one will be facing one direction, one will be facing the other direction... ...but it does have a cutter all the way across the bottom. Those you do not have to ramp in the
plunge moves. I still would, just to make it easier on the bit... ...but it's not mandatory as it is on a bit like this... ...where the cutter edge does not go all the way across the bottom. The things to look for on a bit like this is
the shank diameter... ...the cutting depth... ...and the cutting diameter. The next category of bits we're going to discuss are V bits. This is where you can get into trouble and spend a lot of money that you don't need to spend. ...and I'm a good illustration of that. Here we have a carbide tipped 90 degree V bit. Here we have a carbide tipped 60 degree V bit... ...and here I have a solid carbide 30 degree V bit. When I first got my CNC, I wanted to try to cover every contingency... ...that I could possibly ever run into when it came to v-carving. Then I got to actually working with the CNC... ...and I discovered I did not need this 30 degree V bit. You can see I've never had it chucked in the router. I think I may have put it in there once just to see what it looked like but I've never cut anything with this. I just don't need it. And again, I learned a long time ago to buy the basics... ...and then accessorize and expand as you need the tool. I just didn't take my own advice. About 85 to 90% of the cutting I do with a V bit... ...I do with the 90 degree V bit. That's my "go to." The remaining 10 to 15% of the V carving I do is done with the 60 degree V bit. I just don't do anything that small - your mileage may vary. The things to look for when you're buying a V bit are, again, the shank diameter... ...the cutting diameter which is the measurement from this edge of the cutter... ...to this edge of the cutter... ...the angle of the cutter... ...this is from this edge of the cutter down to the point and then back up to that edge of the cutter. On this bit, that angle is 90 degrees. On this one it's 60 degrees. Some software, when you input a bit into your tool database... ...they want just one single angle from the tip to the edge of the cutter. In the Vectric software I use, they want the total angle... ...from this edge to the tip back to this edge. In this case, it would be 90 degrees. Check with your software and see what measurement they want. On this bit, if they only want half of the cutter... ...it would obviously be 45 degrees. This one would be 30. In the Vectric software, they want the total angle. The other thing to pay attention to is the depth of cut... ...because, again, if the bit can't cut deep enough into the material... ...it's probably not the appropriate bit for the design you're attempting to cut. Again, shank diameter... ...cutting diameter... ...cutting depth... ...and the angle. The final bit category we're going to talk about is the ballnose end mill. Here is another area where you can really get into trouble and spend a lot of money you don't need to spend Here I have a 1/4 inch ballnose end mill... ...a 1/8 inch ballnose end mill... ...a 1/16 inch ballnose end mill... ...and a 3/64 inch ballnose end mill. I have never used the 3/64 inch ballnose... ...so I could have saved my money on that one. They're not outrageously expensive, but there's no sense spending money until you need the tool. The things to pay attention to when we're talking about a ballnose end mill are... ...again, the shank diameter... ...the cutting length... ...the cutting diameter... ...and the tip radius. The tip radius being from the center of the
bit... ...the radius of the bottom cutting edge. These are used in 3D carving. You would run the 3D roughing toolpath with the larger ballnose... ...then go in and do your finishing toolpath with the smaller ballnose. Without getting into the 3D carving discussion... ...let's think about this, because everybody wants to get as much detail as they can. ...and that's great... ...however, let's think about machining time. The normal clearance pass stepover on any of these ballnose bits... ...is about 20 - 25%. Meaning, when the ballnose gets finished carving a pass... ... it will step over 20 - 25% of its cutting diameter... ...then make the next pass. When you start your finishing toolpath... ...the normal step over on a finishing toolpath... ...is 10% or less. I've seen people use anywhere from 8 to 10%. I generally run 8 or 9% myself, depending upon the project. So if you have a ballnose cutter with a 1/16 inch tip like this one here... ...figure eight to ten percent of 1/16 inch... ...that stepover is minute. It's very very small. This is how we end up with 5, 6, 12, 18, 24, hour machining times. If you're trying to carve a 12 inch by 12 inch project... ...with a 1/16 inch ballnose, with your step over of eight percent... ...don't just bring a lunch - bring dinner
and breakfast. You are going to have a long, long machining time. So you've got to find the balance between efficient cutting... ...and the level of detail you really need. The things to pay attention to when looking for a ballnose... ...are the shank diameter... ...the cutting diameter... ...the cutting length... ...and the tip radius. So, summing up... ...these are the bits that I would suggest for the CNC beginner... ...who wants to do most general CNC work. That would be either the straight mortising bit... ...or the upcut and down cut spirals... ...the choice is yours. If I were to break it down even further, I would suggest just an upcut spiral
and a down cut spiral. I would also suggest a surfacing bit. In fact, that would probably be the first bit you chuck in your router... ...to surface your spoilboard to make sure it's nice and flat after you finished building or assembling your CNC. I would then suggest the 90 degree and the 60 degree V bits. Those should get you through most of the V carving you'll ever want to do. I would then also suggest a 1/4 inch ballnose and an 1/8 inch ballnose. Those should get you through most of the 3D carving that you'll want to do when you're just starting out. Just keep in mind the things that we talked about as far as shank diameter... ...cutting length, cutting diameter... ...in the case of the V bits, the angle of the bit... ...and in the case of the ballnose, the tip radius. So those are my suggestions for a beginner CNC "starter kit" if you will. Again, there are a bunch of links in the description box below... ...to all of the bits that I showed you here... ...as well as some alternatives to those bits, so that you can gauge for yourself... ...some of the prices and availability of the bits that are out there on the market. Again, I've gone for bits that are of good quality... ...but don't have an extravagant
price. ...and I've avoided the el cheapo bits while I was in the process. You may have ideas for other bits that you might need, and that's great. But again, these bits should see you through just about any project you'd want to take on as a beginner. Disagree? Let me know in the comments
below. If you have any questions or any comments... ...as always, feel free to leave 'em down in the comment section. If you'd rather not leave a public comment, head over here to my website... marklindsaycnc.com... ...then click this Contact Us link. I read every message I get through marklindsaycnc.com... ...and I do my best to respond to each and every one of them. marklindsaycnc.com is sponsored by Harneal Media. The web design and web hosting company that specializes in websites... ...for makers and the maker community. Harneal Media and I are both proud members of the Makers Media Network. Well I hope you got something out of this video. If you did, please click that thumbs up button down below. If you'd like to follow along with my beginning CNC series or any of my other CNC adventures... ...I do hope you click that subscribe button... ...and then click that little Bell button right next to it. That way you'll get a notification the next time I post a video. If you know somebody who might benefit from watching this video... ...I hope you'll share it on Facebook, or Instagram, or Twitter... Heck, share it on all three. I do appreciate
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