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We will now interrupt the regularly scheduled programming for this good old blades micropod test. Surface grinders.

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Um what to say about surface grinding? So uh you'll probably experience this if you've uh spent any bit of time using your flat platen to uh flatten things that it's not very accurate. Now I've seen amazing things done on flat plattins in order to get uh pieces relatively flat, but you might find that there are certain inconsistencies in your flats that you only expose when you're doing hand lapping or you're doing finishing and uh you're adding certain embellishments like bolsters, uh for instance. Uh bolsters are really good uh a good indices of how not flat things are because when you have two flat mating surfaces that cannot be obstructed by epoxy or glues, uh you will see gaps, galore in it, and that's just the way it is. Now, uh there are some guards and bolsters and things like that that you can use silver solder on, and that helps to you know mask uh a deficiency in its flatness, but there's only so much lipstick you can put on a pig. And the reality is that lots of things in knife making are not flat and you got to make them flat. So uh it's uh very common with blacksmithing or bladesmithing that you have things that you're heating and beating and it's moving around and it's not flat and whatever, you know, like it's it's par for the course. But when you're doing stock removal and you have a flat billet and you do things to it that makes it inherently not flat, uh you're got you're you're basically taking something that is like mostly flat, turning it not flat, and then have to get it flat again. And that sort like that circle of um I don't know, inefficiency is something that a surface grinder helps to account for. Now, it used to be where the fixed surface grinder, whether it was manual or hydraulic, was the only option that we had available, but with the advent of the uh attachment uh surface grinder for like two by 72 grinders, uh, it really opens the door for a lot of ability to get things mostly flat without having to worry about uh you know getting a big bulky unit that you have to sit sit somewhere and worry about, you know, hydraulic fluid and coolants and you know stones and whatever. Um the one thing I will say about attachments, and it doesn't matter what kind of attachment it is, if it uses a belt and if it's an attachment, it's not going to be as accurate as the the less accurate surface grinders that are you know actual you know standing units, right? Um belts are inherently flexible, uh there is nothing you can do about it. They the wheels that you use on your on your uh 2x72 or with the attachments move around. The way that you address the uh work piece, so whatever you're trying to get flat um is going to distort things, and so by and large, you're always going to build a little bit of inaccuracy and lack of precision into using belts, uh using attachments, and uh that's just the way it goes. You you can get a lot closer uh with accuracy and precision on that than you can a flat plant, typically. Um, but if you have a if you have a unit that's running and you're using a stone and you compare that to any level of finish that you can get uh with a with a belt and an attachment or even a belt-driven surface grinder uh or like conversion, uh, it's not gonna be the same. Uh stones are inherently the most accurate surface grinder that you're going to get, and then the finish is going to be the best. Uh, I there are lots of people that will get um older surface grinder units and they'll want to convert them for belts or convert them to a belt attachment. But what I will tell you, the the reason why you would do that is thus you like understand that when you convert a surface grinder to a belt, you are making a high precision tool a less precision tool, but in doing so, you are adding some level of versatility to that machine that allows you to do other things. For instance, uh you can super glue a piece of metal onto the bottom side of handle handle material, and you can throw it on your magnetic truck on the surface grinder, and you can belt finish uh uh scale material and get it real flat. You can take a much thicker metal material than you were intending on using, and you can surface grind it to an approximate dimension on your surface grinder with a bell, and it's a lot easier. And the reason uh I mean you can tell this because uh if you use let's just say you take uh three thousandths off of a piece of metal, and then you try to do that same thing on a stone, uh you will find out very quickly how much a stone does not like the operation of taking big cuts off of steel. There's a lot of contact involved, the dressing gets knocked off, and the abrasive gets uh fractured on the stone, and if you don't fracture the stone to the point where it crumbles off and flings everywhere, uh you will make it groan. Uh sparks fly everywhere, it hates it. Um it's not really meant to take off you know humongous chunks of material at one time, it's meant to take off very, very small pieces and make uh of metal or material and make it very accurate. So uh you might be trading, you might be trading accuracy or precision, but you might be gaining versatility, and that's something to think about. But there should never be a dispute that you can get the same level of precision on a belt converted surface grinder that you can on a stone. It just doesn't exist. It is nonsense, and uh anybody who believes that really doesn't understand the fundamentals of uh you know geometry and abrasives when it comes to surface grinders, um yet I don't know. I I've heard it and seen it, and it's a it's a myth uh that really needs to be dispelled because it I think it's probably the self-conscious maker that says, well, they're the same thing, but they're really not, and and it's okay. It's okay to to convert a surface grinder to a belt, uh, a belt apparatus, and it is okay for it to not be as accurate because for me, if I were to do it, the versatility might work, it might actually be an advantage over precision where I can kind of do everything. But if you want to get to like half ten thousandths tolerance, if you can do that on a belt, I would be surprised. And anybody who can show me that you can get that accurate on a belt finish like that, um, I you know, please, please do anybody who can actually show that to me and mic it and tell tell me that it's more accurate, um, I will change my stance. But in the meantime, I know absolutely that I can get a half ten thousandths tolerance on a stone, and I have never been able to see any example of anybody do that on a belt. So let's do away with that. Understand that surface grinding uh by virtue is more accurate on a stone than it is on a belt, and that you really, you know, if you're doing conversion on it, uh just you're doing it for versatility and for the fact that you can get much higher tolerance than with an attachment um with a lower end attachment or just going off your your flat platinum. If we accept the fact that stones are the most accurate, we also have to accept the fact that you need a stone in order to remove material. Now, uh there's lots of different stones out there, and something that you have to remember about stones is the the abrasive construct or matrix uh really affects a lot of the type of finish that you get, how much you can take off at a time, um, and and how brittle the dressing will be on that specific stone. There's all sorts of different grit stones that you can put on your surface grinder. Uh, the ones that I've found are the most successful uh for me are uh I think it's Saint Saint Gobain, and they are produced in Mexico, and they're by Norton. And they have a very long shelf life. Uh, the one that I use is a 32 grit, and I will tell you, even though it is 32 grit uh matrix, uh, what I can achieve is a near-finished polish on my pieces if I am going uh with the correct feeds and speeds. Um I can make a thousandths to a thousandth and a half cuts on it for roughing, and then I can go back in and redress that stone and then go in for my final cuts where I'm taking maybe uh maybe a half thousandths or um you know two-tenths of a thousandths or something like that off at a time, maybe three-tenths. Um, whatever the case may be. You can take some material off to get down to your final dimensions, and you flip it over and do it on both sides and uh keep everything um even, and then do my final passes after dressing my stones. Um, there's lots of other abrasives out there that you can try. There's different abrasive matrices or matrix that you can try, and all of those uh affect your overall surface grinding finish, um, how how much you have to dress the stone. Um if you slow, if you slow the surface grinder down, both on your cross feed and your uh and your your table movement, you can preserve the leading edges uh on your stone for a longer where you don't have to dress it as often. But if you're taking deep cuts, it's just going to knock the dressing off of it. It fractures the stone unevenly, and then you're gonna have to redress it in order to get the precision you're looking for, because the stone is just cutting um it's cutting too depth for the portion of contact that it makes with that stone for a duration, but then if you're running uh the cut too heavy, then it will it will unevenly wear the stone and it might cause um it might cause uh material to bed inside of the stone and it affects the cut. Um if you run these things a lot, you'll see. Um the other thing is that uh I don't recommend running surface grinders with stones without coolant. Um, it makes a humongous amount of difference on not only the likelihood that your piece will warp because of heat buildup and because of the tension that gets caused whenever you're removing material from an already you know heat-treated product or something like that. Um, but it also preserves the tr the dressing of the stone, and that's probably the most important thing. Your endeavor in running a stone is to try to maintain the dressing for as long as possible without having to redress because you know it takes time and energy, and to decrease the effect that surface grinding has on a piece, uh, such as warping it. Uh, you have to be able to dress a stone and understand how that works. Um, I dress my stones fairly fast, so I'm I'm in the crossfeed, I'm running it pretty quickly across the stone because I'm looking to break up or fracture the surface uh and true it up across the entire face of that stone. Um, some some will run it really slow. Um, you can do things to burnish the surface so that way it presents at a higher grit than it really is. Um, but the idea at least being that you need to be able to dress a stone, you need to be able to dress it accurately, you need to be able to fracture the surface to get rid of any uh compounding um materials or anything like that that has uh you know burdened the stone, and then you need to be able to figure out uh what your speed and feeds are on your workpiece uh to get it right. And there it's an art. Like you could spend years perfecting a surface grinder um uh operation, and if you want very high precision, you gotta figure it out. Like the machine will do it for you, but you have to be able to finesse it because each surface grinder is different, the stones operate different, the magnetic chuck that you're using operates different if you're using one. Um, your uh you know, if you have slop in your in your uh in your down feed or anything like that, all those are handicaps that you have to work through. If you're getting a brand new surface grinder that's high precision and everything works great, um, you know, you you spend tens of thousands of dollars on that and it does everything you want it to, sure. But if you try one of these old machines, like I have a Boyer and Schultz uh hydraulic uh surface grinder from the 40s, I believe. It's like late 40 40s, early 50s, and it's uh it's a little finicky, but it produces high results. I can mic it at half ten thousandths, and it's it's good. I I've got to figure it out, but you have to do the same thing, and so there is a learning curve to every surface grinder that you get, unless you're buying a brand new one, and you're still going to have to learn the fundamentals like dressing, uh your speeds and feeds, and um and coolants and things like that. Like not everything is gonna you know work itself out for you. There's still a lot of trial and error involved with you know getting good at it. So, regardless of whether you're using a flat platen, you're hand lapping, you're going with a surface grinder attachment, you're using uh a belt on your surface grinder, you know, your stand uh standalone uh surface grinder, or you're using a stone, um there's many different ways to skin a cat, as they say, and each one has their merits and time and efficiency inside of your shop. But if you want to go for the creme de la creme, uh get get a stone surface grinder and learn how to use that tool because you can get high accurate results and it can make your fit and finish of your knives a lot better. But just remember it does take time to run it through that machine. So if you want high accuracy, you're gonna pay for a little bit on time uh and the learning curve to make sure you can get it that way. Hope this all helps.