Why Accuracy Matters in Woodworking - Common Mistakes to Avoid

all right let's go baby today i want to talk about accuracy and woodworking and why it matters and i'm going to tell you some mistakes to avoid so you can get accurate parts because it makes a big big difference when you're getting nice square equal parts compared to in fact let me show you why don't you come on into the bench i always like to say it's a quote from william ing good joinery is done with a pencil and great joinery is done with a marking knife now let me show you why that is now when you look at a pencil versus a marking knife now if you see this is a 0.05 millimeter mechanical pencil it's next to a marking gauge line they don't look that much different but i'm going to show you in a second why they are very different this is a standard number two pencil like this one here this is one of those fancy black wing pencils that somebody gave me which are super nice for rough joinery or for like breaking down lumber and then this is your standard carpenter's pencil and aside from the fact that the angle on wooden pencils or even some mechanical pencils will kind of push you away from your ruler a little bit they do have a thickness to them so when you look at a mechanical pencil .05 millimeters it's just about .025 inches which you can see that is 0.025 inches it's really not that big but where it becomes a problem is when you compound those errors i know all of us have put together a project you've clamped it up and then when you go on to the next step you realize it's just not quite square well here's a great example of why that is i'm going to put this graphic up here on the screen so let's say that you had parts that were milled down and you wanted to make a coffee table base that was 14 inches by 36 inches now if you drew that with a pencil which is .025 inches let's say each time you were cutting a piece you cut on the opposite side of the pencil so for one of the side pieces you cut on this side of the pencil line but you cut right up to it and then the next time you cut to the other side of the pencil but right on the other side of it and you did that four times you're going to have an error of 0.1 inches so it's a tenth of an inch now when you add that up and you put those parts together i just drew this in fusion so you could see you end up with an air rate of about .3 degrees over three feet that doesn't seem like a lot right but let's look what that actually looks like here is a bevel gauge i used this cmt digital angle finder to set this so when you hold that up to a square look how big of an error that is now when you stretch that line out over three feet 36 inches you're gonna have a tough time fitting a tabletop or a shelf that goes in between the legs because you're going to cut it square on your table saw but then when you go to fit it up it's not going to quite fit i know we've all had that experience but again that's not the end of the world you could make that work with some sandpaper or maybe a hand plane you could shave down one side at an angle maybe even use a track saw but that might be getting close with that small of an air but let's look at it for let's say you were making a three inch by eight inch jewelry box or maybe this is a drawer front you've got your drawers fit in and you have a nice square opening but then you make this error where you're off by .025 on each piece either plus or minus and that adds up to 0.1 that gives you an error of 1.3 degrees now check this out that is a massive error you would have to redo something that would be a wasted piece of wood because there's no way you could fit that lid in there or that drawer front and make it look good so this is why using a marking knife matters and it's not because the size is even that different but it's the the fact that you can feel it and you can set saw teeth right into it like um let me take my mic i don't know if you can hear that but it clicks right into place and now i have an exact reference area this works for other tools as well so i'm going to show you some of the tools i use for super accurate measurements and marking those on my pieces of wood and then i'm going to take you over to the tools and show you exactly how i set those tools up using those reference lines on my pieces okay so here's some of my most used marking instruments what is absolutely most important the things i carry in my apron at all times marking knife marking gauge and a center punch these four things are something we carry in the new cat's moses tool store which is kind of cool but to a lesser extent maybe uh dividers and a bevel gauge or calipers but you definitely need a good square you definitely need a good measuring tape this is a festival one i bought a couple years ago that i've come to hate and i think if i'm going to recommend anything to you don't get something with millimeters and inches on it or imperial and metric the other thing did you know that this little piece at the end of a tape measure it's designed to move to account for the thickness of the hook so when you push it it moves exactly the thickness of the hook and when you pull it it moves exactly the thickness of the hook so that way you can do inside and outside measurements sorry but i digress here let's talk about why these are important when you make a knife line you have an actual reference so when you make a knife line you have something you can actually feel your chisel slide into so you can get exactly in that line when you have a knife line like if i'm going to saw a piece by hand i'll make usually with a knife you want to go one nice kind of light stroke and then you can get in there a little bit deeper ladies gents knock it off and then you have a reference line that you can find and if you're using a hand saw what you can do is get a chisel and you can just make a little bit of a relief and watch this it's going to pop up exactly at your knife line so i now have a place that i can very easily rest my saw blade in and it's so easy to find and then it just rests right up against that knife line another thing you can use is a marking gauge now marking gauges are great i have a pretty stupidly large collection of these in fact i even have a video where you make your own i'll link that up here in your top right hand corner but a marking gauge does the same thing and i much prefer these wheel gauges because the bevel on the cutter will actually pull the fence into your wood but again you get that same reference line and with hand tools that's very very important if you're chiseling anything or hand sawing anything it's very very important to have that reference line but it's also really important when you go over to power tools which we're going to go do in a second i'm going to show you how i set all of these up dividers these are great because they leave an indentation you can find with your marking knife so same as a center punch anything that leaves a dent in the wood you can very easily find with your marking knife which you then can slide your square up to and make a line and look at that that is just dead dead center a good combo square is of course very very important you really when it comes to accuracy you want to buy once cry once on these things in fact my friends over at tools have a really good blem version this you can see this was a blem mita toyo that i got they're about half price of retail you can see they try to scratch out the name but they are so accurate for the price it's really incredible uh they also have these great double squares and these blem rulers and when flat rulers get really really helpful is when you're in the middle of a piece if you're trying to do a tenon or something and you've already marked your square line across a piece you can take your ruler and slide it right up into the line you can even if you want to be really accurate about it you can find the line with your marking knife because it has a reference and you can slide your ruler right up to it and now you know you're exactly on it and let's say i wanted a two inch mortise any good ruler that includes combo squares rulers they're going to have these etched into the metal so you can actually again find it i can actually slide my marking knife right into that mark so if i want to make a two inch mark i can just find it look i'm locked in there and then i can just transfer that to my wood and then take my square i know i'm exactly at two inches and make a mark alls and this jimmy diresta ice pick are very much the same as a center punch but they'll make a smaller line which may be something you don't want to do like a big spring-loaded thing these are great for drilling i'm going to show you that in a second over at the drill press why those are so important and dividers i use for dovetails so you can lock your piece in the vise and you can actually make a mark and then you rotate your divider over and then you get exact equal spaces and i think in my comprehensive guide to cutting dovetail videos again that will be linked right up here in the right hand corner i show you how to do that but what's great about making an impression like that is you can again slide your marking knife right into the hole you slide your square up and then you make your mark so these are some of the tools of course you know honorable mention digital calipers these make transferring measurements a breeze you know if i let's call this let's say this was like a a dado or something i wanted to transfer that outside measurement to something it'd be great i have a good video on these again linked in the corner but i always think digital calipers shouldn't be your first tool purchase but certainly down the road when you've got all these other things i would highly recommend a good set of digital calipers so let's go around to the tools in my shop and i'm going to show you why a cut line for a measurement matters on your tools and why it makes your life so much better okay so let's talk about the table saw another good little tip is always use the same tape measure for the whole project don't switch between tapes because tape measures can be a little bit off so as long as you're using the one that's the same amount off every time all your pieces will match but you just take your marking knife put it right at the 30 and now i have a place this isn't going to move i can even like slide my piece of wood here at the 30. take your square slide it up to the marking knife make a light mark make a thicker mark now here's what's great about this is let's say i needed to wrap this measurement around the whole thing let's say this was going to be a tenon and i needed a very accurate line that met again on the outside well that's really simple to do because you can take your square and you do the same thing you take your marking knife and you can feel that line look it's it's in there right now i can move my piece of wood and then you just slide your square up to it like that making sure the marking knife is flat against the ruler hold it like that and then you can just make your line and you can see they match up perfectly so then you just do the same thing all the way around and you're going to have a line that matches up perfectly so that's great for cross cuts but what about rip cuts well that's where your marking gauge comes in so your marking gauge you set to a certain distance and remember how i talked about all rulers should have indents for the measurements well the same thing works for this now this marking gauge is awesome this is my favorite one i've been using one just like this for years and years and years you can take it and put it in one of those lines and then with this one you can just micro adjust it right so you feel it click into that line and then lock it down other marking gauges like this other one from our site what i do is i just lightly tighten the screw so it's has some friction and you can do the same thing like if i wanted to set the one inch i just lock the knife in there at one inch and then give it a little tighten and there we go we can always be at one inch now then you just take it and a good little tip for these is intuitively want to hold it like this but i find it's a little bit easier to control if i hold it like this and push in and you want to do it again lightly and then you can come back and darken it up as you go but that is going to be for your rip cuts and i usually only do it on the very end of the board so i'll get my measurement and then i can just do it like this and then let me show you how i set up my saw okay so now all saw blades literally all of them with very few exceptions have teeth that go beyond the body of the blade and that is so the air can get in the cut and it can clear material so they stick out it's called tooth set they stick out further than the body and there's one that sticks out this way and then it alternates that way throughout the whole saw blade they go back and forth so when you actually have a cut you can feel when you're setting up your crosscut sled for a super accurate cut you can actually feel it click right in there so i can actually feel that now and i know that is going to remove exactly up to my line right there and that is how you get super accurate cuts with a knife now when you look at the marking gauge example for rip cut you can do the same thing and that's why i only do the front because i know my fence is square but you could actually do it along the whole top if you wanted to or if you were doing it by hand or using a hand plane you could do that and that way you get down to your line if you're planing from the top but you can do the same exact thing with the opposite teeth i have this tooth here i know that's going to be right in there so i can just slowly tap my saw over till i feel it kind of right in that line that is right in there lock down my fence give it a little check and we are right on that line and we're going to get a perfect cut so let's go over to the drill press and talk about drilling accurate holes all right so let's say you wanted to do you were drilling in a a round table leg and you wanted to go an inch and a half in from the corners so you want to do that really accurately so what you could do you set your square to an inch and a half and i'll just make a little line because we don't need to do a line across our whole piece i'll do the same thing here with my marking gauge and now i have a little x that i can find just like that and now i have an indent and i'm going to do one more over here just to show you another example of why this is so so helpful so we know the center of this hole here is the exact center of our hole so then what we could do is we use this is an inch and a quarter forstner bit we can use that to find our hole and you can like sort of wiggle the board and feel it move around and you know you're dead center there and then you can just drill that hole and there we go now we have a hole that's exactly an inch and a half in now here's another great thing about using a center punch for drilling holes obviously all drill bits have a center point whether it's a brad point or a conical shape or a forstner bit like this you're going to have a center point now that's great because you know if you're like me and you've got to draw a bunch of holes it'll help you find the hole now look i haven't lined this up at all i'm going to turn it on and then watch this and we're going to find that hole and right as it starts to enter the tip of the center punch i'm going to let go i'm going to loosen my hand you see it kind of wiggling around it's finding center and now it stopped wiggling i got pressure on it now and we're drilling exactly in the center of that center punch hole so a center punch or an awl or that ice pick i was showing you are all really really important for drilling holes accurately now let's go over to the router table and i'm going to show you how i do this with a router which is a little bit more difficult than a saw or a drill press but pretty much the same concept all right so let's say you wanted to do a mortise and a mortise needs to be pretty accurate so you know that it's going to be an inch in from either side use your marking gauge to create a line so you know where your mortise is you know your stock is nice and square and flat and so you can use these edges for reference but how do you know that your router bit is going to go right up exactly to that line well it's very simple because you have a cut line so i've brought my router bit down to the surface right by the edge i'm going to spin it i mean it's very obvious it's over the line right now but a router bit has an arc so i'm going to bring it to where it just is in that line and i can see that it's right there and then i'm going to spin it you usually want to go backwards so you're not marring up your surface too bad especially if you're over your line if you're in your waist it doesn't really matter but i'm going to get right to where i think the furthest point is and just give it a little spin and you can see just for a split second it crosses over that line so i'm just going to adjust my fence just a little bit and now i'm just perfectly right in that line so it's really really simple to do so now i know when i plunge down that i'm going to be right in my line the whole time and look what this is what's great about that marking gauge i come over here lock it down i'm in the exact same spot you don't have to worry about it so it's uh it's a really simple way of being extremely accurate and that way you know that you can transfer your measurements over to your tenon and they're going to be right let's head back over to the bench so accuracy matters guys remember that uh drawing i showed you from fusion it makes a big difference and it's not like you can't get by with something that's a little out of square it just makes your life so much easier when it is because you don't have to extra steps and you know one of the things i say all the time is the only difference between a beginner and an expert woodworker is the expert knows how to fix his mistakes we've all been there i still do it all the time i make mistakes use these techniques you have to fix a lot less things get done a lot faster and to me it's a lot more enjoyment if i'm not always chasing square and trying to make things fit so highly recommend you check out some of the tools i talked about over at the new cats moses tools store guys thank you for your support i the last week we launched the new company and just absolutely incredible i forgot to list the shirts so head over there we've got the brand new cat's moses tool shirts up there with the new logo on there and now my body suit has a wedgie um guys thanks for watching stay safe in the shop [Music]

Channel: Jonathan Katz-Moses

Views: 211,420

Keywords: woodworking, why accuracy matters, accuracy and precision, accuracy, woodworking accuracy, tools, wood, square, woodworking tools, woodworking tips, measuring, woodworking precision, table, saw, accuracy in woodwork, how to get accurate joints, how to get tight joints, furniture, woodwork precision, beginners woodwork, woodwork accuracy, hand tool woodworking, woodworking for beginners, katz-moses, katz moses

Id: LWUDlzm0VxU

Length: 17min 55sec (1075 seconds)

Published: Sun Oct 24 2021