Dovetails Ratios – Which one to use?

hi i'm rob cos and welcome to my shop we often talk about dovetail ratios without actually explaining it what i'm going to do is take you through the process of deciding what ratio is best for your dovetails i'm rob cosman and welcome to my shop we make it our job to help you take your woodworking to the next level if you're new to our channel be sure to subscribe turn on that notification bell and don't forget to turn on the notification on your mobile device so you'll know every time we release a new video good all right back to the bench what we're going to talk about is what angle i think your dovetails should be at least i'm going to give you some food for thought and when we talk about that we're talking about the angle of the tail in this case the dark piece that slope now there's a lot of folklore passed down in woodworking and it doesn't always serve to help the new woodworker sometimes it confuses so deciding what angle or what slope should those tails be remembering that the joint is put together so that it resists force in one direction primarily which is the drawer front trying to be pulled off from the drawer side we're going to go through talk about this explain how and why and hopefully by the time we're done you'll know what's best for your work so we'll start off by answering the question what is a dovetail ratio and typically we talk in ratios you hear one and eight one and seven one and six one and five maybe one and four typically we don't talk about degrees and how do we determine that ratio or how do we mark it well sometimes they would use what was called a sliding t bevel but you'd have to be able to find out well what angle do we actually want if we're talking one and six what we would do is on the edge of a board we would measure over one inch and then measure down six inches and that angle that is determined by those two dimensions would be rise over run or one and six and then you would take your sliding t bevel and you would lay it on there lock it in place and now you could go in and you could lay out the side of each tail and again what we're talking about is the markings that we're going to make in this play case on the piece of walnut now i use a dovetail marker which has a one and six and a one and seven ratio so a one and seven simply means instead of coming over one inch and going down six you're gonna come over one inch you're gonna go down seven and that angle would be a little bit less now if you actually were to translate those into into angles the 1 in 6 ratio is approximately 10 degrees and the 1 in 7 ratio is approximately eight degrees okay so why different why one and six one and five one and seven one and eight well on pine or other soft woods where the wood will more readily compress to compensate for that they would increase the splay or increase the angle and go one and six one and five now the danger is that this grain right in here is very short so the more you undercut it by coming along here the more fragile you can make these corners so you have to be aware that at some point you're going to risk having these break off when you assemble with hardwoods being a much more robust wood they could get away with a much less angle so they would work with a one and seven maybe even a one and eight and that further strengthens these corners without causing a weaker joint because again you got in this case you got maple and walnut both are hardwoods both aren't going to compress very readily makes for a strong joint my argument is this back then 100 plus years ago when the glues were not as good as they are today you had to rely on the mechanical strength of the joint to hold it together the glue was there but you really couldn't rely on that alone i think our our adhesives today are actually stronger than the wood itself so you can almost i wouldn't say eliminate but you can you can forget about a lot of the mechanical portion of the joint it's not nearly as important as it once was i then say okay well let's look at this as the at the aesthetics now as an example this i built this long time ago and i used to be fixed on one and seven this is a one in seven ratio so is this box this box goes back i think i built this in 1986 or 87. and those slopes are not very pronounced now this is hard to see because there's not much as much contrast to get a little more here what i noticed is you started to get five six seven ten feet away and you could barely notice the slope sometimes it started to look like a box joint on the other hand because of the extra slope you got with a one and six ratio you could really notice the slope as far as you as in fact as far as ways you can still see the joint you can still see and tell that it was a dovetail i started several years ago doing all of my dovetails in one and six for that reason i just think it looks better recognizable from a distance as a dovetail so in wrapping this up i want to show you a test that i think should put to rest any concerns you have about the strength of the dovetail joint as i mentioned glues today are superior to what they were a hundred years ago more worry more about what it looks like don't worry about whether or not it's going to be strong enough so here's a dovetail a through dovetail three tails cut in a piece of 5 8 inch northern white pine not the strongest wood in the world and i'm going to put it down there on the floor and that's a slippery floor and i'm going to stand on it and prove that that joint is stronger than you'll ever need it to be so don't worry about the angles in your dovetails go with what looks best and my money says the one and six if you like my work and enjoy my style of teaching click on any one of these videos and help take your woodworking to the next level i've always said better tools make the job so much easier if you click on the link below the chisel and plane icon it'll take you to our site and introduce you to all the tools that we actually manufacture right here in our shop it'll also give you information on our online and in-person workshops

Channel: RobCosman.com

Views: 19,957

Keywords: dovetail joint, cutting dovetails by hand, dovetail ratios, how to cut dovetails, how to cut dovetails by hand, sliding bevel, hand cutting dove tail joints, hand cut dovetails, cutting dovetails, dovetail angles, better dovetails, dovetail ratio, dovetails for beginners, making dovetails, through dovetail, rob cosman

Id: uNmmcuDnVgA

Length: 6min 31sec (391 seconds)

Published: Sat Aug 06 2022