FINALLY- A better way to cut dovetails by hand! (Cosman's Tips and Tricks)

hi I'm James Hamilton from stumpy nubs woodworking journal and today I'm going to show you how Rob Cosman has changed dovetailing forever I don't cut a lot of dovetails by hand and I used to struggle with getting consistently tight-fitting joints then I discovered Rob Cosman he's one of the few people on this earth that is a true dovetailing savant he is that good he's been teaching dovetailing since the 1980s which has afforded him the opportunity to observe thousands of woodworkers of all skill levels and in that time he noticed something many people are struggling with these same things specifically they have difficulty achieving the proper position and angle of each cut and that leads to poor fitting joints that just look terrible so Rob dedicated himself to developing specific tools and innovative techniques that addressed those specific problems and once he started implementing them into his classes he found that even new woodworkers could learn to cut beautiful dovetails very quickly and once they did it took their woodworking and the satisfaction it brought them to new levels we're not going to go through every step in the dovetailing process Rob's already made several videos that walk you through it in great detail I'll link to one in the notes below this video just click on show more if you're on YouTube I'm gonna focus on the parts that make this method unique including some of the techniques that you may never have even seen before and some modifications that Rob has made to traditional woodworking tools that help a great deal as well you may be able to modify some of the tools you already own or you may choose to buy some of those tools from Rob's website it's up to you I don't make a dime either way but don't be scared away just because you see me use a tool you don't have you can still apply many of these tips with the tools you already own now let's get to the dovetailing again I'm focusing on what makes Rob's methods different not necessarily every step in the dovetailing process so I've already laid out the tails half of the joint with a pencil and I've scribed the base lines across the face of each board with a marking gauge Rob recommends cutting a shallow rabbet on the inside face of your tails board this help you align your joint later if you have a rabbiting plane you can use that to keep with the whole hand tool vibe otherwise you can use a router table or a table saw the rabbits only a 30 seconds or so deep and it goes right up to your marking gauge along the designates the thickness of the mating tails board before we cut let's talk a minute about the saw you're using for a saw to cut precisely you have to be able to start it easily in the cut if it skips a little bit before the teeth establish a curve you can easily jump out of your line this saw which rob designed himself has very fine teeth for the first two inches with a negative rake angle so there are a lot less aggressive and will start the cut very easily while the coarser more aggressive teeth on the rest of the saw plate will finish the cut quickly once a cut is started a lot of people have a tendency to let the saw wander to the sides in the kerf this produces a crooked cut and gaps that just look terrible in the joint one of the key differences between a quality dovetail saw and one of the cheap multi-purpose saws you might buy to Home Center is that dovetail saws have almost no set in the teeth only a couple thousandths of an inch per side very little set means the kerf will be tighter against the sides of the soft plate so you can't tip it to the side once the cut is started it's almost like the saw is self guiding as long as you start at the correct angle you can be sure that the saw will maintain that angle to the bottom of the curve but how do you start at the correct angle traditional dovetailing methods require the saw to be held at six different angles when you cut the tails you have to hold the saw perpendicular to the face of the board tilt it to the right side for the one side of the tail and then to the left for the other side of your tail then when you cut the pins you have to match the two tail angles and you have to hold your saw plumb for each cut six saw positions and you're often worrying about two at once no wonder people are afraid of dovetailing according to Rob's method though you don't have to worry about most of those angles this is important because a lot of dovetailing is muscle memory over time you develop the ability to feel your angles and if you can reduce the number of angles you have to learn to feel your learning curve will be dramatically lowered so instead of training your arm to recognize and hold six different positions we're going to focus on just two and let the others take care of themselves on the girls have to join all I have to worry about is cutting straight across the endgrain holding my saw perpendicular to the face of the board if I can do that my tails will come out just fine sure I'm still gonna tilt my saw to the left and to the right but those angles don't matter I'm just concerned with one angle keeping the saw perpendicular to the face of the board and if I tilt a little too far to the side and I miss my pencil line so what that'll be corrected when I cut the second half of the joint traditionally once you cut the sides of each tail you would chisel out the waist in between and then use a pencil to trace it onto the pins board but here's where Rob's method really gets interesting we're gonna use the saw to transfer our lines before removing the waist this isn't an entirely new idea I've seen this in old woodworking books I have it's alright under he'll do it on a couple episodes of the wood right shop on PBS the result isn't that different from tracing with a pencil just instead of pencil lines you have little scratches on the end grain of your pins board and then with this method you would have to cut next to those scratches just as you would the pencil lines because if you cut directly on them your joint would be too loose but cutting next to a line or a scratch is what messes a lot of people up because it introduces room for all sorts of air Rob's method eliminates that problem by introducing offsets but simply if I offset my tails board to the right or to the left an equal amount to the thickness of my saws kerf I can then cut right on my line or better yet drop the saw right into the little scratch on the end grain this will eliminate the common error of cutting too close or too far from your line and it means I don't have to worry about holding my saw and precise angles as I cut my pins to match my tails the scratches line the saw up for me originally Rob used a metal shim that was exactly as thick as his saw plate to offset his workpiece but you probably don't have such a shim so Rob started using his marking gauge as a depth gauge this has a circular cutter on the end that shaped like a cup so the screw holding it on is set below the cutting surface I put the marking gauge on the side of my saws teeth let the cutter drop down so I hear a clink on the metal side of my hand plain before I lock it in place this gauge is now set to the thickness of my saws kerf including the set of the teeth I'm going to use it to offset my tails board to the left a distance equal to the thickness of the saws curve now I can transfer the shape of my tails onto the end of my pins board using my handsaw or better yet to make it easier Rob put a piece of his saw plate in a marking knife which I think is just a great idea you'll notice that I offset my board to the left then mark just the right side of each tail then I offset the board to the right and Mark the left sides and as I mark I'm careful to hold down my pins board firmly I don't want it to move at all that shallow rabbet I cut on the underside makes it a lot easier sort of locks over the end of the pins board so I only have to apply downward pressure to keep it still now remember when I said I didn't have to worry about the angle of the sides of my tails because I would cut the pins to match whatever angles I ended up with well now is that time but I still don't have to worry because those angles are already set for me by the scratches in the end grain I just drop my saw in each shallow kerf and cut downward it's all I have to worry about making plumb cuts that go straight down if I can do that the rest is gonna take care of itself one way to make sure you're getting plumb cuts is to mount your board straight up and down in your vise I use a hand plane to do this Rob also believes a heavier dovetail saw will help you feel plumb because gravity is working with you he designed his saw with an extra heavy spine and made the handle from a composite material that adds weight while maintaining balance this saw is about twice as heavy as any other dovetail saw I've used that way it also helps you begin your cut more accurately you may feel plumb you may even align the cut plumb with your eyes but if you have to apply much downward force to begin the cut you can easily tip the saw a little bit out of plumb this saw cuts quickly under its own weight and it's more likely to stay in the kerf instead of skipping to the side as you begin which eliminates yet another cause for air now I can cut away the waste between my pins and Tails which is a lot easier if I cut most of it away with a fretsaw this is another thing rob has experimented with he found that 12 and a half teeth per inch in a skip tooth configuration works best and the closer you get to your gauge line with the fretsaw the faster your chisel work would be Rob also recommends using a chisel to create a curve for your saw to run in when you trim the waste from the half pin area on the tails board this is important because if you cut past your line you'll have a gap that will be very visible in a finished joint the rest is done with a chisel and a mallet I have a lot of different chisels but this is a special one that Rob and I BC developed I have just a quarter inch and a half inch size that I use exclusively for dovetailing so they're always super sharp Rob made this mallet too and that is hockey tape on the handle that reduces the amount of strength it takes to grip it which makes it much more comfortable to use over long periods of time Rob's full of great little ideas like this that he's developed over decades in the craft here's another thing that trips up a lot of beginners they drop the edge of their chisel right in there marking gauge line and they top out a big hunk of waste then they wonder why their joints look terrible the problem is they're taking too big a bite at once if you have too much material on the bevel side of your chisel your tool will deflect backwards and across your line pair some of that waste away the stuff you have left behind when you fret sod most of it out so you leave only about a sixteenth of an inch or less to remove when you finally do drop your chisel into your marking gauge line and pair out the rest I also like to angle my chisel one or two degrees toward the end of the board I got half way through one side then half way through the other side and the result is a slight undercut or hollow area between the pins and the tails I like to make it Hollow there because I want to be sure there is no hump that would prevent the joint from fully closing under cutting like this doesn't affect the strength of the joint but it does save you a lot of time fine-tuning it later once the waste is gone Rob also suggests cutting chamfers on the inside edges of your tails not all the way to the corners of course that would show on the finished joint these chamfers will make it easier to assemble the joint and it'll give some relief for glue when that time comes I like rob husband's methods because it eliminates a lot of the most common errors people make when cutting dovetail joints I also like the modifications he's made to some traditional woodworking tools because they make the job a lot easier and more accurate I'll put a link in the notes below this video so you can check it out for yourself as well as a link to one of his more extensive dovetailing tutorials besides helping people cut flawless dovetails Rob is also passionate about what he calls his Purple Heart project which uses hand tool woodworking as therapy for people who suffer from traumatic physical and mental injuries of war if you're a veteran or you know someone who is send them over to rob Cosman calm Rob's very generous with his time and resources including giving out free lifetime memberships to his online workshops and every year he selects 24 wounded veterans for all expense paid trips to his hands-on workshops this is an expensive endeavor so if you aren't a wounded veteran but you'd like to support his effort you'll find more information about that on his website as well for more great tips tricks and tutorials designed to make you a better woodworker check out stumpy Nub's woodworking journal you can read and subscribe for free at stumpy nubs com

Channel: Stumpy Nubs

Views: 462,010

Rating: 4.8767123 out of 5

Keywords: woodworking, stumpy nubs, rob cosman, purple heart project, dovetails, hand tools, dovetial saw

Id: y-fLkdVRMwE

Length: 12min 49sec (769 seconds)

Published: Fri Jan 18 2019

Reddit Comments

[u/sexquipoop69]

I think this dude has a crush on Rob Cosman

[u/overlord2767]

"Honey, if you mention Rob one more time I'm taking the children and leaving you" - this guy's wife probably

[u/pepprish]

This guy reminds me of a young Rob cosman

[u/its_Gur]

Rob Cosman.

[u/PM_ME_UR_LIPZ]

Stupid sexy woodworking. Why must your fibrous carcasses be so unforgiving?

[u/fanzel71]

Excellent information. Thanks for posting this.

[u/[deleted]]

I am a cabinetmaker and this is waaaay too much thinking into a dovetail. Practice. Cut it off then practice more. Once you are over a hundred you will be fine and you will have plenty to fill your stove in your workshop.

[u/Pronage]

Why wouldnt you use the saw blade itself for the offset. hold it flat against the side of the tail board and push it till the tooth is flush against the side of the pin board. The side of the tail board will keep in perpendicular and you can use your finger to tell when its flush against the pin board. You can feel pretty precisely with your finger, to a couple thousandths of an inch so im sure it would be adiquite for this.

[u/swissarmy_fleshlight]

I have to stop using my swiss army knife for these jobs.