(stop) getting groovy with it

[estimated reading time 6 minutes]

you want to cut a groove. a stopped groove. awesome. it’s a fundamental skill but often becomes one you start getting into specialty tools and complex approaches to make happen. but none of those things is necessary or, in many cases, even wise. there have been so many discussions online and offline lately about plows, combinations, grooving and rabbet and shoulder planes and special chisels and kerfing tools and … wow. there are two simply ways to cut a stopped groove — one involving electricity and the other involving nothing more than a few basic sharp tools and your head. and a mallet, though you could use your head for that, too, i suppose. though i don’t recommend it. unless you think vaccines are a bad idea. then you should probably use your head to pound the chisel cause … it’ll make your local supermarket less potentially-infectious. politics aside, though (and i’m a hardcore communist if anyone’s asking), let’s take a walk down a stopped groove.

before we really get started, though, let’s get something clear. dado is an arcane term and there is no place in modern english for unnecessarily-technical language. call them grooves regardless of direction and we will move on from the shadows of judgment and tedious linguistic obsessions. if you want to insist on there being a fundamental difference between “groove” and “dado”, this is not the article for you. and i’m not the writer for you. yes, there is a historical argument for differentiating between withgrain and crossgrain cutting. but it’s a weak argument and, even in cases where this matters, calling them “withgrain grooves” and “crossgrain grooves” is far more sensible because it doesn’t require any new terminology — and i’m always in favor of eliminating any technical language we can (in classes, i don’t use the term “rabbet”, for example, except to explain that what i’m calling a “ledge” is often referred to by that more technical term — there’s no situation where students want to learn more words unless they’re necessary and linguistic gatekeeping is simply keeping young people from the craft).

that aside, shall we begin?

there are many reasons you might need to make a groove in a board but here are the two most common — drawer bottoms and grooves for shelves in case/bookshelf sides. in the case of drawer bottoms, you either want the groove to stop before it gets to the front of the drawer but escapes the back or stops before it hits either (i think stopping before it hits either looks cleaner and i use full-height drawer-backs even on dovetailed drawers but many people take the more-traditional approach of a floating bottom and a back that actually stops at the top of the bottom panel — if you can’t picture this, look at a traditional american piece from the eighteenth or nineteenth centuries with drawers and the back of the drawer will probably be above the drawer-bottom, allowing the bottom to slide in and out to be replaced, held in place with hails into the bottom of the back piece projecting from the bottom of the bottom. if that’s not a complex use of directional words, i don’t know what is. i should add a diagram but i think i’ll just say it’s a good excuse to go visit a furniture museum or antique store. for those of you in europe or australia, by the way, this technique was extremely common in both places, too, though not as comprehensive as in america. if you’re in asia, this was generally not done so you’ll need to experience your short-back antiques vicariously [with the help of google images and the metropolitan museum].

you have your reasons, though, whatever they are. you want to cut a stopped groove to house a piece. i’m going to imagine this is for a shelf but the procedure is exactly the same regardless of the target dimensions. we’re going to use some pretty common ones, though, for demonstration purposes. we have a shelf 25cm deep and 18mm thick that needs to sit 9mm into a groove. that’s a reasonable size for a shelf made of standard hardwood stick sitting in a similar-thickness side. it doesn’t matter how wide the shelf is for our example. what you need is a 9mm-deep groove that’s 18mm tall and 250mm wide (or the other way around, depending on which axis you’re referencing, though this difference in language doesn’t matter in the process).

there are lots of ways you can do this. you can chisel the ends and use a plane to remove the waste. you can set up stop blocks on a router table and do it the powered way. but those are cumbersome and require expensive tools. what we want is a way to do this with nothing more than what we already have on-hand but without sacrificing any accuracy. first, let’s look at the handtool-only way.

you’ll need four pieces of stock but their size doesn’t really matter as long as they’re flat on two perpendicular sides and longer than the groove (well, two of them need to be this long and they’ll probably have offcuts long enough to be the other two, which only need to be as wide as the groove). smooth your stock so it’s perfect on those two sides — in practice, just smooth it so it’s perfect on all four sides while you’re at it because it will make attachment and pressure easier and we’re not talking about large pieces here. now cut the pieces exactly the length of your groove. take two other pieces and cut them at least the width of the groove plus the thickness of both sides you just made. now here’s the trick. attach them to the board so they are forming the perimeter of the groove you want but doesn’t exist yet.

how you attach them is up to you. i use clamps or glue if absolutely necessary. ca (cyanoacrylate) is brittle and i’m going to sand the surface after. you can stick some tape to the board and glue to the tape. you can use double-stick tape if you have some that’s strong enough. if it’s a big enough groove and you have the clamps, you can clamp the blocks in place (i do this for larger ones whenever i can to save on glue and — well, ca glue makes my head spin and i chisel better when i’m not high). you can use hot-glue, too, if you prefer, on the outside edges of your perimeter — just make sure the inside edges don’t lift.

with them attached, though, you can start. take a chisel and start carving the edge with it flat against all the faces of your fence. you’ll never cut the groove too large because the fence is covering the rest of the board. this may feel a bit cumbersome at first but you get used to it and you’re only using the fence for a very short time. with the outline in, you can get to excavating the center section. your guide-fence is short enough and you can start chiseling from both ends. start from the center. dig in, create a v almost the width of the groove, widen the v. expand it to the whole length of your groove. when you have that done a few millimeters deep the whole size of the groove, take your chisel (perhaps a narrow one and a wide one if you want to be efficient) and pare all the sides.

here’s the other piece of the trick. you’ve now got the shoulders of the groove and the rest doesn’t matter. if it flares out from here, you’re good and it’s hidden within the groove. take off the fence. use the same method with the chisel to create another v to take it down another level and pare the sides. the shoulder you’ve made should be enough to reference your chisel in just like it’s a saw cut. slice the sides, slice the ends, dig from the middle, scoop it out and repeat until you’re deep enough. in most of these cases, you don’t need a flat bottom, just a minimum-depth the length and width of the groove to get the thing in — if your piece is 18mm thick and you need 9mm, some of it might be 11 or 12mm deep and that won’t really matter in most cases. perhaps in yours it does. you can check with the sliding part of your combination square or, if you have one, a depth-gauge to check your progress. the fence, which most people seem to think of as a tool at the end of the process, has created a guide from the actual workpiece so you will stay on track without the need for a speciality plane or adjustable fence.

in a matter of minutes, you have a groove that should fit your needs. now you can (and this is where the best part appears) use the same fence system for the rest of the grooves you need to cut the same way, even if they have different depths. if you’re making a bookshelf you might have a dozen or more of these to cut. if it’s a case piece with drawers, you could be looking at far more than that.

the powered route is similar. once you have your fence in place, just plunge your router in and let the bearing-guided bit register on the fence — no router-base attachments necessary. no, this isn’t as efficient as a router with an integrated fence but it’ll work and cost you nothing but a few scraps and a little tape or glue.

hope that helps at least a few. i use this on a fairly regular basis when i don’t want to use my plunge-router or when i want the zen of almost-silent shop time (in other words when it’s after 9 at night and my neighbors are likely to scream at me for using a router). thanks for reading!

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thank you for reading. your eyes have done me a great honor today.