How To Clean Up The Bottom Of A Mortise

Nosotros may receive a commission when you utilize our chapter links. Withal, this does not impact our recommendations.

The torn grain, gaps and general loose fit around these through-mortises are unacceptable to the modern
woodworker – though these defects were once common. This is an Arts & Crafts bookcase that once graced a church library in Lexington, Ky.

Woodworkers expect this joint to be tidy and tight, not ragged and gappy. We explore the best ways to brand this sometimes-vexing hole.

by Christopher Schwarz
from the Winter 2008 event of Woodworking Magazine

The history of the through-mortise begins with a joint that was necessary because of the tools and engineering science of the day, and it ends with a joint that flaunts the skills of the modern woodworker like a prize chicken at a county fair.

A through-mortise – which is where the joint passes entirely through a leg or stile – is rarely structurally necessary in modern furniture thank you to high-strength glues and auto-cut joinery surfaces that maximize the amount of wood-to-wood contact.

Merely they are sometimes necessary for other reasons: They are a hallmark of certain furniture styles, including some early American and European pieces, Arts & Crafts furniture and stick chairs, such equally Windsors and Welsh chairs.

This through-mortise on the lower leg of a Gustav Stickley rocker would non pass modern muster. The ends of the mortise were left circular and the tenon was foursquare. On other joints in this chair you can encounter violent left from the wearisome machine.

And in contemporary piece of work, through-mortises are often used as the calling card for a handmade slice of furniture. Few furniture factories go to the problem of making this joint, and then individual makers utilise it to differentiate their piece of work from the fiberboard garbage that clogs our stores, homes and landfills.

The reason the through-mortise is a affiche kid for handmade piece of furniture is that information technology is a claiming to make well – much similar the dovetail articulation. People's eyes are drawn to expressed joints like this, and small gaps make big impressions.

I've spent years investigating diverse techniques for making this joint tidy and evidence-worthy. The following story is the outcome of my trials and occasional revelations.

Real-world Through-mortises

This through-tenon on an arm of a Charles Stickley side chair shows what skilful work looks similar in a highly visible surface area. The joint isn't airtight, only it'south quite skillful considering the 100 years that take passed since its making.

Through-mortises appear in the earliest extant furniture. Egyptian beds and stools typically used the through-mortise to join their legs and rails. Exactly why this articulation was employed isn't known, but we can guess. With a lack of reliable glues, a through-mortise joint allows lots of woods-to-wood contact – friction if you will – that will keep the joint together. Sometimes these joints were even lashed together, and the tenon passing through the mortise allowed this.

As article of furniture evolved through the 18th and 19th centuries, it became much more the norm to obscure joinery rather than show it off. Piece of furniture craftsmen avoided the problem of unreliable glues by cutting a bullheaded mortise (which is open merely on one end) then driving a peg through the finished mortise and tenon to mechanically lock the pieces.

Even so, in the world of the workers who fitted out houses with doors and window sash, the through-mortise remained a staple of the trade. When joining the rails and stiles of windows and doors, through-mortises are typical fifty-fifty in houses built at the dawn of the 20th century.

The reason for that is two-fold. Doors and windows are made up of heavier pieces that need to take more abuse than a piece of fine article of furniture. Plus, a through-mortise has other advantages. It can exist cut using fewer jobsite tools (a chisel and a mallet is all that is needed) and you lot don't have to take the fourth dimension to clean the bottom of the mortise. Information technology can exist assembled and wedged with fewer clamps – you tin put i clamp on the joint, wedge it from the outside and immediately remove the clamp. And things can exist more than hands dismantled for repair – dig out the wedges and pull the joint apart.

On the show side of a mortise, the edges must be crisp and not rounded over by the tool. Make lots of light cuts, and so sweep the first bits of waste away using your chisel'due south edge flat on your work.

And because the result was usually hidden by paint or by its location on the edges of doors or in a window casing, the articulation didn't accept to look perfect. It simply had to hold things together.
That'south how things stood until the furniture factories came along. Some of the earliest factory machinery was designed to cut mortises and tenons. But in an endeavor to brand less-expensive piece of furniture for the masses, factories began using less-reliable joints – such every bit dowels – that could exist made quickly and cheaply with precision machinery.

From the outside of the furniture, the results looked the aforementioned. A blind tenon and a doweled joint are indistinguishable from the outside of a piece. And I've even seen doweled pieces that have a fake exterior peg, which implies in that location is a tenon in there instead of two skimpy bits of dowel.

Some piece of furniture consumers were unhappy with this mass-produced flimsy furniture coming out of the factories. And from this discontent rose the Arts & Crafts movement. At its all-time, the Arts & Crafts motion celebrated stout joinery. High-quality pieces used through-mortises as a way to show the consumer how the joint was made. (Let's ignore, for a moment, the Arts & Crafts shysters that would nail on a fake through-tenon to fool the customer.)

In router-cut mortises similar this, the corners are tough to square up without botching them. Y'all can score your layout lines with deep pocketknife cuts, which helps. Ultimately, if y'all take this path you are going to take to get good with a chisel.

These visible joints were put in visible places – on the tops of chair artillery, on the fronts and ends of casework pieces, on legs. Still, making these visible joints must have proved to be a challenge. They appear on merely the best pieces. And they don't ever look tidy (especially the ones that are shut to the floor).

So the through-mortise began to disappear once again from article of furniture as the popular styles began to change to favor surface ornament to structural honesty.

Today the through-mortise articulation is used when you are reproducing certain piece of furniture styles or are attempting to display your craftsmanship. No matter why you lot make this joint, the standards for what is acceptable have changed. Gaps betwixt a through-mortise and its tenon aren't acceptable in proficient work.

Ii Kinds of Through-mortises

Press and hold a ruler to a flat face of your hollow chisel. Compare the ruler to your layout lines to see if the chisel is twisted. This fob is remarkably authentic.

So the imperative is to brand this joint look perfect, and the tolerances are tough to hit. Where do y'all begin? First, it's helpful to know there are ii kinds of through-mortises, each of which requires a different strategy.

The beginning kind of through-mortise has an opening that is skinny and long – for case, 1⁄4″ broad x iii″ long. This is the kind of through-mortise you would run across when you bring together a side rails on a Morris chair with the chair'south front leg. It besides is mutual to see this mortise where a shelf intersects the side of the carcase.

The other kind of through-mortise is simply larger – information technology can be either rectangular or square. This is the kind of through-mortise you would see when you join a chair leg to an arm.
Let's walk through some of the techniques for cut each of these.

Skinny and Long: Employ Square Tooling

I'one thousand in the addiction of using the spring-frog method of mortising. Skip a space with every hole, then clean up betwixt the holes. Other craftsmen I respect say the holes should overlap slightly to meliorate chisel cut. Effort both and decide.

For any through-mortise, you can use a mortise chisel and a mallet. And if I have 4 or fewer to exercise, that is typically how I'll go along. You lay out the mortise opening on both sides of the joint then brainstorm the banging. When I make my layout marks, I score them as securely equally possible on the face of the joint that will be visible. Deep score lines help you remove waste cleanly.

This is particularly of import if the long axis of the mortise runs across the grain (like it does in the bookshelf in this issue). When y'all chisel out a mortise beyond the grain, it has a tendency to tear out around the joint, peculiarly in forest such as oak and ash.

Begin chopping out the side that will be obscured. Working from this side first allows you lot to get your chisel skills warmed upwardly. If the chisel is cutting true, I'll bulldoze downward across the halfway signal. Though removing waste matter is more than difficult in deep cavities, information technology's more important to get the two ends of the mortise to come across. Then don't stop if things are going well.

Then flip the work and make a low-cal cut on the face up that will be visible. Some people will chop upwards the surface of the mortise with tight cuts then sweep the waste off the height of the mortise using the shaft of the chisel.

Here you can run across the result of accurate auto setup and careful layout. The mortise goes articulate through, and the rim of the mortise is crisp plenty for close inspection.

In one case the initial opening is cut, you can bulldoze more securely. Just be sure not to lever the chisel against the ends of the mortise when prying out the waste matter. This pry-bar action rounds over the rim of the go out wound.

If you are not going to cut the through-mortise by hand, two other common options are to employ a hollow-chisel mortiser or a plunge router with a straight bit and an edge guide.

I almost always choose the hollow-chisel mortiser. Hither's why: The router method is tiresome. Through-mortises that are shaped this way (long and skinny) are typically in thick textile – three″ thick is non uncommon. That can be a lot to enquire of a 1⁄4″-diameter router scrap. In fact, I've snapped off quite a few in deep cuts. If y'all go the router route, accept lilliputian bites. Information technology slows yous downwards, but information technology'south easier on the tooling.

Y'all too have to square up the ends of these router cuts (unless you want to make an authentic  and gappy Gustav Stickley-style joint). This is a lot to ask of a hand-held chisel in thick cloth. Yous take to accept care and take smaller bites so your tool doesn't go astray.

The hollow-chisel mortiser is fast and tin can make a clean cut if you gear up upwardly the machine with care. Let'southward brainstorm in that location. Y'all need sharp tooling. File the cutter of the auger-bit office of the tooling and rock the within and outside of the hollow chisel. For complete details on choosing the right bit and sharpening it, read our story on hollow-chisel tooling in the Spring 2007 issue.

The pattern-cutting bit (left) seems simpler (just make a pattern that is the right size), but y'all accept to gear up things so the bearing rides the pattern and there is plenty cutter showing to do the job. Bushing-guided patterns simply require a slightly oversized pattern.

You need to accept your hollow chisel set dead parallel to the machine'southward fence. Yous tin get there past trial-and-mistake. Only here'due south how to make it there with less error. Lay out a sample mortise on some exam scrap. Bring the hollow chisel close to your layout lines. At present press a 6″-long ruler against the hollow chisel and compare it to your layout line. The ruler will exaggerate any twist in the chisel and allow you to fine-melody it in the bushing of your hollow-chisel mortiser.

Now brand a sample mortise to confirm that you are cutting where you desire to cutting and that the chisel is parallel to the fence. Now get prepare to prepare your live stock. Normally, most instructions presume that your project parts are square. When making through-mortises, your parts have to exist as square equally possible. Double-check each part afterwards you lot square it up and before yous make your mortises. Small errors brand joints that won't go together. I've found that it pays to have the part'southward jointed confront confronting the mortiser's fence.

To bore the mortise, first work halfway through on one side. And so flip the work over and do the aforementioned thing on the other. If the machine is set up well, this work is extremely fast and clean.

Bigger Joints Require Unlike Tools
The rules change when the through-mortises go bigger. In one case your joints are wider than one⁄two″, and then hollow-chisel mortisers become hard to use. When your mortises are wider than i⁄two″, you take to shift your work both left-to-right and back-to-front end to clean out the mortise. That'south non always a simple thing to do with accuracy. And you actually need an X-and-Y sliding table. (Side note: I'grand aware there are bigger bits available for hollow-chisel mortisers, but they don't piece of work on the common benchtop machines.)

Hither you can come across how a design was assembled for a through-mortise. I utilize merely glue on the edges to bring together the parts – no biscuits or dowels. With plywood, there'south always enough long grain at the edges to brand this panel plenty strong.

Hither's the other thing that changes: Usually with larger through-mortises, you are  working on thinner stock, typically 3⁄four″- to 7⁄8″-thick stuff.

Then a new strategy is in order: router templates. Considering your stock is thinner, the one″-long straight bits take no problem cutting these joints with ease. Plus, as you'll shortly see, the routing template tin likewise exist a chiseling template for squaring upwardly the corners.

You lot can brand these router templates to use either a pattern-guided straight chip or a bushing installed in your router's baseplate. The templates for pattern-guided bits are simpler to make (no math), but it'southward catchy to become your bit's bearing and the thickness of your pattern all playing nice together.

On the other hand, the templates for bushing-guided bits require a little math (addition – plus its tricky friend, subtraction). But y'all're fooling around a lot less trying to match your bit and the thickness of the material out of which you are making your design. So really it's a wash as to which method is faster.

No affair which path you lot choose, you lot demand to make a design out of plywood (or solid wood) that has an opening with perfectly precipitous corners. Making that design is fairly elementary: I saw upward bits of plywood (typically one⁄2″ in thickness) and reassemble them as a panel that has the right-sized hole for my routing pattern.

Take niggling bites with the chisel. If you attempt to remove the unabridged corner in one whack, bad things tin happen. The template can shift. Or the chisel will steer itself outside the template – simply below the surface of your work.

Remove every bit much of the waste as you can with a Forstner bit, then clamp the router template in place. Be certain to secure the template to the outside face of your work. Rout out the remainder of the waste material but don't remove the template because its job isn't over. You tin can utilise its sharp corners to guide your chisel to square upwards the rounded corners.

This technique yields overnice well-baked corners on the outside of your work and ragged, torn-out corners on the inside surface (because there was no template to guide your chisel). This isn't a problem every bit long as the tearing isn't too severe.

Once you get the mortise cut, the tenons are easy. I cutting them close on my power equipment, then trim them to a snug fit with a shoulder plane, which also removes the marks left by the power tooling.

Become all xvi outcome of Woodworking Mag on CD or as a download.
For in-depth joinery instruction, download the "Joinery Master Class" video by Frank Klausz (7+ hours of instruction!)

---

Product Recommendations

Here are some supplies and tools we find essential in our everyday work around the shop. We may receive a committee from sales referred by our links; however, we accept carefully selected these products for their usefulness and quality.

• 

  Titebond Hide Mucilage

  

• 

  PSA Sandpaper Roll

  

• 

  Jig & Fixture Bar

  

How To Clean Up The Bottom Of A Mortise,

Source: https://www.popularwoodworking.com/techniques/make-clean-through-mortises/

Posted by: nicholsonmusere.blogspot.com

Share this post